aboutsummaryrefslogtreecommitdiff
path: root/src/rpc/layout
diff options
context:
space:
mode:
authorAlex <alex@adnab.me>2024-01-11 10:58:08 +0000
committerAlex <alex@adnab.me>2024-01-11 10:58:08 +0000
commit8a6ec1d6111a60e602c90ade2200b2dab5733fe3 (patch)
treeb8daac4f41050339c87106d72ce7224f7eef38aa /src/rpc/layout
parent723e56b37f13f078a15e067343191fb1bf96e8b2 (diff)
parent0041b013a473e3ae72f50209d8f79db75a72848b (diff)
downloadgarage-8a6ec1d6111a60e602c90ade2200b2dab5733fe3.tar.gz
garage-8a6ec1d6111a60e602c90ade2200b2dab5733fe3.zip
Merge pull request 'NLnet task 3' (#667) from nlnet-task3 into next-0.10
Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/667
Diffstat (limited to 'src/rpc/layout')
-rw-r--r--src/rpc/layout/graph_algo.rs405
-rw-r--r--src/rpc/layout/helper.rs294
-rw-r--r--src/rpc/layout/history.rs306
-rw-r--r--src/rpc/layout/manager.rs378
-rw-r--r--src/rpc/layout/mod.rs478
-rw-r--r--src/rpc/layout/test.rs157
-rw-r--r--src/rpc/layout/version.rs846
7 files changed, 2864 insertions, 0 deletions
diff --git a/src/rpc/layout/graph_algo.rs b/src/rpc/layout/graph_algo.rs
new file mode 100644
index 00000000..bd33e97f
--- /dev/null
+++ b/src/rpc/layout/graph_algo.rs
@@ -0,0 +1,405 @@
+//! This module deals with graph algorithms.
+//! It is used in layout.rs to build the partition to node assignment.
+
+use rand::prelude::{SeedableRng, SliceRandom};
+use std::cmp::{max, min};
+use std::collections::HashMap;
+use std::collections::VecDeque;
+
+/// Vertex data structures used in all the graphs used in layout.rs.
+/// usize parameters correspond to node/zone/partitions ids.
+/// To understand the vertex roles below, please refer to the formal description
+/// of the layout computation algorithm.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum Vertex {
+ Source,
+ Pup(usize), // The vertex p+ of partition p
+ Pdown(usize), // The vertex p- of partition p
+ PZ(usize, usize), // The vertex corresponding to x_(partition p, zone z)
+ N(usize), // The vertex corresponding to node n
+ Sink,
+}
+
+/// Edge data structure for the flow algorithm.
+#[derive(Clone, Copy, Debug)]
+pub struct FlowEdge {
+ cap: u64, // flow maximal capacity of the edge
+ flow: i64, // flow value on the edge
+ dest: usize, // destination vertex id
+ rev: usize, // index of the reversed edge (v, self) in the edge list of vertex v
+}
+
+/// Edge data structure for the detection of negative cycles.
+#[derive(Clone, Copy, Debug)]
+pub struct WeightedEdge {
+ w: i64, // weight of the edge
+ dest: usize,
+}
+
+pub trait Edge: Clone + Copy {}
+impl Edge for FlowEdge {}
+impl Edge for WeightedEdge {}
+
+/// Struct for the graph structure. We do encapsulation here to be able to both
+/// provide user friendly Vertex enum to address vertices, and to use internally usize
+/// indices and Vec instead of HashMap in the graph algorithm to optimize execution speed.
+pub struct Graph<E: Edge> {
+ vertex_to_id: HashMap<Vertex, usize>,
+ id_to_vertex: Vec<Vertex>,
+
+ // The graph is stored as an adjacency list
+ graph: Vec<Vec<E>>,
+}
+
+pub type CostFunction = HashMap<(Vertex, Vertex), i64>;
+
+impl<E: Edge> Graph<E> {
+ pub fn new(vertices: &[Vertex]) -> Self {
+ let mut map = HashMap::<Vertex, usize>::new();
+ for (i, vert) in vertices.iter().enumerate() {
+ map.insert(*vert, i);
+ }
+ Graph::<E> {
+ vertex_to_id: map,
+ id_to_vertex: vertices.to_vec(),
+ graph: vec![Vec::<E>::new(); vertices.len()],
+ }
+ }
+
+ fn get_vertex_id(&self, v: &Vertex) -> Result<usize, String> {
+ self.vertex_to_id
+ .get(v)
+ .cloned()
+ .ok_or_else(|| format!("The graph does not contain vertex {:?}", v))
+ }
+}
+
+impl Graph<FlowEdge> {
+ /// This function adds a directed edge to the graph with capacity c, and the
+ /// corresponding reversed edge with capacity 0.
+ pub fn add_edge(&mut self, u: Vertex, v: Vertex, c: u64) -> Result<(), String> {
+ let idu = self.get_vertex_id(&u)?;
+ let idv = self.get_vertex_id(&v)?;
+ if idu == idv {
+ return Err("Cannot add edge from vertex to itself in flow graph".into());
+ }
+
+ let rev_u = self.graph[idu].len();
+ let rev_v = self.graph[idv].len();
+ self.graph[idu].push(FlowEdge {
+ cap: c,
+ dest: idv,
+ flow: 0,
+ rev: rev_v,
+ });
+ self.graph[idv].push(FlowEdge {
+ cap: 0,
+ dest: idu,
+ flow: 0,
+ rev: rev_u,
+ });
+ Ok(())
+ }
+
+ /// This function returns the list of vertices that receive a positive flow from
+ /// vertex v.
+ pub fn get_positive_flow_from(&self, v: Vertex) -> Result<Vec<Vertex>, String> {
+ let idv = self.get_vertex_id(&v)?;
+ let mut result = Vec::<Vertex>::new();
+ for edge in self.graph[idv].iter() {
+ if edge.flow > 0 {
+ result.push(self.id_to_vertex[edge.dest]);
+ }
+ }
+ Ok(result)
+ }
+
+ /// This function returns the value of the flow outgoing from v.
+ pub fn get_outflow(&self, v: Vertex) -> Result<i64, String> {
+ let idv = self.get_vertex_id(&v)?;
+ let mut result = 0;
+ for edge in self.graph[idv].iter() {
+ result += max(0, edge.flow);
+ }
+ Ok(result)
+ }
+
+ /// This function computes the flow total value by computing the outgoing flow
+ /// from the source.
+ pub fn get_flow_value(&mut self) -> Result<i64, String> {
+ self.get_outflow(Vertex::Source)
+ }
+
+ /// This function shuffles the order of the edge lists. It keeps the ids of the
+ /// reversed edges consistent.
+ fn shuffle_edges(&mut self) {
+ // We use deterministic randomness so that the layout calculation algorihtm
+ // will output the same thing every time it is run. This way, the results
+ // pre-calculated in `garage layout show` will match exactly those used
+ // in practice with `garage layout apply`
+ let mut rng = rand::rngs::StdRng::from_seed([0x12u8; 32]);
+ for i in 0..self.graph.len() {
+ self.graph[i].shuffle(&mut rng);
+ // We need to update the ids of the reverse edges.
+ for j in 0..self.graph[i].len() {
+ let target_v = self.graph[i][j].dest;
+ let target_rev = self.graph[i][j].rev;
+ self.graph[target_v][target_rev].rev = j;
+ }
+ }
+ }
+
+ /// Computes an upper bound of the flow on the graph
+ pub fn flow_upper_bound(&self) -> Result<u64, String> {
+ let idsource = self.get_vertex_id(&Vertex::Source)?;
+ let mut flow_upper_bound = 0;
+ for edge in self.graph[idsource].iter() {
+ flow_upper_bound += edge.cap;
+ }
+ Ok(flow_upper_bound)
+ }
+
+ /// This function computes the maximal flow using Dinic's algorithm. It starts with
+ /// the flow values already present in the graph. So it is possible to add some edge to
+ /// the graph, compute a flow, add other edges, update the flow.
+ pub fn compute_maximal_flow(&mut self) -> Result<(), String> {
+ let idsource = self.get_vertex_id(&Vertex::Source)?;
+ let idsink = self.get_vertex_id(&Vertex::Sink)?;
+
+ let nb_vertices = self.graph.len();
+
+ let flow_upper_bound = self.flow_upper_bound()?;
+
+ // To ensure the dispersion of the associations generated by the
+ // assignment, we shuffle the neighbours of the nodes. Hence,
+ // the vertices do not consider their neighbours in the same order.
+ self.shuffle_edges();
+
+ // We run Dinic's max flow algorithm
+ loop {
+ // We build the level array from Dinic's algorithm.
+ let mut level = vec![None; nb_vertices];
+
+ let mut fifo = VecDeque::new();
+ fifo.push_back((idsource, 0));
+ while let Some((id, lvl)) = fifo.pop_front() {
+ if level[id].is_none() {
+ // it means id has not yet been reached
+ level[id] = Some(lvl);
+ for edge in self.graph[id].iter() {
+ if edge.cap as i64 - edge.flow > 0 {
+ fifo.push_back((edge.dest, lvl + 1));
+ }
+ }
+ }
+ }
+ if level[idsink].is_none() {
+ // There is no residual flow
+ break;
+ }
+ // Now we run DFS respecting the level array
+ let mut next_nbd = vec![0; nb_vertices];
+ let mut lifo = Vec::new();
+
+ lifo.push((idsource, flow_upper_bound));
+
+ while let Some((id, f)) = lifo.last().cloned() {
+ if id == idsink {
+ // The DFS reached the sink, we can add a
+ // residual flow.
+ lifo.pop();
+ while let Some((id, _)) = lifo.pop() {
+ let nbd = next_nbd[id];
+ self.graph[id][nbd].flow += f as i64;
+ let id_rev = self.graph[id][nbd].dest;
+ let nbd_rev = self.graph[id][nbd].rev;
+ self.graph[id_rev][nbd_rev].flow -= f as i64;
+ }
+ lifo.push((idsource, flow_upper_bound));
+ continue;
+ }
+ // else we did not reach the sink
+ let nbd = next_nbd[id];
+ if nbd >= self.graph[id].len() {
+ // There is nothing to explore from id anymore
+ lifo.pop();
+ if let Some((parent, _)) = lifo.last() {
+ next_nbd[*parent] += 1;
+ }
+ continue;
+ }
+ // else we can try to send flow from id to its nbd
+ let new_flow = min(
+ f as i64,
+ self.graph[id][nbd].cap as i64 - self.graph[id][nbd].flow,
+ ) as u64;
+ if new_flow == 0 {
+ next_nbd[id] += 1;
+ continue;
+ }
+ if let (Some(lvldest), Some(lvlid)) = (level[self.graph[id][nbd].dest], level[id]) {
+ if lvldest <= lvlid {
+ // We cannot send flow to nbd.
+ next_nbd[id] += 1;
+ continue;
+ }
+ }
+ // otherwise, we send flow to nbd.
+ lifo.push((self.graph[id][nbd].dest, new_flow));
+ }
+ }
+ Ok(())
+ }
+
+ /// This function takes a flow, and a cost function on the edges, and tries to find an
+ /// equivalent flow with a better cost, by finding improving overflow cycles. It uses
+ /// as subroutine the Bellman Ford algorithm run up to path_length.
+ /// We assume that the cost of edge (u,v) is the opposite of the cost of (v,u), and
+ /// only one needs to be present in the cost function.
+ pub fn optimize_flow_with_cost(
+ &mut self,
+ cost: &CostFunction,
+ path_length: usize,
+ ) -> Result<(), String> {
+ // We build the weighted graph g where we will look for negative cycle
+ let mut gf = self.build_cost_graph(cost)?;
+ let mut cycles = gf.list_negative_cycles(path_length);
+ while !cycles.is_empty() {
+ // we enumerate negative cycles
+ for c in cycles.iter() {
+ for i in 0..c.len() {
+ // We add one flow unit to the edge (u,v) of cycle c
+ let idu = self.vertex_to_id[&c[i]];
+ let idv = self.vertex_to_id[&c[(i + 1) % c.len()]];
+ for j in 0..self.graph[idu].len() {
+ // since idu appears at most once in the cycles, we enumerate every
+ // edge at most once.
+ let edge = self.graph[idu][j];
+ if edge.dest == idv {
+ self.graph[idu][j].flow += 1;
+ self.graph[idv][edge.rev].flow -= 1;
+ break;
+ }
+ }
+ }
+ }
+
+ gf = self.build_cost_graph(cost)?;
+ cycles = gf.list_negative_cycles(path_length);
+ }
+ Ok(())
+ }
+
+ /// Construct the weighted graph G_f from the flow and the cost function
+ fn build_cost_graph(&self, cost: &CostFunction) -> Result<Graph<WeightedEdge>, String> {
+ let mut g = Graph::<WeightedEdge>::new(&self.id_to_vertex);
+ let nb_vertices = self.id_to_vertex.len();
+ for i in 0..nb_vertices {
+ for edge in self.graph[i].iter() {
+ if edge.cap as i64 - edge.flow > 0 {
+ // It is possible to send overflow through this edge
+ let u = self.id_to_vertex[i];
+ let v = self.id_to_vertex[edge.dest];
+ if cost.contains_key(&(u, v)) {
+ g.add_edge(u, v, cost[&(u, v)])?;
+ } else if cost.contains_key(&(v, u)) {
+ g.add_edge(u, v, -cost[&(v, u)])?;
+ } else {
+ g.add_edge(u, v, 0)?;
+ }
+ }
+ }
+ }
+ Ok(g)
+ }
+}
+
+impl Graph<WeightedEdge> {
+ /// This function adds a single directed weighted edge to the graph.
+ pub fn add_edge(&mut self, u: Vertex, v: Vertex, w: i64) -> Result<(), String> {
+ let idu = self.get_vertex_id(&u)?;
+ let idv = self.get_vertex_id(&v)?;
+ self.graph[idu].push(WeightedEdge { w, dest: idv });
+ Ok(())
+ }
+
+ /// This function lists the negative cycles it manages to find after path_length
+ /// iterations of the main loop of the Bellman-Ford algorithm. For the classical
+ /// algorithm, path_length needs to be equal to the number of vertices. However,
+ /// for particular graph structures like in our case, the algorithm is still correct
+ /// when path_length is the length of the longest possible simple path.
+ /// See the formal description of the algorithm for more details.
+ fn list_negative_cycles(&self, path_length: usize) -> Vec<Vec<Vertex>> {
+ let nb_vertices = self.graph.len();
+
+ // We start with every vertex at distance 0 of some imaginary extra -1 vertex.
+ let mut distance = vec![0; nb_vertices];
+ // The prev vector collects for every vertex from where does the shortest path come
+ let mut prev = vec![None; nb_vertices];
+
+ for _ in 0..path_length + 1 {
+ for id in 0..nb_vertices {
+ for e in self.graph[id].iter() {
+ if distance[id] + e.w < distance[e.dest] {
+ distance[e.dest] = distance[id] + e.w;
+ prev[e.dest] = Some(id);
+ }
+ }
+ }
+ }
+
+ // If self.graph contains a negative cycle, then at this point the graph described
+ // by prev (which is a directed 1-forest/functional graph)
+ // must contain a cycle. We list the cycles of prev.
+ let cycles_prev = cycles_of_1_forest(&prev);
+
+ // Remark that the cycle in prev is in the reverse order compared to the cycle
+ // in the graph. Thus the .rev().
+ return cycles_prev
+ .iter()
+ .map(|cycle| {
+ cycle
+ .iter()
+ .rev()
+ .map(|id| self.id_to_vertex[*id])
+ .collect()
+ })
+ .collect();
+ }
+}
+
+/// This function returns the list of cycles of a directed 1 forest. It does not
+/// check for the consistency of the input.
+fn cycles_of_1_forest(forest: &[Option<usize>]) -> Vec<Vec<usize>> {
+ let mut cycles = Vec::<Vec<usize>>::new();
+ let mut time_of_discovery = vec![None; forest.len()];
+
+ for t in 0..forest.len() {
+ let mut id = t;
+ // while we are on a valid undiscovered node
+ while time_of_discovery[id].is_none() {
+ time_of_discovery[id] = Some(t);
+ if let Some(i) = forest[id] {
+ id = i;
+ } else {
+ break;
+ }
+ }
+ if forest[id].is_some() && time_of_discovery[id] == Some(t) {
+ // We discovered an id that we explored at this iteration t.
+ // It means we are on a cycle
+ let mut cy = vec![id; 1];
+ let mut id2 = id;
+ while let Some(id_next) = forest[id2] {
+ id2 = id_next;
+ if id2 != id {
+ cy.push(id2);
+ } else {
+ break;
+ }
+ }
+ cycles.push(cy);
+ }
+ }
+ cycles
+}
diff --git a/src/rpc/layout/helper.rs b/src/rpc/layout/helper.rs
new file mode 100644
index 00000000..9fb738ea
--- /dev/null
+++ b/src/rpc/layout/helper.rs
@@ -0,0 +1,294 @@
+use std::collections::HashMap;
+use std::ops::Deref;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use serde::{Deserialize, Serialize};
+
+use garage_util::data::*;
+
+use super::*;
+use crate::replication_mode::ReplicationMode;
+
+#[derive(Debug, Clone, Serialize, Deserialize, Default, PartialEq, Eq)]
+pub struct RpcLayoutDigest {
+ /// Cluster layout version
+ pub current_version: u64,
+ /// Number of active layout versions
+ pub active_versions: usize,
+ /// Hash of cluster layout update trackers
+ pub trackers_hash: Hash,
+ /// Hash of cluster layout staging data
+ pub staging_hash: Hash,
+}
+
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub struct SyncLayoutDigest {
+ current: u64,
+ ack_map_min: u64,
+ min_stored: u64,
+}
+
+pub struct LayoutHelper {
+ replication_mode: ReplicationMode,
+ layout: Option<LayoutHistory>,
+
+ // cached values
+ ack_map_min: u64,
+ sync_map_min: u64,
+
+ all_nodes: Vec<Uuid>,
+ all_nongateway_nodes: Vec<Uuid>,
+
+ trackers_hash: Hash,
+ staging_hash: Hash,
+
+ // ack lock: counts in-progress write operations for each
+ // layout version ; we don't increase the ack update tracker
+ // while this lock is nonzero
+ pub(crate) ack_lock: HashMap<u64, AtomicUsize>,
+}
+
+impl Deref for LayoutHelper {
+ type Target = LayoutHistory;
+ fn deref(&self) -> &LayoutHistory {
+ self.layout()
+ }
+}
+
+impl LayoutHelper {
+ pub fn new(
+ replication_mode: ReplicationMode,
+ mut layout: LayoutHistory,
+ mut ack_lock: HashMap<u64, AtomicUsize>,
+ ) -> Self {
+ // In the new() function of the helper, we do a bunch of cleanup
+ // and calculations on the layout history to make sure things are
+ // correct and we have rapid access to important values such as
+ // the layout versions to use when reading to ensure consistency.
+
+ if !replication_mode.is_read_after_write_consistent() {
+ // Fast path for when no consistency is required.
+ // In this case we only need to keep the last version of the layout,
+ // we don't care about coordinating stuff in the cluster.
+ layout.keep_current_version_only();
+ }
+
+ layout.cleanup_old_versions();
+
+ let all_nodes = layout.get_all_nodes();
+ let all_nongateway_nodes = layout.get_all_nongateway_nodes();
+
+ layout.clamp_update_trackers(&all_nodes);
+
+ let min_version = layout.min_stored();
+
+ // ack_map_min is the minimum value of ack_map among all nodes
+ // in the cluster (gateway, non-gateway, current and previous layouts).
+ // It is the highest layout version which all of these nodes have
+ // acknowledged, indicating that they are aware of it and are no
+ // longer processing write operations that did not take it into account.
+ let ack_map_min = layout
+ .update_trackers
+ .ack_map
+ .min_among(&all_nodes, min_version);
+
+ // sync_map_min is the minimum value of sync_map among storage nodes
+ // in the cluster (non-gateway nodes only, current and previous layouts).
+ // It is the highest layout version for which we know that all relevant
+ // storage nodes have fullfilled a sync, and therefore it is safe to
+ // use a read quorum within that layout to ensure consistency.
+ // Gateway nodes are excluded here because they hold no relevant data
+ // (they store the bucket and access key tables, but we don't have
+ // consistency on those).
+ // This value is calculated using quorums to allow progress even
+ // if not all nodes have successfully completed a sync.
+ let sync_map_min =
+ layout.calculate_sync_map_min_with_quorum(replication_mode, &all_nongateway_nodes);
+
+ let trackers_hash = layout.calculate_trackers_hash();
+ let staging_hash = layout.calculate_staging_hash();
+
+ ack_lock.retain(|_, cnt| *cnt.get_mut() > 0);
+ ack_lock
+ .entry(layout.current().version)
+ .or_insert(AtomicUsize::new(0));
+
+ LayoutHelper {
+ replication_mode,
+ layout: Some(layout),
+ ack_map_min,
+ sync_map_min,
+ all_nodes,
+ all_nongateway_nodes,
+ trackers_hash,
+ staging_hash,
+ ack_lock,
+ }
+ }
+
+ // ------------------ single updating function --------------
+
+ fn layout(&self) -> &LayoutHistory {
+ self.layout.as_ref().unwrap()
+ }
+
+ pub(crate) fn update<F>(&mut self, f: F) -> bool
+ where
+ F: FnOnce(&mut LayoutHistory) -> bool,
+ {
+ let changed = f(self.layout.as_mut().unwrap());
+ if changed {
+ *self = Self::new(
+ self.replication_mode,
+ self.layout.take().unwrap(),
+ std::mem::take(&mut self.ack_lock),
+ );
+ }
+ changed
+ }
+
+ // ------------------ read helpers ---------------
+
+ pub fn all_nodes(&self) -> &[Uuid] {
+ &self.all_nodes
+ }
+
+ pub fn all_nongateway_nodes(&self) -> &[Uuid] {
+ &self.all_nongateway_nodes
+ }
+
+ pub fn ack_map_min(&self) -> u64 {
+ self.ack_map_min
+ }
+
+ pub fn sync_map_min(&self) -> u64 {
+ self.sync_map_min
+ }
+
+ pub fn sync_digest(&self) -> SyncLayoutDigest {
+ SyncLayoutDigest {
+ current: self.layout().current().version,
+ ack_map_min: self.ack_map_min(),
+ min_stored: self.layout().min_stored(),
+ }
+ }
+
+ pub fn read_nodes_of(&self, position: &Hash) -> Vec<Uuid> {
+ let sync_min = self.sync_map_min;
+ let version = self
+ .layout()
+ .versions
+ .iter()
+ .find(|x| x.version == sync_min)
+ .or(self.layout().versions.last())
+ .unwrap();
+ version
+ .nodes_of(position, version.replication_factor)
+ .collect()
+ }
+
+ pub fn storage_sets_of(&self, position: &Hash) -> Vec<Vec<Uuid>> {
+ self.layout()
+ .versions
+ .iter()
+ .map(|x| x.nodes_of(position, x.replication_factor).collect())
+ .collect()
+ }
+
+ pub fn storage_nodes_of(&self, position: &Hash) -> Vec<Uuid> {
+ let mut ret = vec![];
+ for version in self.layout().versions.iter() {
+ ret.extend(version.nodes_of(position, version.replication_factor));
+ }
+ ret.sort();
+ ret.dedup();
+ ret
+ }
+
+ pub fn trackers_hash(&self) -> Hash {
+ self.trackers_hash
+ }
+
+ pub fn staging_hash(&self) -> Hash {
+ self.staging_hash
+ }
+
+ pub fn digest(&self) -> RpcLayoutDigest {
+ RpcLayoutDigest {
+ current_version: self.current().version,
+ active_versions: self.versions.len(),
+ trackers_hash: self.trackers_hash,
+ staging_hash: self.staging_hash,
+ }
+ }
+
+ // ------------------ helpers for update tracking ---------------
+
+ pub(crate) fn update_trackers(&mut self, local_node_id: Uuid) {
+ // Ensure trackers for this node's values are up-to-date
+
+ // 1. Acknowledge the last layout version which is not currently
+ // locked by an in-progress write operation
+ self.ack_max_free(local_node_id);
+
+ // 2. Assume the data on this node is sync'ed up at least to
+ // the first layout version in the history
+ self.sync_first(local_node_id);
+
+ // 3. Acknowledge everyone has synced up to min(self.sync_map)
+ self.sync_ack(local_node_id);
+
+ debug!("ack_map: {:?}", self.update_trackers.ack_map);
+ debug!("sync_map: {:?}", self.update_trackers.sync_map);
+ debug!("sync_ack_map: {:?}", self.update_trackers.sync_ack_map);
+ }
+
+ fn sync_first(&mut self, local_node_id: Uuid) {
+ let first_version = self.min_stored();
+ self.update(|layout| {
+ layout
+ .update_trackers
+ .sync_map
+ .set_max(local_node_id, first_version)
+ });
+ }
+
+ fn sync_ack(&mut self, local_node_id: Uuid) {
+ let sync_map_min = self.sync_map_min;
+ self.update(|layout| {
+ layout
+ .update_trackers
+ .sync_ack_map
+ .set_max(local_node_id, sync_map_min)
+ });
+ }
+
+ pub(crate) fn ack_max_free(&mut self, local_node_id: Uuid) -> bool {
+ let max_ack = self.max_free_ack();
+ let changed = self.update(|layout| {
+ layout
+ .update_trackers
+ .ack_map
+ .set_max(local_node_id, max_ack)
+ });
+ if changed {
+ info!("ack_until updated to {}", max_ack);
+ }
+ changed
+ }
+
+ pub(crate) fn max_free_ack(&self) -> u64 {
+ self.layout()
+ .versions
+ .iter()
+ .map(|x| x.version)
+ .skip_while(|v| {
+ self.ack_lock
+ .get(v)
+ .map(|x| x.load(Ordering::Relaxed) == 0)
+ .unwrap_or(true)
+ })
+ .next()
+ .unwrap_or(self.current().version)
+ }
+}
diff --git a/src/rpc/layout/history.rs b/src/rpc/layout/history.rs
new file mode 100644
index 00000000..b8cc27da
--- /dev/null
+++ b/src/rpc/layout/history.rs
@@ -0,0 +1,306 @@
+use std::collections::HashSet;
+
+use garage_util::crdt::{Crdt, Lww, LwwMap};
+use garage_util::data::*;
+use garage_util::encode::nonversioned_encode;
+use garage_util::error::*;
+
+use super::*;
+use crate::replication_mode::ReplicationMode;
+
+impl LayoutHistory {
+ pub fn new(replication_factor: usize) -> Self {
+ let version = LayoutVersion::new(replication_factor);
+
+ let staging = LayoutStaging {
+ parameters: Lww::<LayoutParameters>::new(version.parameters),
+ roles: LwwMap::new(),
+ };
+
+ LayoutHistory {
+ versions: vec![version],
+ old_versions: vec![],
+ update_trackers: Default::default(),
+ staging: Lww::raw(0, staging),
+ }
+ }
+
+ // ------------------ who stores what now? ---------------
+
+ pub fn current(&self) -> &LayoutVersion {
+ self.versions.last().as_ref().unwrap()
+ }
+
+ pub fn min_stored(&self) -> u64 {
+ self.versions.first().as_ref().unwrap().version
+ }
+
+ pub fn get_all_nodes(&self) -> Vec<Uuid> {
+ if self.versions.len() == 1 {
+ self.versions[0].all_nodes().to_vec()
+ } else {
+ let set = self
+ .versions
+ .iter()
+ .flat_map(|x| x.all_nodes())
+ .collect::<HashSet<_>>();
+ set.into_iter().copied().collect::<Vec<_>>()
+ }
+ }
+
+ pub(crate) fn get_all_nongateway_nodes(&self) -> Vec<Uuid> {
+ if self.versions.len() == 1 {
+ self.versions[0].nongateway_nodes().to_vec()
+ } else {
+ let set = self
+ .versions
+ .iter()
+ .flat_map(|x| x.nongateway_nodes())
+ .collect::<HashSet<_>>();
+ set.into_iter().copied().collect::<Vec<_>>()
+ }
+ }
+
+ // ---- housekeeping (all invoked by LayoutHelper) ----
+
+ pub(crate) fn keep_current_version_only(&mut self) {
+ while self.versions.len() > 1 {
+ let removed = self.versions.remove(0);
+ self.old_versions.push(removed);
+ }
+ }
+
+ pub(crate) fn cleanup_old_versions(&mut self) {
+ // If there are invalid versions before valid versions, remove them
+ if self.versions.len() > 1 && self.current().check().is_ok() {
+ while self.versions.len() > 1 && self.versions.first().unwrap().check().is_err() {
+ let removed = self.versions.remove(0);
+ info!(
+ "Layout history: pruning old invalid version {}",
+ removed.version
+ );
+ }
+ }
+
+ // If there are old versions that no one is reading from anymore,
+ // remove them (keep them in self.old_versions).
+ // ASSUMPTION: we only care about where nodes in the current layout version
+ // are reading from, as we assume older nodes are being discarded.
+ let current_nodes = &self.current().node_id_vec;
+ let min_version = self.min_stored();
+ let sync_ack_map_min = self
+ .update_trackers
+ .sync_ack_map
+ .min_among(current_nodes, min_version);
+ while self.min_stored() < sync_ack_map_min {
+ assert!(self.versions.len() > 1);
+ let removed = self.versions.remove(0);
+ info!(
+ "Layout history: moving version {} to old_versions",
+ removed.version
+ );
+ self.old_versions.push(removed);
+ }
+
+ while self.old_versions.len() > OLD_VERSION_COUNT {
+ let removed = self.old_versions.remove(0);
+ info!("Layout history: removing old_version {}", removed.version);
+ }
+ }
+
+ pub(crate) fn clamp_update_trackers(&mut self, nodes: &[Uuid]) {
+ let min_v = self.min_stored();
+ for node in nodes {
+ self.update_trackers.ack_map.set_max(*node, min_v);
+ self.update_trackers.sync_map.set_max(*node, min_v);
+ self.update_trackers.sync_ack_map.set_max(*node, min_v);
+ }
+ }
+
+ pub(crate) fn calculate_sync_map_min_with_quorum(
+ &self,
+ replication_mode: ReplicationMode,
+ all_nongateway_nodes: &[Uuid],
+ ) -> u64 {
+ // This function calculates the minimum layout version from which
+ // it is safe to read if we want to maintain read-after-write consistency.
+ // In the general case the computation can be a bit expensive so
+ // we try to optimize it in several ways.
+
+ // If there is only one layout version, we know that's the one
+ // we need to read from.
+ if self.versions.len() == 1 {
+ return self.current().version;
+ }
+
+ let quorum = replication_mode.write_quorum();
+
+ let min_version = self.min_stored();
+ let global_min = self
+ .update_trackers
+ .sync_map
+ .min_among(all_nongateway_nodes, min_version);
+
+ // If the write quorums are equal to the total number of nodes,
+ // i.e. no writes can succeed while they are not written to all nodes,
+ // then we must in all case wait for all nodes to complete a sync.
+ // This is represented by reading from the layout with version
+ // number global_min, the smallest layout version for which all nodes
+ // have completed a sync.
+ if quorum == self.current().replication_factor {
+ return global_min;
+ }
+
+ // In the general case, we need to look at all write sets for all partitions,
+ // and find a safe layout version to read for that partition. We then
+ // take the minimum value among all partition as the safe layout version
+ // to read in all cases (the layout version to which all reads are directed).
+ let mut current_min = self.current().version;
+ let mut sets_done = HashSet::<Vec<Uuid>>::new();
+
+ for (_, p_hash) in self.current().partitions() {
+ for v in self.versions.iter() {
+ if v.version == self.current().version {
+ // We don't care about whether nodes in the latest layout version
+ // have completed a sync or not, as the sync is push-only
+ // and by definition nodes in the latest layout version do not
+ // hold data that must be pushed to nodes in the latest layout
+ // version, since that's the same version (any data that's
+ // already in the latest version is assumed to have been written
+ // by an operation that ensured a quorum of writes within
+ // that version).
+ continue;
+ }
+
+ // Determine set of nodes for partition p in layout version v.
+ // Sort the node set to avoid duplicate computations.
+ let mut set = v
+ .nodes_of(&p_hash, v.replication_factor)
+ .collect::<Vec<Uuid>>();
+ set.sort();
+
+ // If this set was already processed, skip it.
+ if sets_done.contains(&set) {
+ continue;
+ }
+
+ // Find the value of the sync update trackers that is the
+ // highest possible minimum within a quorum of nodes.
+ let mut sync_values = set
+ .iter()
+ .map(|x| self.update_trackers.sync_map.get(x, min_version))
+ .collect::<Vec<_>>();
+ sync_values.sort();
+ let set_min = sync_values[sync_values.len() - quorum];
+ if set_min < current_min {
+ current_min = set_min;
+ }
+ // defavorable case, we know we are at the smallest possible version,
+ // so we can stop early
+ assert!(current_min >= global_min);
+ if current_min == global_min {
+ return current_min;
+ }
+
+ // Add set to already processed sets
+ sets_done.insert(set);
+ }
+ }
+
+ current_min
+ }
+
+ pub(crate) fn calculate_trackers_hash(&self) -> Hash {
+ blake2sum(&nonversioned_encode(&self.update_trackers).unwrap()[..])
+ }
+
+ pub(crate) fn calculate_staging_hash(&self) -> Hash {
+ blake2sum(&nonversioned_encode(&self.staging).unwrap()[..])
+ }
+
+ // ================== updates to layout, public interface ===================
+
+ pub fn merge(&mut self, other: &LayoutHistory) -> bool {
+ let mut changed = false;
+
+ // Add any new versions to history
+ for v2 in other.versions.iter() {
+ if let Some(v1) = self.versions.iter().find(|v| v.version == v2.version) {
+ // Version is already present, check consistency
+ if v1 != v2 {
+ error!("Inconsistent layout histories: different layout compositions for version {}. Your cluster will be broken as long as this layout version is not replaced.", v2.version);
+ }
+ } else if self.versions.iter().all(|v| v.version != v2.version - 1) {
+ error!(
+ "Cannot receive new layout version {}, version {} is missing",
+ v2.version,
+ v2.version - 1
+ );
+ } else {
+ self.versions.push(v2.clone());
+ changed = true;
+ }
+ }
+
+ // Merge trackers
+ let c = self.update_trackers.merge(&other.update_trackers);
+ changed = changed || c;
+
+ // Merge staged layout changes
+ if self.staging != other.staging {
+ let prev_staging = self.staging.clone();
+ self.staging.merge(&other.staging);
+ changed = changed || self.staging != prev_staging;
+ }
+
+ changed
+ }
+
+ pub fn apply_staged_changes(mut self, version: Option<u64>) -> Result<(Self, Message), Error> {
+ match version {
+ None => {
+ let error = r#"
+Please pass the new layout version number to ensure that you are writing the correct version of the cluster layout.
+To know the correct value of the new layout version, invoke `garage layout show` and review the proposed changes.
+ "#;
+ return Err(Error::Message(error.into()));
+ }
+ Some(v) => {
+ if v != self.current().version + 1 {
+ return Err(Error::Message("Invalid new layout version".into()));
+ }
+ }
+ }
+
+ // Compute new version and add it to history
+ let (new_version, msg) = self
+ .current()
+ .clone()
+ .calculate_next_version(self.staging.get())?;
+
+ self.versions.push(new_version);
+ self.cleanup_old_versions();
+
+ // Reset the staged layout changes
+ self.staging.update(LayoutStaging {
+ parameters: self.staging.get().parameters.clone(),
+ roles: LwwMap::new(),
+ });
+
+ Ok((self, msg))
+ }
+
+ pub fn revert_staged_changes(mut self) -> Result<Self, Error> {
+ self.staging.update(LayoutStaging {
+ parameters: Lww::new(self.current().parameters),
+ roles: LwwMap::new(),
+ });
+
+ Ok(self)
+ }
+
+ pub fn check(&self) -> Result<(), String> {
+ // TODO: anything more ?
+ self.current().check()
+ }
+}
diff --git a/src/rpc/layout/manager.rs b/src/rpc/layout/manager.rs
new file mode 100644
index 00000000..6747b79d
--- /dev/null
+++ b/src/rpc/layout/manager.rs
@@ -0,0 +1,378 @@
+use std::collections::HashMap;
+use std::sync::{atomic::Ordering, Arc, Mutex, RwLock, RwLockReadGuard};
+use std::time::Duration;
+
+use tokio::sync::Notify;
+
+use netapp::endpoint::Endpoint;
+use netapp::peering::fullmesh::FullMeshPeeringStrategy;
+use netapp::NodeID;
+
+use garage_util::config::Config;
+use garage_util::data::*;
+use garage_util::error::*;
+use garage_util::persister::Persister;
+
+use super::*;
+use crate::replication_mode::ReplicationMode;
+use crate::rpc_helper::*;
+use crate::system::*;
+
+pub struct LayoutManager {
+ node_id: Uuid,
+ replication_mode: ReplicationMode,
+ persist_cluster_layout: Persister<LayoutHistory>,
+
+ layout: Arc<RwLock<LayoutHelper>>,
+ pub(crate) change_notify: Arc<Notify>,
+
+ table_sync_version: Mutex<HashMap<String, u64>>,
+
+ pub(crate) rpc_helper: RpcHelper,
+ system_endpoint: Arc<Endpoint<SystemRpc, System>>,
+}
+
+impl LayoutManager {
+ pub fn new(
+ config: &Config,
+ node_id: NodeID,
+ system_endpoint: Arc<Endpoint<SystemRpc, System>>,
+ fullmesh: Arc<FullMeshPeeringStrategy>,
+ replication_mode: ReplicationMode,
+ ) -> Result<Arc<Self>, Error> {
+ let replication_factor = replication_mode.replication_factor();
+
+ let persist_cluster_layout: Persister<LayoutHistory> =
+ Persister::new(&config.metadata_dir, "cluster_layout");
+
+ let cluster_layout = match persist_cluster_layout.load() {
+ Ok(x) => {
+ if x.current().replication_factor != replication_mode.replication_factor() {
+ return Err(Error::Message(format!(
+ "Prevous cluster layout has replication factor {}, which is different than the one specified in the config file ({}). The previous cluster layout can be purged, if you know what you are doing, simply by deleting the `cluster_layout` file in your metadata directory.",
+ x.current().replication_factor,
+ replication_factor
+ )));
+ }
+ x
+ }
+ Err(e) => {
+ info!(
+ "No valid previous cluster layout stored ({}), starting fresh.",
+ e
+ );
+ LayoutHistory::new(replication_factor)
+ }
+ };
+
+ let mut cluster_layout =
+ LayoutHelper::new(replication_mode, cluster_layout, Default::default());
+ cluster_layout.update_trackers(node_id.into());
+
+ let layout = Arc::new(RwLock::new(cluster_layout));
+ let change_notify = Arc::new(Notify::new());
+
+ let rpc_helper = RpcHelper::new(
+ node_id.into(),
+ fullmesh,
+ layout.clone(),
+ config.rpc_timeout_msec.map(Duration::from_millis),
+ );
+
+ Ok(Arc::new(Self {
+ node_id: node_id.into(),
+ replication_mode,
+ persist_cluster_layout,
+ layout,
+ change_notify,
+ table_sync_version: Mutex::new(HashMap::new()),
+ system_endpoint,
+ rpc_helper,
+ }))
+ }
+
+ // ---- PUBLIC INTERFACE ----
+
+ pub fn layout(&self) -> RwLockReadGuard<'_, LayoutHelper> {
+ self.layout.read().unwrap()
+ }
+
+ pub async fn update_cluster_layout(
+ self: &Arc<Self>,
+ layout: &LayoutHistory,
+ ) -> Result<(), Error> {
+ self.handle_advertise_cluster_layout(layout).await?;
+ Ok(())
+ }
+
+ pub fn add_table(&self, table_name: &'static str) {
+ let first_version = self.layout().versions.first().unwrap().version;
+
+ self.table_sync_version
+ .lock()
+ .unwrap()
+ .insert(table_name.to_string(), first_version);
+ }
+
+ pub fn sync_table_until(self: &Arc<Self>, table_name: &'static str, version: u64) {
+ let mut table_sync_version = self.table_sync_version.lock().unwrap();
+ *table_sync_version.get_mut(table_name).unwrap() = version;
+ let sync_until = table_sync_version.iter().map(|(_, v)| *v).min().unwrap();
+ drop(table_sync_version);
+
+ let mut layout = self.layout.write().unwrap();
+ if layout.update(|l| l.update_trackers.sync_map.set_max(self.node_id, sync_until)) {
+ info!("sync_until updated to {}", sync_until);
+ self.broadcast_update(SystemRpc::AdvertiseClusterLayoutTrackers(
+ layout.update_trackers.clone(),
+ ));
+ }
+ }
+
+ fn ack_new_version(self: &Arc<Self>) {
+ let mut layout = self.layout.write().unwrap();
+ if layout.ack_max_free(self.node_id) {
+ self.broadcast_update(SystemRpc::AdvertiseClusterLayoutTrackers(
+ layout.update_trackers.clone(),
+ ));
+ }
+ }
+
+ // ---- ACK LOCKING ----
+
+ pub fn write_sets_of(self: &Arc<Self>, position: &Hash) -> WriteLock<Vec<Vec<Uuid>>> {
+ let layout = self.layout();
+ let version = layout.current().version;
+ let nodes = layout.storage_sets_of(position);
+ layout
+ .ack_lock
+ .get(&version)
+ .unwrap()
+ .fetch_add(1, Ordering::Relaxed);
+ WriteLock::new(version, self, nodes)
+ }
+
+ // ---- INTERNALS ---
+
+ fn merge_layout(&self, adv: &LayoutHistory) -> Option<LayoutHistory> {
+ let mut layout = self.layout.write().unwrap();
+ let prev_digest = layout.digest();
+ let prev_layout_check = layout.check().is_ok();
+
+ if !prev_layout_check || adv.check().is_ok() {
+ if layout.update(|l| l.merge(adv)) {
+ layout.update_trackers(self.node_id);
+ if prev_layout_check && layout.check().is_err() {
+ panic!("Merged two correct layouts and got an incorrect layout.");
+ }
+ assert!(layout.digest() != prev_digest);
+ return Some(layout.clone());
+ }
+ }
+
+ None
+ }
+
+ fn merge_layout_trackers(&self, adv: &UpdateTrackers) -> Option<UpdateTrackers> {
+ let mut layout = self.layout.write().unwrap();
+ let prev_digest = layout.digest();
+
+ if layout.update_trackers != *adv {
+ if layout.update(|l| l.update_trackers.merge(adv)) {
+ layout.update_trackers(self.node_id);
+ assert!(layout.digest() != prev_digest);
+ return Some(layout.update_trackers.clone());
+ }
+ }
+
+ None
+ }
+
+ async fn pull_cluster_layout(self: &Arc<Self>, peer: Uuid) {
+ let resp = self
+ .rpc_helper
+ .call(
+ &self.system_endpoint,
+ peer,
+ SystemRpc::PullClusterLayout,
+ RequestStrategy::with_priority(PRIO_HIGH),
+ )
+ .await;
+ if let Ok(SystemRpc::AdvertiseClusterLayout(layout)) = resp {
+ if let Err(e) = self.handle_advertise_cluster_layout(&layout).await {
+ warn!("In pull_cluster_layout: {}", e);
+ }
+ }
+ }
+
+ async fn pull_cluster_layout_trackers(self: &Arc<Self>, peer: Uuid) {
+ let resp = self
+ .rpc_helper
+ .call(
+ &self.system_endpoint,
+ peer,
+ SystemRpc::PullClusterLayoutTrackers,
+ RequestStrategy::with_priority(PRIO_HIGH),
+ )
+ .await;
+ if let Ok(SystemRpc::AdvertiseClusterLayoutTrackers(trackers)) = resp {
+ if let Err(e) = self
+ .handle_advertise_cluster_layout_trackers(&trackers)
+ .await
+ {
+ warn!("In pull_cluster_layout_trackers: {}", e);
+ }
+ }
+ }
+
+ /// Save cluster layout data to disk
+ async fn save_cluster_layout(&self) -> Result<(), Error> {
+ let layout = self.layout.read().unwrap().clone();
+ self.persist_cluster_layout
+ .save_async(&layout)
+ .await
+ .expect("Cannot save current cluster layout");
+ Ok(())
+ }
+
+ fn broadcast_update(self: &Arc<Self>, rpc: SystemRpc) {
+ tokio::spawn({
+ let this = self.clone();
+ async move {
+ if let Err(e) = this
+ .rpc_helper
+ .broadcast(
+ &this.system_endpoint,
+ rpc,
+ RequestStrategy::with_priority(PRIO_HIGH),
+ )
+ .await
+ {
+ warn!("Error while broadcasting new cluster layout: {}", e);
+ }
+ }
+ });
+ }
+
+ // ---- RPC HANDLERS ----
+
+ pub(crate) fn handle_advertise_status(self: &Arc<Self>, from: Uuid, remote: &RpcLayoutDigest) {
+ let local = self.layout().digest();
+ if remote.current_version > local.current_version
+ || remote.active_versions != local.active_versions
+ || remote.staging_hash != local.staging_hash
+ {
+ tokio::spawn({
+ let this = self.clone();
+ async move { this.pull_cluster_layout(from).await }
+ });
+ } else if remote.trackers_hash != local.trackers_hash {
+ tokio::spawn({
+ let this = self.clone();
+ async move { this.pull_cluster_layout_trackers(from).await }
+ });
+ }
+ }
+
+ pub(crate) fn handle_pull_cluster_layout(&self) -> SystemRpc {
+ let layout = self.layout.read().unwrap().clone();
+ SystemRpc::AdvertiseClusterLayout(layout)
+ }
+
+ pub(crate) fn handle_pull_cluster_layout_trackers(&self) -> SystemRpc {
+ let layout = self.layout.read().unwrap();
+ SystemRpc::AdvertiseClusterLayoutTrackers(layout.update_trackers.clone())
+ }
+
+ pub(crate) async fn handle_advertise_cluster_layout(
+ self: &Arc<Self>,
+ adv: &LayoutHistory,
+ ) -> Result<SystemRpc, Error> {
+ debug!(
+ "handle_advertise_cluster_layout: {} versions, last={}, trackers={:?}",
+ adv.versions.len(),
+ adv.current().version,
+ adv.update_trackers
+ );
+
+ if adv.current().replication_factor != self.replication_mode.replication_factor() {
+ let msg = format!(
+ "Received a cluster layout from another node with replication factor {}, which is different from what we have in our configuration ({}). Discarding the cluster layout we received.",
+ adv.current().replication_factor,
+ self.replication_mode.replication_factor()
+ );
+ error!("{}", msg);
+ return Err(Error::Message(msg));
+ }
+
+ if let Some(new_layout) = self.merge_layout(adv) {
+ debug!("handle_advertise_cluster_layout: some changes were added to the current stuff");
+
+ self.change_notify.notify_waiters();
+ self.broadcast_update(SystemRpc::AdvertiseClusterLayout(new_layout));
+ self.save_cluster_layout().await?;
+ }
+
+ Ok(SystemRpc::Ok)
+ }
+
+ pub(crate) async fn handle_advertise_cluster_layout_trackers(
+ self: &Arc<Self>,
+ trackers: &UpdateTrackers,
+ ) -> Result<SystemRpc, Error> {
+ debug!("handle_advertise_cluster_layout_trackers: {:?}", trackers);
+
+ if let Some(new_trackers) = self.merge_layout_trackers(trackers) {
+ self.change_notify.notify_waiters();
+ self.broadcast_update(SystemRpc::AdvertiseClusterLayoutTrackers(new_trackers));
+ self.save_cluster_layout().await?;
+ }
+
+ Ok(SystemRpc::Ok)
+ }
+}
+
+// ---- ack lock ----
+
+pub struct WriteLock<T> {
+ layout_version: u64,
+ layout_manager: Arc<LayoutManager>,
+ value: T,
+}
+
+impl<T> WriteLock<T> {
+ fn new(version: u64, layout_manager: &Arc<LayoutManager>, value: T) -> Self {
+ Self {
+ layout_version: version,
+ layout_manager: layout_manager.clone(),
+ value,
+ }
+ }
+}
+
+impl<T> AsRef<T> for WriteLock<T> {
+ fn as_ref(&self) -> &T {
+ &self.value
+ }
+}
+
+impl<T> AsMut<T> for WriteLock<T> {
+ fn as_mut(&mut self) -> &mut T {
+ &mut self.value
+ }
+}
+
+impl<T> Drop for WriteLock<T> {
+ fn drop(&mut self) {
+ let layout = self.layout_manager.layout(); // acquire read lock
+ if let Some(counter) = layout.ack_lock.get(&self.layout_version) {
+ let prev_lock = counter.fetch_sub(1, Ordering::Relaxed);
+ if prev_lock == 1 && layout.current().version > self.layout_version {
+ drop(layout); // release read lock, write lock will be acquired
+ self.layout_manager.ack_new_version();
+ }
+ } else {
+ error!("Could not find ack lock counter for layout version {}. This probably indicates a bug in Garage.", self.layout_version);
+ }
+ }
+}
diff --git a/src/rpc/layout/mod.rs b/src/rpc/layout/mod.rs
new file mode 100644
index 00000000..33676c37
--- /dev/null
+++ b/src/rpc/layout/mod.rs
@@ -0,0 +1,478 @@
+use std::fmt;
+
+use bytesize::ByteSize;
+
+use garage_util::crdt::{AutoCrdt, Crdt};
+use garage_util::data::Uuid;
+
+mod graph_algo;
+mod helper;
+mod history;
+mod version;
+
+#[cfg(test)]
+mod test;
+
+pub mod manager;
+
+// ---- re-exports ----
+
+pub use helper::{LayoutHelper, RpcLayoutDigest, SyncLayoutDigest};
+pub use manager::WriteLock;
+pub use version::*;
+
+// ---- defines: partitions ----
+
+/// A partition id, which is stored on 16 bits
+/// i.e. we have up to 2**16 partitions.
+/// (in practice we have exactly 2**PARTITION_BITS partitions)
+pub type Partition = u16;
+
+// TODO: make this constant parametrizable in the config file
+// For deployments with many nodes it might make sense to bump
+// it up to 10.
+// Maximum value : 16
+/// How many bits from the hash are used to make partitions. Higher numbers means more fairness in
+/// presence of numerous nodes, but exponentially bigger ring. Max 16
+pub const PARTITION_BITS: usize = 8;
+
+const NB_PARTITIONS: usize = 1usize << PARTITION_BITS;
+
+// ---- defines: nodes ----
+
+// Type to store compactly the id of a node in the system
+// Change this to u16 the day we want to have more than 256 nodes in a cluster
+pub type CompactNodeType = u8;
+pub const MAX_NODE_NUMBER: usize = 256;
+
+// ======== actual data structures for the layout data ========
+// ======== that is persisted to disk ========
+// some small utility impls are at the end of this file,
+// but most of the code that actually computes stuff is in
+// version.rs, history.rs and helper.rs
+
+mod v08 {
+ use crate::layout::CompactNodeType;
+ use garage_util::crdt::LwwMap;
+ use garage_util::data::{Hash, Uuid};
+ use serde::{Deserialize, Serialize};
+
+ /// The layout of the cluster, i.e. the list of roles
+ /// which are assigned to each cluster node
+ #[derive(Clone, Debug, Serialize, Deserialize)]
+ pub struct ClusterLayout {
+ pub version: u64,
+
+ pub replication_factor: usize,
+ pub roles: LwwMap<Uuid, NodeRoleV>,
+
+ // see comments in v010::ClusterLayout
+ pub node_id_vec: Vec<Uuid>,
+ #[serde(with = "serde_bytes")]
+ pub ring_assignation_data: Vec<CompactNodeType>,
+
+ /// Role changes which are staged for the next version of the layout
+ pub staging: LwwMap<Uuid, NodeRoleV>,
+ pub staging_hash: Hash,
+ }
+
+ #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Debug, Serialize, Deserialize)]
+ pub struct NodeRoleV(pub Option<NodeRole>);
+
+ /// The user-assigned roles of cluster nodes
+ #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Debug, Serialize, Deserialize)]
+ pub struct NodeRole {
+ /// Datacenter at which this entry belong. This information is used to
+ /// perform a better geodistribution
+ pub zone: String,
+ /// The capacity of the node
+ /// If this is set to None, the node does not participate in storing data for the system
+ /// and is only active as an API gateway to other nodes
+ pub capacity: Option<u64>,
+ /// A set of tags to recognize the node
+ pub tags: Vec<String>,
+ }
+
+ impl garage_util::migrate::InitialFormat for ClusterLayout {}
+}
+
+mod v09 {
+ use super::v08;
+ use crate::layout::CompactNodeType;
+ use garage_util::crdt::{Lww, LwwMap};
+ use garage_util::data::{Hash, Uuid};
+ use serde::{Deserialize, Serialize};
+ pub use v08::{NodeRole, NodeRoleV};
+
+ /// The layout of the cluster, i.e. the list of roles
+ /// which are assigned to each cluster node
+ #[derive(Clone, Debug, Serialize, Deserialize)]
+ pub struct ClusterLayout {
+ pub version: u64,
+
+ pub replication_factor: usize,
+
+ /// This attribute is only used to retain the previously computed partition size,
+ /// to know to what extent does it change with the layout update.
+ pub partition_size: u64,
+ /// Parameters used to compute the assignment currently given by
+ /// ring_assignment_data
+ pub parameters: LayoutParameters,
+
+ pub roles: LwwMap<Uuid, NodeRoleV>,
+
+ // see comments in v010::ClusterLayout
+ pub node_id_vec: Vec<Uuid>,
+ #[serde(with = "serde_bytes")]
+ pub ring_assignment_data: Vec<CompactNodeType>,
+
+ /// Parameters to be used in the next partition assignment computation.
+ pub staging_parameters: Lww<LayoutParameters>,
+ /// Role changes which are staged for the next version of the layout
+ pub staging_roles: LwwMap<Uuid, NodeRoleV>,
+ pub staging_hash: Hash,
+ }
+
+ /// This struct is used to set the parameters to be used in the assignment computation
+ /// algorithm. It is stored as a Crdt.
+ #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Debug, Serialize, Deserialize)]
+ pub struct LayoutParameters {
+ pub zone_redundancy: ZoneRedundancy,
+ }
+
+ /// Zone redundancy: if set to AtLeast(x), the layout calculation will aim to store copies
+ /// of each partition on at least that number of different zones.
+ /// Otherwise, copies will be stored on the maximum possible number of zones.
+ #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Debug, Serialize, Deserialize)]
+ pub enum ZoneRedundancy {
+ AtLeast(usize),
+ Maximum,
+ }
+
+ impl garage_util::migrate::Migrate for ClusterLayout {
+ const VERSION_MARKER: &'static [u8] = b"G09layout";
+
+ type Previous = v08::ClusterLayout;
+
+ fn migrate(previous: Self::Previous) -> Self {
+ use itertools::Itertools;
+
+ // In the old layout, capacities are in an arbitrary unit,
+ // but in the new layout they are in bytes.
+ // Here we arbitrarily multiply everything by 1G,
+ // such that 1 old capacity unit = 1GB in the new units.
+ // This is totally arbitrary and won't work for most users.
+ let cap_mul = 1024 * 1024 * 1024;
+ let roles = multiply_all_capacities(previous.roles, cap_mul);
+ let staging_roles = multiply_all_capacities(previous.staging, cap_mul);
+ let node_id_vec = previous.node_id_vec;
+
+ // Determine partition size
+ let mut tmp = previous.ring_assignation_data.clone();
+ tmp.sort();
+ let partition_size = tmp
+ .into_iter()
+ .dedup_with_count()
+ .map(|(npart, node)| {
+ roles
+ .get(&node_id_vec[node as usize])
+ .and_then(|p| p.0.as_ref().and_then(|r| r.capacity))
+ .unwrap_or(0) / npart as u64
+ })
+ .min()
+ .unwrap_or(0);
+
+ // By default, zone_redundancy is maximum possible value
+ let parameters = LayoutParameters {
+ zone_redundancy: ZoneRedundancy::Maximum,
+ };
+
+ Self {
+ version: previous.version,
+ replication_factor: previous.replication_factor,
+ partition_size,
+ parameters,
+ roles,
+ node_id_vec,
+ ring_assignment_data: previous.ring_assignation_data,
+ staging_parameters: Lww::new(parameters),
+ staging_roles,
+ staging_hash: [0u8; 32].into(), // will be set in the next migration
+ }
+ }
+ }
+
+ fn multiply_all_capacities(
+ old_roles: LwwMap<Uuid, NodeRoleV>,
+ mul: u64,
+ ) -> LwwMap<Uuid, NodeRoleV> {
+ let mut new_roles = LwwMap::new();
+ for (node, ts, role) in old_roles.items() {
+ let mut role = role.clone();
+ if let NodeRoleV(Some(NodeRole {
+ capacity: Some(ref mut cap),
+ ..
+ })) = role
+ {
+ *cap *= mul;
+ }
+ new_roles.merge_raw(node, *ts, &role);
+ }
+ new_roles
+ }
+}
+
+mod v010 {
+ use super::v09;
+ use crate::layout::CompactNodeType;
+ use garage_util::crdt::{Lww, LwwMap};
+ use garage_util::data::Uuid;
+ use serde::{Deserialize, Serialize};
+ use std::collections::BTreeMap;
+ pub use v09::{LayoutParameters, NodeRole, NodeRoleV, ZoneRedundancy};
+
+ /// Number of old (non-live) versions to keep, see LayoutHistory::old_versions
+ pub const OLD_VERSION_COUNT: usize = 5;
+
+ /// The history of cluster layouts, with trackers to keep a record
+ /// of which nodes are up-to-date to current cluster data
+ #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+ pub struct LayoutHistory {
+ /// The versions currently in use in the cluster
+ pub versions: Vec<LayoutVersion>,
+ /// At most 5 of the previous versions, not used by the garage_table
+ /// module, but usefull for the garage_block module to find data blocks
+ /// that have not yet been moved
+ pub old_versions: Vec<LayoutVersion>,
+
+ /// Update trackers
+ pub update_trackers: UpdateTrackers,
+
+ /// Staged changes for the next version
+ pub staging: Lww<LayoutStaging>,
+ }
+
+ /// A version of the layout of the cluster, i.e. the list of roles
+ /// which are assigned to each cluster node
+ #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+ pub struct LayoutVersion {
+ /// The number of this version
+ pub version: u64,
+
+ /// Roles assigned to nodes in this version
+ pub roles: LwwMap<Uuid, NodeRoleV>,
+ /// Parameters used to compute the assignment currently given by
+ /// ring_assignment_data
+ pub parameters: LayoutParameters,
+
+ /// The number of replicas for each data partition
+ pub replication_factor: usize,
+ /// This attribute is only used to retain the previously computed partition size,
+ /// to know to what extent does it change with the layout update.
+ pub partition_size: u64,
+
+ /// node_id_vec: a vector of node IDs with a role assigned
+ /// in the system (this includes gateway nodes).
+ /// The order here is different than the vec stored by `roles`, because:
+ /// 1. non-gateway nodes are first so that they have lower numbers
+ /// 2. nodes that don't have a role are excluded (but they need to
+ /// stay in the CRDT as tombstones)
+ pub node_id_vec: Vec<Uuid>,
+ /// number of non-gateway nodes, which are the first ids in node_id_vec
+ pub nongateway_node_count: usize,
+ /// The assignation of data partitions to nodes, the values
+ /// are indices in node_id_vec
+ #[serde(with = "serde_bytes")]
+ pub ring_assignment_data: Vec<CompactNodeType>,
+ }
+
+ /// The staged changes for the next layout version
+ #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+ pub struct LayoutStaging {
+ /// Parameters to be used in the next partition assignment computation.
+ pub parameters: Lww<LayoutParameters>,
+ /// Role changes which are staged for the next version of the layout
+ pub roles: LwwMap<Uuid, NodeRoleV>,
+ }
+
+ /// The tracker of acknowlegments and data syncs around the cluster
+ #[derive(Clone, Debug, Serialize, Deserialize, Default, PartialEq)]
+ pub struct UpdateTrackers {
+ /// The highest layout version number each node has ack'ed
+ pub ack_map: UpdateTracker,
+ /// The highest layout version number each node has synced data for
+ pub sync_map: UpdateTracker,
+ /// The highest layout version number each node has
+ /// ack'ed that all other nodes have synced data for
+ pub sync_ack_map: UpdateTracker,
+ }
+
+ /// Generic update tracker struct
+ #[derive(Clone, Debug, Serialize, Deserialize, Default, PartialEq)]
+ pub struct UpdateTracker(pub BTreeMap<Uuid, u64>);
+
+ impl garage_util::migrate::Migrate for LayoutHistory {
+ const VERSION_MARKER: &'static [u8] = b"G010lh";
+
+ type Previous = v09::ClusterLayout;
+
+ fn migrate(previous: Self::Previous) -> Self {
+ let nongateway_node_count = previous
+ .node_id_vec
+ .iter()
+ .enumerate()
+ .filter(|(_, uuid)| {
+ let role = previous.roles.get(uuid);
+ matches!(role, Some(NodeRoleV(Some(role))) if role.capacity.is_some())
+ })
+ .map(|(i, _)| i + 1)
+ .max()
+ .unwrap_or(0);
+
+ let version = LayoutVersion {
+ version: previous.version,
+ replication_factor: previous.replication_factor,
+ partition_size: previous.partition_size,
+ parameters: previous.parameters,
+ roles: previous.roles,
+ node_id_vec: previous.node_id_vec,
+ nongateway_node_count,
+ ring_assignment_data: previous.ring_assignment_data,
+ };
+ let update_tracker = UpdateTracker(
+ version
+ .nongateway_nodes()
+ .iter()
+ .copied()
+ .map(|x| (x, version.version))
+ .collect::<BTreeMap<Uuid, u64>>(),
+ );
+ let staging = LayoutStaging {
+ parameters: previous.staging_parameters,
+ roles: previous.staging_roles,
+ };
+ Self {
+ versions: vec![version],
+ old_versions: vec![],
+ update_trackers: UpdateTrackers {
+ ack_map: update_tracker.clone(),
+ sync_map: update_tracker.clone(),
+ sync_ack_map: update_tracker,
+ },
+ staging: Lww::raw(previous.version, staging),
+ }
+ }
+ }
+}
+
+pub use v010::*;
+
+// ---- utility functions ----
+
+impl AutoCrdt for LayoutParameters {
+ const WARN_IF_DIFFERENT: bool = true;
+}
+
+impl AutoCrdt for NodeRoleV {
+ const WARN_IF_DIFFERENT: bool = true;
+}
+
+impl Crdt for LayoutStaging {
+ fn merge(&mut self, other: &LayoutStaging) {
+ self.parameters.merge(&other.parameters);
+ self.roles.merge(&other.roles);
+ }
+}
+
+impl NodeRole {
+ pub fn capacity_string(&self) -> String {
+ match self.capacity {
+ Some(c) => ByteSize::b(c).to_string_as(false),
+ None => "gateway".to_string(),
+ }
+ }
+
+ pub fn tags_string(&self) -> String {
+ self.tags.join(",")
+ }
+}
+
+impl fmt::Display for ZoneRedundancy {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match self {
+ ZoneRedundancy::Maximum => write!(f, "maximum"),
+ ZoneRedundancy::AtLeast(x) => write!(f, "{}", x),
+ }
+ }
+}
+
+impl core::str::FromStr for ZoneRedundancy {
+ type Err = &'static str;
+ fn from_str(s: &str) -> Result<Self, Self::Err> {
+ match s {
+ "none" | "max" | "maximum" => Ok(ZoneRedundancy::Maximum),
+ x => {
+ let v = x
+ .parse::<usize>()
+ .map_err(|_| "zone redundancy must be 'none'/'max' or an integer")?;
+ Ok(ZoneRedundancy::AtLeast(v))
+ }
+ }
+ }
+}
+
+impl UpdateTracker {
+ fn merge(&mut self, other: &UpdateTracker) -> bool {
+ let mut changed = false;
+ for (k, v) in other.0.iter() {
+ if let Some(v_mut) = self.0.get_mut(k) {
+ if *v > *v_mut {
+ *v_mut = *v;
+ changed = true;
+ }
+ } else {
+ self.0.insert(*k, *v);
+ changed = true;
+ }
+ }
+ changed
+ }
+
+ /// This bumps the update tracker for a given node up to the specified value.
+ /// This has potential impacts on the correctness of Garage and should only
+ /// be used in very specific circumstances.
+ pub fn set_max(&mut self, peer: Uuid, value: u64) -> bool {
+ match self.0.get_mut(&peer) {
+ Some(e) if *e < value => {
+ *e = value;
+ true
+ }
+ None => {
+ self.0.insert(peer, value);
+ true
+ }
+ _ => false,
+ }
+ }
+
+ pub(crate) fn min_among(&self, storage_nodes: &[Uuid], min_version: u64) -> u64 {
+ storage_nodes
+ .iter()
+ .map(|x| self.get(x, min_version))
+ .min()
+ .unwrap_or(min_version)
+ }
+
+ pub fn get(&self, node: &Uuid, min_version: u64) -> u64 {
+ self.0.get(node).copied().unwrap_or(min_version)
+ }
+}
+
+impl UpdateTrackers {
+ pub(crate) fn merge(&mut self, other: &UpdateTrackers) -> bool {
+ let c1 = self.ack_map.merge(&other.ack_map);
+ let c2 = self.sync_map.merge(&other.sync_map);
+ let c3 = self.sync_ack_map.merge(&other.sync_ack_map);
+ c1 || c2 || c3
+ }
+}
diff --git a/src/rpc/layout/test.rs b/src/rpc/layout/test.rs
new file mode 100644
index 00000000..88eb518e
--- /dev/null
+++ b/src/rpc/layout/test.rs
@@ -0,0 +1,157 @@
+use std::cmp::min;
+use std::collections::HashMap;
+
+use garage_util::crdt::Crdt;
+use garage_util::error::*;
+
+use crate::layout::*;
+
+// This function checks that the partition size S computed is at least better than the
+// one given by a very naive algorithm. To do so, we try to run the naive algorithm
+// assuming a partion size of S+1. If we succed, it means that the optimal assignment
+// was not optimal. The naive algorithm is the following :
+// - we compute the max number of partitions associated to every node, capped at the
+// partition number. It gives the number of tokens of every node.
+// - every zone has a number of tokens equal to the sum of the tokens of its nodes.
+// - we cycle over the partitions and associate zone tokens while respecting the
+// zone redundancy constraint.
+// NOTE: the naive algorithm is not optimal. Counter example:
+// take nb_partition = 3 ; replication_factor = 5; redundancy = 4;
+// number of tokens by zone : (A, 4), (B,1), (C,4), (D, 4), (E, 2)
+// With these parameters, the naive algo fails, whereas there is a solution:
+// (A,A,C,D,E) , (A,B,C,D,D) (A,C,C,D,E)
+fn check_against_naive(cl: &LayoutVersion) -> Result<bool, Error> {
+ let over_size = cl.partition_size + 1;
+ let mut zone_token = HashMap::<String, usize>::new();
+
+ let (zones, zone_to_id) = cl.generate_nongateway_zone_ids()?;
+
+ if zones.is_empty() {
+ return Ok(false);
+ }
+
+ for z in zones.iter() {
+ zone_token.insert(z.clone(), 0);
+ }
+ for uuid in cl.nongateway_nodes() {
+ let z = cl.expect_get_node_zone(&uuid);
+ let c = cl.expect_get_node_capacity(&uuid);
+ zone_token.insert(
+ z.to_string(),
+ zone_token[z] + min(NB_PARTITIONS, (c / over_size) as usize),
+ );
+ }
+
+ // For every partition, we count the number of zone already associated and
+ // the name of the last zone associated
+
+ let mut id_zone_token = vec![0; zones.len()];
+ for (z, t) in zone_token.iter() {
+ id_zone_token[zone_to_id[z]] = *t;
+ }
+
+ let mut nb_token = vec![0; NB_PARTITIONS];
+ let mut last_zone = vec![zones.len(); NB_PARTITIONS];
+
+ let mut curr_zone = 0;
+
+ let redundancy = cl.effective_zone_redundancy();
+
+ for replic in 0..cl.replication_factor {
+ for p in 0..NB_PARTITIONS {
+ while id_zone_token[curr_zone] == 0
+ || (last_zone[p] == curr_zone
+ && redundancy - nb_token[p] <= cl.replication_factor - replic)
+ {
+ curr_zone += 1;
+ if curr_zone >= zones.len() {
+ return Ok(true);
+ }
+ }
+ id_zone_token[curr_zone] -= 1;
+ if last_zone[p] != curr_zone {
+ nb_token[p] += 1;
+ last_zone[p] = curr_zone;
+ }
+ }
+ }
+
+ return Ok(false);
+}
+
+fn show_msg(msg: &Message) {
+ for s in msg.iter() {
+ println!("{}", s);
+ }
+}
+
+fn update_layout(
+ cl: &mut LayoutHistory,
+ node_capacity_vec: &[u64],
+ node_zone_vec: &[&'static str],
+ zone_redundancy: usize,
+) {
+ let staging = cl.staging.get_mut();
+
+ for (i, (capacity, zone)) in node_capacity_vec
+ .iter()
+ .zip(node_zone_vec.iter())
+ .enumerate()
+ {
+ let node_id = [i as u8; 32].into();
+
+ let update = staging.roles.update_mutator(
+ node_id,
+ NodeRoleV(Some(NodeRole {
+ zone: zone.to_string(),
+ capacity: Some(*capacity),
+ tags: (vec![]),
+ })),
+ );
+ staging.roles.merge(&update);
+ }
+ staging.parameters.update(LayoutParameters {
+ zone_redundancy: ZoneRedundancy::AtLeast(zone_redundancy),
+ });
+}
+
+#[test]
+fn test_assignment() {
+ let mut node_capacity_vec = vec![4000, 1000, 2000];
+ let mut node_zone_vec = vec!["A", "B", "C"];
+
+ let mut cl = LayoutHistory::new(3);
+ update_layout(&mut cl, &node_capacity_vec, &node_zone_vec, 3);
+ let v = cl.current().version;
+ let (mut cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
+ show_msg(&msg);
+ assert_eq!(cl.check(), Ok(()));
+ assert!(check_against_naive(cl.current()).unwrap());
+
+ node_capacity_vec = vec![4000, 1000, 1000, 3000, 1000, 1000, 2000, 10000, 2000];
+ node_zone_vec = vec!["A", "B", "C", "C", "C", "B", "G", "H", "I"];
+ update_layout(&mut cl, &node_capacity_vec, &node_zone_vec, 2);
+ let v = cl.current().version;
+ let (mut cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
+ show_msg(&msg);
+ assert_eq!(cl.check(), Ok(()));
+ assert!(check_against_naive(cl.current()).unwrap());
+
+ node_capacity_vec = vec![4000, 1000, 2000, 7000, 1000, 1000, 2000, 10000, 2000];
+ update_layout(&mut cl, &node_capacity_vec, &node_zone_vec, 3);
+ let v = cl.current().version;
+ let (mut cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
+ show_msg(&msg);
+ assert_eq!(cl.check(), Ok(()));
+ assert!(check_against_naive(cl.current()).unwrap());
+
+ node_capacity_vec = vec![
+ 4000000, 4000000, 2000000, 7000000, 1000000, 9000000, 2000000, 10000, 2000000,
+ ];
+ update_layout(&mut cl, &node_capacity_vec, &node_zone_vec, 1);
+ let v = cl.current().version;
+ let (cl, msg) = cl.apply_staged_changes(Some(v + 1)).unwrap();
+ show_msg(&msg);
+ assert_eq!(cl.check(), Ok(()));
+ assert!(check_against_naive(cl.current()).unwrap());
+}
diff --git a/src/rpc/layout/version.rs b/src/rpc/layout/version.rs
new file mode 100644
index 00000000..ee4b2821
--- /dev/null
+++ b/src/rpc/layout/version.rs
@@ -0,0 +1,846 @@
+use std::collections::HashMap;
+use std::collections::HashSet;
+use std::convert::TryInto;
+
+use bytesize::ByteSize;
+use itertools::Itertools;
+
+use garage_util::crdt::{Crdt, LwwMap};
+use garage_util::data::*;
+use garage_util::error::*;
+
+use super::graph_algo::*;
+use super::*;
+
+// The Message type will be used to collect information on the algorithm.
+pub type Message = Vec<String>;
+
+impl LayoutVersion {
+ pub fn new(replication_factor: usize) -> Self {
+ // We set the default zone redundancy to be Maximum, meaning that the maximum
+ // possible value will be used depending on the cluster topology
+ let parameters = LayoutParameters {
+ zone_redundancy: ZoneRedundancy::Maximum,
+ };
+
+ LayoutVersion {
+ version: 0,
+ replication_factor,
+ partition_size: 0,
+ roles: LwwMap::new(),
+ node_id_vec: Vec::new(),
+ nongateway_node_count: 0,
+ ring_assignment_data: Vec::new(),
+ parameters,
+ }
+ }
+
+ // ===================== accessors ======================
+
+ /// Returns a list of IDs of nodes that have a role in this
+ /// version of the cluster layout, including gateway nodes
+ pub fn all_nodes(&self) -> &[Uuid] {
+ &self.node_id_vec[..]
+ }
+
+ /// Returns a list of IDs of nodes that have a storage capacity
+ /// assigned in this version of the cluster layout
+ pub fn nongateway_nodes(&self) -> &[Uuid] {
+ &self.node_id_vec[..self.nongateway_node_count]
+ }
+
+ /// Returns the role of a node in the layout, if it has one
+ pub fn node_role(&self, node: &Uuid) -> Option<&NodeRole> {
+ match self.roles.get(node) {
+ Some(NodeRoleV(Some(v))) => Some(v),
+ _ => None,
+ }
+ }
+
+ /// Returns the capacity of a node in the layout, if it has one
+ pub fn get_node_capacity(&self, uuid: &Uuid) -> Option<u64> {
+ match self.node_role(uuid) {
+ Some(NodeRole {
+ capacity: Some(cap),
+ zone: _,
+ tags: _,
+ }) => Some(*cap),
+ _ => None,
+ }
+ }
+
+ /// Given a node uuids, this function returns the label of its zone if it has one
+ pub fn get_node_zone(&self, uuid: &Uuid) -> Option<&str> {
+ match self.node_role(uuid) {
+ Some(role) => Some(&role.zone),
+ _ => None,
+ }
+ }
+
+ /// Returns the number of partitions associated to this node in the ring
+ pub fn get_node_usage(&self, uuid: &Uuid) -> Result<usize, Error> {
+ for (i, id) in self.node_id_vec.iter().enumerate() {
+ if id == uuid {
+ let mut count = 0;
+ for nod in self.ring_assignment_data.iter() {
+ if i as u8 == *nod {
+ count += 1
+ }
+ }
+ return Ok(count);
+ }
+ }
+ Err(Error::Message(
+ "The Uuid does not correspond to a node present in the \
+ cluster or this node does not have a positive capacity."
+ .into(),
+ ))
+ }
+
+ /// Get the partition in which data would fall on
+ pub fn partition_of(&self, position: &Hash) -> Partition {
+ let top = u16::from_be_bytes(position.as_slice()[0..2].try_into().unwrap());
+ top >> (16 - PARTITION_BITS)
+ }
+
+ /// Get the list of partitions and the first hash of a partition key that would fall in it
+ pub fn partitions(&self) -> impl Iterator<Item = (Partition, Hash)> + '_ {
+ (0..(1 << PARTITION_BITS)).map(|i| {
+ let top = (i as u16) << (16 - PARTITION_BITS);
+ let mut location = [0u8; 32];
+ location[..2].copy_from_slice(&u16::to_be_bytes(top)[..]);
+ (i as u16, Hash::from(location))
+ })
+ }
+
+ /// Return the n servers in which data for this hash should be replicated
+ pub fn nodes_of(&self, position: &Hash, n: usize) -> impl Iterator<Item = Uuid> + '_ {
+ assert_eq!(n, self.replication_factor);
+
+ let data = &self.ring_assignment_data;
+
+ let partition_nodes = if data.len() == self.replication_factor * (1 << PARTITION_BITS) {
+ let partition_idx = self.partition_of(position) as usize;
+ let partition_start = partition_idx * self.replication_factor;
+ let partition_end = (partition_idx + 1) * self.replication_factor;
+ &data[partition_start..partition_end]
+ } else {
+ warn!("Ring not yet ready, read/writes will be lost!");
+ &[]
+ };
+
+ partition_nodes
+ .iter()
+ .map(move |i| self.node_id_vec[*i as usize])
+ }
+
+ // ===================== internal information extractors ======================
+
+ pub(crate) fn expect_get_node_capacity(&self, uuid: &Uuid) -> u64 {
+ self.get_node_capacity(uuid)
+ .expect("non-gateway node with zero capacity")
+ }
+
+ pub(crate) fn expect_get_node_zone(&self, uuid: &Uuid) -> &str {
+ self.get_node_zone(uuid).expect("node without a zone")
+ }
+
+ /// Returns the sum of capacities of non gateway nodes in the cluster
+ fn get_total_capacity(&self) -> u64 {
+ let mut total_capacity = 0;
+ for uuid in self.nongateway_nodes() {
+ total_capacity += self.expect_get_node_capacity(uuid);
+ }
+ total_capacity
+ }
+
+ /// Returns the effective value of the zone_redundancy parameter
+ pub(crate) fn effective_zone_redundancy(&self) -> usize {
+ match self.parameters.zone_redundancy {
+ ZoneRedundancy::AtLeast(v) => v,
+ ZoneRedundancy::Maximum => {
+ let n_zones = self
+ .roles
+ .items()
+ .iter()
+ .filter_map(|(_, _, role)| role.0.as_ref().map(|x| x.zone.as_str()))
+ .collect::<HashSet<&str>>()
+ .len();
+ std::cmp::min(n_zones, self.replication_factor)
+ }
+ }
+ }
+
+ /// Check a cluster layout for internal consistency
+ /// (assignment, roles, parameters, partition size)
+ /// returns true if consistent, false if error
+ pub fn check(&self) -> Result<(), String> {
+ // Check that the assignment data has the correct length
+ let expected_assignment_data_len = (1 << PARTITION_BITS) * self.replication_factor;
+ if self.ring_assignment_data.len() != expected_assignment_data_len {
+ return Err(format!(
+ "ring_assignment_data has incorrect length {} instead of {}",
+ self.ring_assignment_data.len(),
+ expected_assignment_data_len
+ ));
+ }
+
+ // Check that node_id_vec contains the correct list of nodes
+ let mut expected_nodes = self
+ .roles
+ .items()
+ .iter()
+ .filter(|(_, _, v)| v.0.is_some())
+ .map(|(id, _, _)| *id)
+ .collect::<Vec<_>>();
+ expected_nodes.sort();
+ let mut node_id_vec = self.node_id_vec.clone();
+ node_id_vec.sort();
+ if expected_nodes != node_id_vec {
+ return Err(format!("node_id_vec does not contain the correct set of nodes\nnode_id_vec: {:?}\nexpected: {:?}", node_id_vec, expected_nodes));
+ }
+
+ // Check that the assigned nodes are correct identifiers
+ // of nodes that are assigned a role
+ // and that role is not the role of a gateway nodes
+ for x in self.ring_assignment_data.iter() {
+ if *x as usize >= self.node_id_vec.len() {
+ return Err(format!(
+ "ring_assignment_data contains invalid node id {}",
+ *x
+ ));
+ }
+ let node = self.node_id_vec[*x as usize];
+ match self.roles.get(&node) {
+ Some(NodeRoleV(Some(x))) if x.capacity.is_some() => (),
+ _ => return Err("ring_assignment_data contains id of a gateway node".into()),
+ }
+ }
+
+ // Check that every partition is associated to distinct nodes
+ let zone_redundancy = self.effective_zone_redundancy();
+ let rf = self.replication_factor;
+ for p in 0..(1 << PARTITION_BITS) {
+ let nodes_of_p = self.ring_assignment_data[rf * p..rf * (p + 1)].to_vec();
+ if nodes_of_p.iter().unique().count() != rf {
+ return Err(format!("partition does not contain {} unique node ids", rf));
+ }
+ // Check that every partition is spread over at least zone_redundancy zones.
+ let zones_of_p = nodes_of_p
+ .iter()
+ .map(|n| self.expect_get_node_zone(&self.node_id_vec[*n as usize]))
+ .collect::<Vec<_>>();
+ if zones_of_p.iter().unique().count() < zone_redundancy {
+ return Err(format!(
+ "nodes of partition are in less than {} distinct zones",
+ zone_redundancy
+ ));
+ }
+ }
+
+ // Check that the nodes capacities is consistent with the stored partitions
+ let mut node_usage = vec![0; MAX_NODE_NUMBER];
+ for n in self.ring_assignment_data.iter() {
+ node_usage[*n as usize] += 1;
+ }
+ for (n, usage) in node_usage.iter().enumerate() {
+ if *usage > 0 {
+ let uuid = self.node_id_vec[n];
+ let partusage = usage * self.partition_size;
+ let nodecap = self.expect_get_node_capacity(&uuid);
+ if partusage > nodecap {
+ return Err(format!(
+ "node usage ({}) is bigger than node capacity ({})",
+ usage * self.partition_size,
+ nodecap
+ ));
+ }
+ }
+ }
+
+ // Check that the partition size stored is the one computed by the asignation
+ // algorithm.
+ let cl2 = self.clone();
+ let (_, zone_to_id) = cl2.generate_nongateway_zone_ids().unwrap();
+ match cl2.compute_optimal_partition_size(&zone_to_id, zone_redundancy) {
+ Ok(s) if s != self.partition_size => {
+ return Err(format!(
+ "partition_size ({}) is different than optimal value ({})",
+ self.partition_size, s
+ ))
+ }
+ Err(e) => return Err(format!("could not calculate optimal partition size: {}", e)),
+ _ => (),
+ }
+
+ Ok(())
+ }
+
+ // ================== updates to layout, internals ===================
+
+ pub(crate) fn calculate_next_version(
+ mut self,
+ staging: &LayoutStaging,
+ ) -> Result<(Self, Message), Error> {
+ self.version += 1;
+
+ self.roles.merge(&staging.roles);
+ self.roles.retain(|(_, _, v)| v.0.is_some());
+ self.parameters = *staging.parameters.get();
+
+ let msg = self.calculate_partition_assignment()?;
+
+ Ok((self, msg))
+ }
+
+ /// This function calculates a new partition-to-node assignment.
+ /// The computed assignment respects the node replication factor
+ /// and the zone redundancy parameter It maximizes the capacity of a
+ /// partition (assuming all partitions have the same size).
+ /// Among such optimal assignment, it minimizes the distance to
+ /// the former assignment (if any) to minimize the amount of
+ /// data to be moved.
+ /// Staged role changes must be merged with nodes roles before calling this function,
+ /// hence it must only be called from apply_staged_changes() and hence is not public.
+ fn calculate_partition_assignment(&mut self) -> Result<Message, Error> {
+ // We update the node ids, since the node role list might have changed with the
+ // changes in the layout. We retrieve the old_assignment reframed with new ids
+ let old_assignment_opt = self.update_node_id_vec()?;
+
+ let zone_redundancy = self.effective_zone_redundancy();
+
+ let mut msg = Message::new();
+ msg.push("==== COMPUTATION OF A NEW PARTITION ASSIGNATION ====".into());
+ msg.push("".into());
+ msg.push(format!(
+ "Partitions are \
+ replicated {} times on at least {} distinct zones.",
+ self.replication_factor, zone_redundancy
+ ));
+
+ // We generate for once numerical ids for the zones of non gateway nodes,
+ // to use them as indices in the flow graphs.
+ let (id_to_zone, zone_to_id) = self.generate_nongateway_zone_ids()?;
+
+ if self.nongateway_nodes().len() < self.replication_factor {
+ return Err(Error::Message(format!(
+ "The number of nodes with positive \
+ capacity ({}) is smaller than the replication factor ({}).",
+ self.nongateway_nodes().len(),
+ self.replication_factor
+ )));
+ }
+ if id_to_zone.len() < zone_redundancy {
+ return Err(Error::Message(format!(
+ "The number of zones with non-gateway \
+ nodes ({}) is smaller than the redundancy parameter ({})",
+ id_to_zone.len(),
+ zone_redundancy
+ )));
+ }
+
+ // We compute the optimal partition size
+ // Capacities should be given in a unit so that partition size is at least 100.
+ // In this case, integer rounding plays a marginal role in the percentages of
+ // optimality.
+ let partition_size = self.compute_optimal_partition_size(&zone_to_id, zone_redundancy)?;
+
+ msg.push("".into());
+ if old_assignment_opt.is_some() {
+ msg.push(format!(
+ "Optimal partition size: {} ({} in previous layout)",
+ ByteSize::b(partition_size).to_string_as(false),
+ ByteSize::b(self.partition_size).to_string_as(false)
+ ));
+ } else {
+ msg.push(format!(
+ "Optimal partition size: {}",
+ ByteSize::b(partition_size).to_string_as(false)
+ ));
+ }
+ // We write the partition size.
+ self.partition_size = partition_size;
+
+ if partition_size < 100 {
+ msg.push(
+ "WARNING: The partition size is low (< 100), make sure the capacities of your nodes are correct and are of at least a few MB"
+ .into(),
+ );
+ }
+
+ // We compute a first flow/assignment that is heuristically close to the previous
+ // assignment
+ let mut gflow =
+ self.compute_candidate_assignment(&zone_to_id, &old_assignment_opt, zone_redundancy)?;
+ if let Some(assoc) = &old_assignment_opt {
+ // We minimize the distance to the previous assignment.
+ self.minimize_rebalance_load(&mut gflow, &zone_to_id, assoc)?;
+ }
+
+ // We display statistics of the computation
+ msg.extend(self.output_stat(&gflow, &old_assignment_opt, &zone_to_id, &id_to_zone)?);
+
+ // We update the layout structure
+ self.update_ring_from_flow(id_to_zone.len(), &gflow)?;
+
+ if let Err(e) = self.check() {
+ return Err(Error::Message(
+ format!("Layout check returned an error: {}\nOriginal result of computation: <<<<\n{}\n>>>>", e, msg.join("\n"))
+ ));
+ }
+
+ Ok(msg)
+ }
+
+ /// The LwwMap of node roles might have changed. This function updates the node_id_vec
+ /// and returns the assignment given by ring, with the new indices of the nodes, and
+ /// None if the node is not present anymore.
+ /// We work with the assumption that only this function and calculate_new_assignment
+ /// do modify assignment_ring and node_id_vec.
+ fn update_node_id_vec(&mut self) -> Result<Option<Vec<Vec<usize>>>, Error> {
+ // (1) We compute the new node list
+ // Non gateway nodes should be coded on 8bits, hence they must be first in the list
+ // We build the new node ids
+ let new_non_gateway_nodes: Vec<Uuid> = self
+ .roles
+ .items()
+ .iter()
+ .filter(|(_, _, v)| matches!(&v.0, Some(r) if r.capacity.is_some()))
+ .map(|(k, _, _)| *k)
+ .collect();
+
+ if new_non_gateway_nodes.len() > MAX_NODE_NUMBER {
+ return Err(Error::Message(format!(
+ "There are more than {} non-gateway nodes in the new \
+ layout. This is not allowed.",
+ MAX_NODE_NUMBER
+ )));
+ }
+
+ let new_gateway_nodes: Vec<Uuid> = self
+ .roles
+ .items()
+ .iter()
+ .filter(|(_, _, v)| matches!(v, NodeRoleV(Some(r)) if r.capacity.is_none()))
+ .map(|(k, _, _)| *k)
+ .collect();
+
+ let old_node_id_vec = std::mem::take(&mut self.node_id_vec);
+
+ self.nongateway_node_count = new_non_gateway_nodes.len();
+ self.node_id_vec.clear();
+ self.node_id_vec.extend(new_non_gateway_nodes);
+ self.node_id_vec.extend(new_gateway_nodes);
+
+ let new_node_id_vec = &self.node_id_vec;
+
+ // (2) We retrieve the old association
+ // We rewrite the old association with the new indices. We only consider partition
+ // to node assignments where the node is still in use.
+ if self.ring_assignment_data.is_empty() {
+ // This is a new association
+ return Ok(None);
+ }
+
+ if self.ring_assignment_data.len() != NB_PARTITIONS * self.replication_factor {
+ return Err(Error::Message(
+ "The old assignment does not have a size corresponding to \
+ the old replication factor or the number of partitions."
+ .into(),
+ ));
+ }
+
+ // We build a translation table between the uuid and new ids
+ let mut uuid_to_new_id = HashMap::<Uuid, usize>::new();
+
+ // We add the indices of only the new non-gateway nodes that can be used in the
+ // association ring
+ for (i, uuid) in new_node_id_vec.iter().enumerate() {
+ uuid_to_new_id.insert(*uuid, i);
+ }
+
+ let mut old_assignment = vec![Vec::<usize>::new(); NB_PARTITIONS];
+ let rf = self.replication_factor;
+
+ for (p, old_assign_p) in old_assignment.iter_mut().enumerate() {
+ for old_id in &self.ring_assignment_data[p * rf..(p + 1) * rf] {
+ let uuid = old_node_id_vec[*old_id as usize];
+ if uuid_to_new_id.contains_key(&uuid) {
+ old_assign_p.push(uuid_to_new_id[&uuid]);
+ }
+ }
+ }
+
+ // We clear the ring assignemnt data
+ self.ring_assignment_data = Vec::<CompactNodeType>::new();
+
+ Ok(Some(old_assignment))
+ }
+
+ /// This function generates ids for the zone of the nodes appearing in
+ /// self.node_id_vec.
+ pub(crate) fn generate_nongateway_zone_ids(
+ &self,
+ ) -> Result<(Vec<String>, HashMap<String, usize>), Error> {
+ let mut id_to_zone = Vec::<String>::new();
+ let mut zone_to_id = HashMap::<String, usize>::new();
+
+ for uuid in self.nongateway_nodes().iter() {
+ let r = self.node_role(uuid).unwrap();
+ if !zone_to_id.contains_key(&r.zone) && r.capacity.is_some() {
+ zone_to_id.insert(r.zone.clone(), id_to_zone.len());
+ id_to_zone.push(r.zone.clone());
+ }
+ }
+ Ok((id_to_zone, zone_to_id))
+ }
+
+ /// This function computes by dichotomy the largest realizable partition size, given
+ /// the layout roles and parameters.
+ fn compute_optimal_partition_size(
+ &self,
+ zone_to_id: &HashMap<String, usize>,
+ zone_redundancy: usize,
+ ) -> Result<u64, Error> {
+ let empty_set = HashSet::<(usize, usize)>::new();
+ let mut g = self.generate_flow_graph(1, zone_to_id, &empty_set, zone_redundancy)?;
+ g.compute_maximal_flow()?;
+ if g.get_flow_value()? < (NB_PARTITIONS * self.replication_factor) as i64 {
+ return Err(Error::Message(
+ "The storage capacity of he cluster is to small. It is \
+ impossible to store partitions of size 1."
+ .into(),
+ ));
+ }
+
+ let mut s_down = 1;
+ let mut s_up = self.get_total_capacity();
+ while s_down + 1 < s_up {
+ g = self.generate_flow_graph(
+ (s_down + s_up) / 2,
+ zone_to_id,
+ &empty_set,
+ zone_redundancy,
+ )?;
+ g.compute_maximal_flow()?;
+ if g.get_flow_value()? < (NB_PARTITIONS * self.replication_factor) as i64 {
+ s_up = (s_down + s_up) / 2;
+ } else {
+ s_down = (s_down + s_up) / 2;
+ }
+ }
+
+ Ok(s_down)
+ }
+
+ fn generate_graph_vertices(nb_zones: usize, nb_nodes: usize) -> Vec<Vertex> {
+ let mut vertices = vec![Vertex::Source, Vertex::Sink];
+ for p in 0..NB_PARTITIONS {
+ vertices.push(Vertex::Pup(p));
+ vertices.push(Vertex::Pdown(p));
+ for z in 0..nb_zones {
+ vertices.push(Vertex::PZ(p, z));
+ }
+ }
+ for n in 0..nb_nodes {
+ vertices.push(Vertex::N(n));
+ }
+ vertices
+ }
+
+ /// Generates the graph to compute the maximal flow corresponding to the optimal
+ /// partition assignment.
+ /// exclude_assoc is the set of (partition, node) association that we are forbidden
+ /// to use (hence we do not add the corresponding edge to the graph). This parameter
+ /// is used to compute a first flow that uses only edges appearing in the previous
+ /// assignment. This produces a solution that heuristically should be close to the
+ /// previous one.
+ fn generate_flow_graph(
+ &self,
+ partition_size: u64,
+ zone_to_id: &HashMap<String, usize>,
+ exclude_assoc: &HashSet<(usize, usize)>,
+ zone_redundancy: usize,
+ ) -> Result<Graph<FlowEdge>, Error> {
+ let vertices =
+ LayoutVersion::generate_graph_vertices(zone_to_id.len(), self.nongateway_nodes().len());
+ let mut g = Graph::<FlowEdge>::new(&vertices);
+ let nb_zones = zone_to_id.len();
+ for p in 0..NB_PARTITIONS {
+ g.add_edge(Vertex::Source, Vertex::Pup(p), zone_redundancy as u64)?;
+ g.add_edge(
+ Vertex::Source,
+ Vertex::Pdown(p),
+ (self.replication_factor - zone_redundancy) as u64,
+ )?;
+ for z in 0..nb_zones {
+ g.add_edge(Vertex::Pup(p), Vertex::PZ(p, z), 1)?;
+ g.add_edge(
+ Vertex::Pdown(p),
+ Vertex::PZ(p, z),
+ self.replication_factor as u64,
+ )?;
+ }
+ }
+ for n in 0..self.nongateway_nodes().len() {
+ let node_capacity = self.expect_get_node_capacity(&self.node_id_vec[n]);
+ let node_zone = zone_to_id[self.expect_get_node_zone(&self.node_id_vec[n])];
+ g.add_edge(Vertex::N(n), Vertex::Sink, node_capacity / partition_size)?;
+ for p in 0..NB_PARTITIONS {
+ if !exclude_assoc.contains(&(p, n)) {
+ g.add_edge(Vertex::PZ(p, node_zone), Vertex::N(n), 1)?;
+ }
+ }
+ }
+ Ok(g)
+ }
+
+ /// This function computes a first optimal assignment (in the form of a flow graph).
+ fn compute_candidate_assignment(
+ &self,
+ zone_to_id: &HashMap<String, usize>,
+ prev_assign_opt: &Option<Vec<Vec<usize>>>,
+ zone_redundancy: usize,
+ ) -> Result<Graph<FlowEdge>, Error> {
+ // We list the (partition,node) associations that are not used in the
+ // previous assignment
+ let mut exclude_edge = HashSet::<(usize, usize)>::new();
+ if let Some(prev_assign) = prev_assign_opt {
+ let nb_nodes = self.nongateway_nodes().len();
+ for (p, prev_assign_p) in prev_assign.iter().enumerate() {
+ for n in 0..nb_nodes {
+ exclude_edge.insert((p, n));
+ }
+ for n in prev_assign_p.iter() {
+ exclude_edge.remove(&(p, *n));
+ }
+ }
+ }
+
+ // We compute the best flow using only the edges used in the previous assignment
+ let mut g = self.generate_flow_graph(
+ self.partition_size,
+ zone_to_id,
+ &exclude_edge,
+ zone_redundancy,
+ )?;
+ g.compute_maximal_flow()?;
+
+ // We add the excluded edges and compute the maximal flow with the full graph.
+ // The algorithm is such that it will start with the flow that we just computed
+ // and find ameliorating paths from that.
+ for (p, n) in exclude_edge.iter() {
+ let node_zone = zone_to_id[self.expect_get_node_zone(&self.node_id_vec[*n])];
+ g.add_edge(Vertex::PZ(*p, node_zone), Vertex::N(*n), 1)?;
+ }
+ g.compute_maximal_flow()?;
+ Ok(g)
+ }
+
+ /// This function updates the flow graph gflow to minimize the distance between
+ /// its corresponding assignment and the previous one
+ fn minimize_rebalance_load(
+ &self,
+ gflow: &mut Graph<FlowEdge>,
+ zone_to_id: &HashMap<String, usize>,
+ prev_assign: &[Vec<usize>],
+ ) -> Result<(), Error> {
+ // We define a cost function on the edges (pairs of vertices) corresponding
+ // to the distance between the two assignments.
+ let mut cost = CostFunction::new();
+ for (p, assoc_p) in prev_assign.iter().enumerate() {
+ for n in assoc_p.iter() {
+ let node_zone = zone_to_id[self.expect_get_node_zone(&self.node_id_vec[*n])];
+ cost.insert((Vertex::PZ(p, node_zone), Vertex::N(*n)), -1);
+ }
+ }
+
+ // We compute the maximal length of a simple path in gflow. It is used in the
+ // Bellman-Ford algorithm in optimize_flow_with_cost to set the number
+ // of iterations.
+ let nb_nodes = self.nongateway_nodes().len();
+ let path_length = 4 * nb_nodes;
+ gflow.optimize_flow_with_cost(&cost, path_length)?;
+
+ Ok(())
+ }
+
+ /// This function updates the assignment ring from the flow graph.
+ fn update_ring_from_flow(
+ &mut self,
+ nb_zones: usize,
+ gflow: &Graph<FlowEdge>,
+ ) -> Result<(), Error> {
+ self.ring_assignment_data = Vec::<CompactNodeType>::new();
+ for p in 0..NB_PARTITIONS {
+ for z in 0..nb_zones {
+ let assoc_vertex = gflow.get_positive_flow_from(Vertex::PZ(p, z))?;
+ for vertex in assoc_vertex.iter() {
+ if let Vertex::N(n) = vertex {
+ self.ring_assignment_data.push((*n).try_into().unwrap());
+ }
+ }
+ }
+ }
+
+ if self.ring_assignment_data.len() != NB_PARTITIONS * self.replication_factor {
+ return Err(Error::Message(
+ "Critical Error : the association ring we produced does not \
+ have the right size."
+ .into(),
+ ));
+ }
+ Ok(())
+ }
+
+ /// This function returns a message summing up the partition repartition of the new
+ /// layout, and other statistics of the partition assignment computation.
+ fn output_stat(
+ &self,
+ gflow: &Graph<FlowEdge>,
+ prev_assign_opt: &Option<Vec<Vec<usize>>>,
+ zone_to_id: &HashMap<String, usize>,
+ id_to_zone: &[String],
+ ) -> Result<Message, Error> {
+ let mut msg = Message::new();
+
+ let used_cap = self.partition_size * NB_PARTITIONS as u64 * self.replication_factor as u64;
+ let total_cap = self.get_total_capacity();
+ let percent_cap = 100.0 * (used_cap as f32) / (total_cap as f32);
+ msg.push(format!(
+ "Usable capacity / total cluster capacity: {} / {} ({:.1} %)",
+ ByteSize::b(used_cap).to_string_as(false),
+ ByteSize::b(total_cap).to_string_as(false),
+ percent_cap
+ ));
+ msg.push(format!(
+ "Effective capacity (replication factor {}): {}",
+ self.replication_factor,
+ ByteSize::b(used_cap / self.replication_factor as u64).to_string_as(false)
+ ));
+ if percent_cap < 80. {
+ msg.push("".into());
+ msg.push(
+ "If the percentage is too low, it might be that the \
+ cluster topology and redundancy constraints are forcing the use of nodes/zones with small \
+ storage capacities."
+ .into(),
+ );
+ msg.push(
+ "You might want to move storage capacity between zones or relax the redundancy constraint."
+ .into(),
+ );
+ msg.push(
+ "See the detailed statistics below and look for saturated nodes/zones.".into(),
+ );
+ }
+
+ // We define and fill in the following tables
+ let storing_nodes = self.nongateway_nodes();
+ let mut new_partitions = vec![0; storing_nodes.len()];
+ let mut stored_partitions = vec![0; storing_nodes.len()];
+
+ let mut new_partitions_zone = vec![0; id_to_zone.len()];
+ let mut stored_partitions_zone = vec![0; id_to_zone.len()];
+
+ for p in 0..NB_PARTITIONS {
+ for z in 0..id_to_zone.len() {
+ let pz_nodes = gflow.get_positive_flow_from(Vertex::PZ(p, z))?;
+ if !pz_nodes.is_empty() {
+ stored_partitions_zone[z] += 1;
+ if let Some(prev_assign) = prev_assign_opt {
+ let mut old_zones_of_p = Vec::<usize>::new();
+ for n in prev_assign[p].iter() {
+ old_zones_of_p
+ .push(zone_to_id[self.expect_get_node_zone(&self.node_id_vec[*n])]);
+ }
+ if !old_zones_of_p.contains(&z) {
+ new_partitions_zone[z] += 1;
+ }
+ }
+ }
+ for vert in pz_nodes.iter() {
+ if let Vertex::N(n) = *vert {
+ stored_partitions[n] += 1;
+ if let Some(prev_assign) = prev_assign_opt {
+ if !prev_assign[p].contains(&n) {
+ new_partitions[n] += 1;
+ }
+ }
+ }
+ }
+ }
+ }
+
+ if prev_assign_opt.is_none() {
+ new_partitions = stored_partitions.clone();
+ //new_partitions_zone = stored_partitions_zone.clone();
+ }
+
+ // We display the statistics
+
+ msg.push("".into());
+ if prev_assign_opt.is_some() {
+ let total_new_partitions: usize = new_partitions.iter().sum();
+ msg.push(format!(
+ "A total of {} new copies of partitions need to be \
+ transferred.",
+ total_new_partitions
+ ));
+ msg.push("".into());
+ }
+
+ let mut table = vec![];
+ for z in 0..id_to_zone.len() {
+ let mut nodes_of_z = Vec::<usize>::new();
+ for n in 0..storing_nodes.len() {
+ if self.expect_get_node_zone(&self.node_id_vec[n]) == id_to_zone[z] {
+ nodes_of_z.push(n);
+ }
+ }
+ let replicated_partitions: usize =
+ nodes_of_z.iter().map(|n| stored_partitions[*n]).sum();
+ table.push(format!(
+ "{}\tTags\tPartitions\tCapacity\tUsable capacity",
+ id_to_zone[z]
+ ));
+
+ let available_cap_z: u64 = self.partition_size * replicated_partitions as u64;
+ let mut total_cap_z = 0;
+ for n in nodes_of_z.iter() {
+ total_cap_z += self.expect_get_node_capacity(&self.node_id_vec[*n]);
+ }
+ let percent_cap_z = 100.0 * (available_cap_z as f32) / (total_cap_z as f32);
+
+ for n in nodes_of_z.iter() {
+ let available_cap_n = stored_partitions[*n] as u64 * self.partition_size;
+ let total_cap_n = self.expect_get_node_capacity(&self.node_id_vec[*n]);
+ let tags_n = (self.node_role(&self.node_id_vec[*n]).ok_or("<??>"))?.tags_string();
+ table.push(format!(
+ " {:?}\t{}\t{} ({} new)\t{}\t{} ({:.1}%)",
+ self.node_id_vec[*n],
+ tags_n,
+ stored_partitions[*n],
+ new_partitions[*n],
+ ByteSize::b(total_cap_n).to_string_as(false),
+ ByteSize::b(available_cap_n).to_string_as(false),
+ (available_cap_n as f32) / (total_cap_n as f32) * 100.0,
+ ));
+ }
+
+ table.push(format!(
+ " TOTAL\t\t{} ({} unique)\t{}\t{} ({:.1}%)",
+ replicated_partitions,
+ stored_partitions_zone[z],
+ //new_partitions_zone[z],
+ ByteSize::b(total_cap_z).to_string_as(false),
+ ByteSize::b(available_cap_z).to_string_as(false),
+ percent_cap_z
+ ));
+ table.push("".into());
+ }
+ msg.push(format_table::format_table_to_string(table));
+
+ Ok(msg)
+ }
+}