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-rw-r--r--src/rpc/graph_algo.rs440
-rw-r--r--src/rpc/layout.rs795
-rw-r--r--src/rpc/lib.rs2
-rw-r--r--src/rpc/ring.rs1
-rw-r--r--src/rpc/system.rs5
-rw-r--r--src/util/bipartite.rs363
-rw-r--r--src/util/lib.rs1
7 files changed, 918 insertions, 689 deletions
diff --git a/src/rpc/graph_algo.rs b/src/rpc/graph_algo.rs
new file mode 100644
index 00000000..1a809b80
--- /dev/null
+++ b/src/rpc/graph_algo.rs
@@ -0,0 +1,440 @@
+
+//! This module deals with graph algorithms.
+//! It is used in layout.rs to build the partition to node assignation.
+
+use rand::prelude::SliceRandom;
+use std::cmp::{max, min};
+use std::collections::VecDeque;
+use std::collections::HashMap;
+
+//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.
+//The graph is stored as an adjacency list
+#[derive(Clone, Copy, Debug)]
+pub struct FlowEdge {
+ cap: u32, //flow maximal capacity of the edge
+ flow: i32, //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.
+//The graph is stored as a list of edges (u,v).
+#[derive(Clone, Copy, Debug)]
+pub struct WeightedEdge {
+ w: i32, //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 usize indices
+//and Vec instead of HashMap in the graph algorithm to optimize execution speed.
+pub struct Graph<E : Edge>{
+ vertextoid : HashMap<Vertex , usize>,
+ idtovertex : Vec<Vertex>,
+
+ graph : Vec< Vec<E> >
+}
+
+pub type CostFunction = HashMap<(Vertex,Vertex), i32>;
+
+impl<E : Edge> Graph<E>{
+ pub fn new(vertices : &[Vertex]) -> Self {
+ let mut map = HashMap::<Vertex, usize>::new();
+ for i in 0..vertices.len() {
+ map.insert(vertices[i] , i);
+ }
+ return Graph::<E> {
+ vertextoid : map,
+ idtovertex: vertices.to_vec(),
+ graph : vec![Vec::< E >::new(); vertices.len() ]
+ }
+ }
+}
+
+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: u32) -> Result<(), String>{
+ if !self.vertextoid.contains_key(&u) || !self.vertextoid.contains_key(&v) {
+ return Err("The graph does not contain the provided vertex.".to_string());
+ }
+ let idu = self.vertextoid[&u];
+ let idv = self.vertextoid[&v];
+ 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>{
+ if !self.vertextoid.contains_key(&v) {
+ return Err("The graph does not contain the provided vertex.".to_string());
+ }
+ let idv = self.vertextoid[&v];
+ let mut result = Vec::<Vertex>::new();
+ for edge in self.graph[idv].iter() {
+ if edge.flow > 0 {
+ result.push(self.idtovertex[edge.dest]);
+ }
+ }
+ return Ok(result);
+ }
+
+
+ //This function returns the value of the flow incoming to v.
+ pub fn get_inflow(&self , v:Vertex) -> Result< i32 , String>{
+ if !self.vertextoid.contains_key(&v) {
+ return Err("The graph does not contain the provided vertex.".to_string());
+ }
+ let idv = self.vertextoid[&v];
+ let mut result = 0;
+ for edge in self.graph[idv].iter() {
+ result += max(0,self.graph[edge.dest][edge.rev].flow);
+ }
+ return Ok(result);
+ }
+
+ //This function returns the value of the flow outgoing from v.
+ pub fn get_outflow(&self , v:Vertex) -> Result< i32 , String>{
+ if !self.vertextoid.contains_key(&v) {
+ return Err("The graph does not contain the provided vertex.".to_string());
+ }
+ let idv = self.vertextoid[&v];
+ let mut result = 0;
+ for edge in self.graph[idv].iter() {
+ result += max(0,edge.flow);
+ }
+ return 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<i32, String> {
+ return 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) {
+ let mut rng = rand::thread_rng();
+ 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 n the graph
+ pub fn flow_upper_bound(&self) -> u32{
+ let idsource = self.vertextoid[&Vertex::Source];
+ let mut flow_upper_bound = 0;
+ for edge in self.graph[idsource].iter(){
+ flow_upper_bound += edge.cap;
+ }
+ return 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> {
+ if !self.vertextoid.contains_key(&Vertex::Source) {
+ return Err("The graph does not contain a source.".to_string());
+ }
+ if !self.vertextoid.contains_key(&Vertex::Sink) {
+ return Err("The graph does not contain a sink.".to_string());
+ }
+
+ let idsource = self.vertextoid[&Vertex::Source];
+ let idsink = self.vertextoid[&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
+ //assignation, 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 !fifo.is_empty() {
+ if let Some((id, lvl)) = fifo.pop_front() {
+ if level[id] == None { //it means id has not yet been reached
+ level[id] = Some(lvl);
+ for edge in self.graph[id].iter() {
+ if edge.cap as i32 - edge.flow > 0 {
+ fifo.push_back((edge.dest, lvl + 1));
+ }
+ }
+ }
+ }
+ }
+ if level[idsink] == 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 = VecDeque::new();
+
+ lifo.push_back((idsource, flow_upper_bound));
+
+ while let Some((id_tmp, f_tmp)) = lifo.back() {
+ let id = *id_tmp;
+ let f = *f_tmp;
+ if id == idsink {
+ //The DFS reached the sink, we can add a
+ //residual flow.
+ lifo.pop_back();
+ while !lifo.is_empty() {
+ if let Some((id, _)) = lifo.pop_back() {
+ let nbd = next_nbd[id];
+ self.graph[id][nbd].flow += f as i32;
+ 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 i32;
+ }
+ }
+ lifo.push_back((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_back();
+ if let Some((parent, _)) = lifo.back() {
+ next_nbd[*parent] += 1;
+ }
+ continue;
+ }
+ //else we can try to send flow from id to its nbd
+ let new_flow = min(f, self.graph[id][nbd].cap - self.graph[id][nbd].flow as u32 );
+ if let (Some(lvldest), Some(lvlid)) =
+ (level[self.graph[id][nbd].dest], level[id]){
+ if lvldest <= lvlid || new_flow == 0 {
+ //We cannot send flow to nbd.
+ next_nbd[id] += 1;
+ continue;
+ }
+ }
+ //otherwise, we send flow to nbd.
+ lifo.push_back((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.len() > 0 {
+ //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.vertextoid[&c[i]];
+ let idv = self.vertextoid[&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);
+ }
+ return 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.idtovertex);
+ let nb_vertices = self.idtovertex.len();
+ for i in 0..nb_vertices {
+ for edge in self.graph[i].iter() {
+ if edge.cap as i32 -edge.flow > 0 {
+ //It is possible to send overflow through this edge
+ let u = self.idtovertex[i];
+ let v = self.idtovertex[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)?;
+ }
+ }
+ }
+ }
+ return 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: i32) -> Result<(), String>{
+ if !self.vertextoid.contains_key(&u) || !self.vertextoid.contains_key(&v) {
+ return Err("The graph does not contain the provided vertex.".to_string());
+ }
+ let idu = self.vertextoid[&u];
+ let idv = self.vertextoid[&v];
+ self.graph[idu].push( WeightedEdge{w: 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 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.idtovertex[*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] == None {
+ time_of_discovery[id] = Some(t);
+ if let Some(i) = forest[id] {
+ id = i;
+ }
+ else{
+ break;
+ }
+ }
+ if forest[id] != None && 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 id2 = id;
+ while let Some(id2) = forest[id2] {
+ if id2 != id {
+ cy.push(id2);
+ }
+ else {
+ break;
+ }
+ }
+ cycles.push(cy);
+ }
+ }
+ return cycles;
+}
+
+
+//====================================================================================
+//====================================================================================
+//====================================================================================
+//====================================================================================
+//====================================================================================
+//====================================================================================
+
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn test_flow() {
+ let left_vec = vec![3; 8];
+ let right_vec = vec![0, 4, 8, 4, 8];
+ //There are asserts in the function that computes the flow
+ }
+
+ //maybe add tests relative to the matching optilization ?
+}
diff --git a/src/rpc/layout.rs b/src/rpc/layout.rs
index 40f97368..ff60ce98 100644
--- a/src/rpc/layout.rs
+++ b/src/rpc/layout.rs
@@ -1,17 +1,23 @@
-use std::cmp::min;
use std::cmp::Ordering;
use std::collections::HashMap;
+use std::collections::HashSet;
+
+use hex::ToHex;
use serde::{Deserialize, Serialize};
-use garage_util::bipartite::*;
use garage_util::crdt::{AutoCrdt, Crdt, LwwMap};
use garage_util::data::*;
-use rand::prelude::SliceRandom;
+use crate::graph_algo::*;
use crate::ring::*;
+use std::convert::TryInto;
+
+//The Message type will be used to collect information on the algorithm.
+type Message = Vec<String>;
+
/// The layout of the cluster, i.e. the list of roles
/// which are assigned to each cluster node
#[derive(Clone, Debug, Serialize, Deserialize)]
@@ -19,12 +25,21 @@ pub struct ClusterLayout {
pub version: u64,
pub replication_factor: usize,
+ #[serde(default="default_one")]
+ pub zone_redundancy: 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.
+ #[serde(default="default_zero")]
+ pub partition_size: u32,
+
pub roles: LwwMap<Uuid, NodeRoleV>,
/// 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
+ /// 1. non-gateway nodes are first so that they have lower numbers holding
+ /// in u8 (the number of non-gateway nodes is at most 256).
/// 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>,
@@ -38,6 +53,15 @@ pub struct ClusterLayout {
pub staging_hash: Hash,
}
+fn default_one() -> usize{
+ return 1;
+}
+fn default_zero() -> u32{
+ return 0;
+}
+
+const NB_PARTITIONS : usize = 1usize << PARTITION_BITS;
+
#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Debug, Serialize, Deserialize)]
pub struct NodeRoleV(pub Option<NodeRole>);
@@ -66,16 +90,31 @@ impl NodeRole {
None => "gateway".to_string(),
}
}
+
+ pub fn tags_string(&self) -> String {
+ let mut tags = String::new();
+ if self.tags.len() == 0 {
+ return tags
+ }
+ tags.push_str(&self.tags[0].clone());
+ for t in 1..self.tags.len(){
+ tags.push_str(",");
+ tags.push_str(&self.tags[t].clone());
+ }
+ return tags;
+ }
}
impl ClusterLayout {
- pub fn new(replication_factor: usize) -> Self {
+ pub fn new(replication_factor: usize, zone_redundancy: usize) -> Self {
let empty_lwwmap = LwwMap::new();
let empty_lwwmap_hash = blake2sum(&rmp_to_vec_all_named(&empty_lwwmap).unwrap()[..]);
ClusterLayout {
version: 0,
replication_factor,
+ zone_redundancy,
+ partition_size: 0,
roles: LwwMap::new(),
node_id_vec: Vec::new(),
ring_assignation_data: Vec::new(),
@@ -122,6 +161,44 @@ impl ClusterLayout {
}
}
+ ///Returns the uuids of the non_gateway nodes in self.node_id_vec.
+ pub fn useful_nodes(&self) -> Vec<Uuid> {
+ let mut result = Vec::<Uuid>::new();
+ for uuid in self.node_id_vec.iter() {
+ match self.node_role(uuid) {
+ Some(role) if role.capacity != None => result.push(*uuid),
+ _ => ()
+ }
+ }
+ return result;
+ }
+
+ ///Given a node uuids, this function returns the label of its zone
+ pub fn get_node_zone(&self, uuid : &Uuid) -> Result<String,String> {
+ match self.node_role(uuid) {
+ Some(role) => return Ok(role.zone.clone()),
+ _ => return Err("The Uuid does not correspond to a node present in the cluster.".to_string())
+ }
+ }
+
+ ///Given a node uuids, this function returns its capacity or fails if it does not have any
+ pub fn get_node_capacity(&self, uuid : &Uuid) -> Result<u32,String> {
+ match self.node_role(uuid) {
+ Some(NodeRole{capacity : Some(cap), zone: _, tags: _}) => return Ok(*cap),
+ _ => return Err("The Uuid does not correspond to a node present in the cluster or this node does not have a positive capacity.".to_string())
+ }
+ }
+
+ ///Returns the sum of capacities of non gateway nodes in the cluster
+ pub fn get_total_capacity(&self) -> Result<u32,String> {
+ let mut total_capacity = 0;
+ for uuid in self.useful_nodes().iter() {
+ total_capacity += self.get_node_capacity(uuid)?;
+ }
+ return Ok(total_capacity);
+ }
+
+
/// Check a cluster layout for internal consistency
/// returns true if consistent, false if error
pub fn check(&self) -> bool {
@@ -168,342 +245,412 @@ impl ClusterLayout {
true
}
+}
+
+impl ClusterLayout {
/// This function calculates a new partition-to-node assignation.
- /// The computed assignation maximizes the capacity of a
+ /// The computed assignation 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 assignation, it minimizes the distance to
/// the former assignation (if any) to minimize the amount of
- /// data to be moved. A heuristic ensures node triplets
- /// dispersion (in garage_util::bipartite::optimize_matching()).
- pub fn calculate_partition_assignation(&mut self) -> bool {
+ /// data to be moved.
+ pub fn calculate_partition_assignation(&mut self, replication:usize, redundancy:usize) -> Result<Message,String> {
//The nodes might have been updated, some might have been deleted.
//So we need to first update the list of nodes and retrieve the
//assignation.
- let old_node_assignation = self.update_nodes_and_ring();
-
- let (node_zone, _) = self.get_node_zone_capacity();
-
- //We compute the optimal number of partition to assign to
- //every node and zone.
- if let Some((part_per_nod, part_per_zone)) = self.optimal_proportions() {
- //We collect part_per_zone in a vec to not rely on the
- //arbitrary order in which elements are iterated in
- //Hashmap::iter()
- let part_per_zone_vec = part_per_zone
- .iter()
- .map(|(x, y)| (x.clone(), *y))
- .collect::<Vec<(String, usize)>>();
- //We create an indexing of the zones
- let mut zone_id = HashMap::<String, usize>::new();
- for (i, ppz) in part_per_zone_vec.iter().enumerate() {
- zone_id.insert(ppz.0.clone(), i);
- }
-
- //We compute a candidate for the new partition to zone
- //assignation.
- let nb_zones = part_per_zone.len();
- let nb_nodes = part_per_nod.len();
- let nb_partitions = 1 << PARTITION_BITS;
- let left_cap_vec = vec![self.replication_factor as u32; nb_partitions];
- let right_cap_vec = part_per_zone_vec.iter().map(|(_, y)| *y as u32).collect();
- let mut zone_assignation = dinic_compute_matching(left_cap_vec, right_cap_vec);
-
- //We create the structure for the partition-to-node assignation.
- let mut node_assignation = vec![vec![None; self.replication_factor]; nb_partitions];
- //We will decrement part_per_nod to keep track of the number
- //of partitions that we still have to associate.
- let mut part_per_nod = part_per_nod;
-
- //We minimize the distance to the former assignation(if any)
-
- //We get the id of the zones of the former assignation
- //(and the id no_zone if there is no node assignated)
- let no_zone = part_per_zone_vec.len();
- let old_zone_assignation: Vec<Vec<usize>> = old_node_assignation
- .iter()
- .map(|x| {
- x.iter()
- .map(|id| match *id {
- Some(i) => zone_id[&node_zone[i]],
- None => no_zone,
- })
- .collect()
- })
- .collect();
-
- //We minimize the distance to the former zone assignation
- zone_assignation =
- optimize_matching(&old_zone_assignation, &zone_assignation, nb_zones + 1); //+1 for no_zone
-
- //We need to assign partitions to nodes in their zone
- //We first put the nodes assignation that can stay the same
- for i in 0..nb_partitions {
- for j in 0..self.replication_factor {
- if let Some(Some(former_node)) = old_node_assignation[i].iter().find(|x| {
- if let Some(id) = x {
- zone_id[&node_zone[*id]] == zone_assignation[i][j]
- } else {
- false
- }
- }) {
- if part_per_nod[*former_node] > 0 {
- node_assignation[i][j] = Some(*former_node);
- part_per_nod[*former_node] -= 1;
- }
- }
- }
- }
-
- //We complete the assignation of partitions to nodes
- let mut rng = rand::thread_rng();
- for i in 0..nb_partitions {
- for j in 0..self.replication_factor {
- if node_assignation[i][j] == None {
- let possible_nodes: Vec<usize> = (0..nb_nodes)
- .filter(|id| {
- zone_id[&node_zone[*id]] == zone_assignation[i][j]
- && part_per_nod[*id] > 0
- })
- .collect();
- assert!(!possible_nodes.is_empty());
- //We randomly pick a node
- if let Some(nod) = possible_nodes.choose(&mut rng) {
- node_assignation[i][j] = Some(*nod);
- part_per_nod[*nod] -= 1;
- }
- }
- }
- }
-
- //We write the assignation in the 1D table
- self.ring_assignation_data = Vec::<CompactNodeType>::new();
- for ass in node_assignation {
- for nod in ass {
- if let Some(id) = nod {
- self.ring_assignation_data.push(id as CompactNodeType);
- } else {
- panic!()
- }
- }
- }
-
- true
- } else {
- false
- }
- }
+
+ //We update the node ids, since the node list might have changed with the staged
+ //changes in the layout. We retrieve the old_assignation reframed with the new ids
+ let old_assignation_opt = self.update_node_id_vec()?;
+ self.replication_factor = replication;
+ self.zone_redundancy = redundancy;
+
+ let mut msg = Message::new();
+ msg.push(format!("Computation of a new cluster layout where partitions are
+ replicated {} times on at least {} distinct zones.", replication, redundancy));
+
+ //We generate for once numerical ids for the zone, to use them as indices in the
+ //flow graphs.
+ let (id_to_zone , zone_to_id) = self.generate_zone_ids()?;
+
+ msg.push(format!("The cluster contains {} nodes spread over {} zones.",
+ self.useful_nodes().len(), id_to_zone.len()));
+
+ //We compute the optimal partition size
+ let partition_size = self.compute_optimal_partition_size(&zone_to_id)?;
+ if old_assignation_opt != None {
+ msg.push(format!("Given the replication and redundancy constraint, the
+ optimal size of a partition is {}. In the previous layout, it used to
+ be {}.", partition_size, self.partition_size));
+ }
+ else {
+ msg.push(format!("Given the replication and redundancy constraints, the
+ optimal size of a partition is {}.", partition_size));
+ }
+ self.partition_size = partition_size;
+
+ //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_assignation_opt)?;
+
+ if let Some(assoc) = &old_assignation_opt {
+ //We minimize the distance to the previous assignment.
+ self.minimize_rebalance_load(&mut gflow, &zone_to_id, &assoc)?;
+ }
+
+ msg.append(&mut self.output_stat(&gflow, &old_assignation_opt, &zone_to_id,&id_to_zone)?);
+
+ //We update the layout structure
+ self.update_ring_from_flow(id_to_zone.len() , &gflow)?;
+ return Ok(msg);
+ }
/// The LwwMap of node roles might have changed. This function updates the node_id_vec
/// and returns the assignation given by ring, with the new indices of the nodes, and
- /// None of the node is not present anymore.
+ /// None if the node is not present anymore.
/// We work with the assumption that only this function and calculate_new_assignation
/// do modify assignation_ring and node_id_vec.
- fn update_nodes_and_ring(&mut self) -> Vec<Vec<Option<usize>>> {
- let nb_partitions = 1usize << PARTITION_BITS;
- let mut node_assignation = vec![vec![None; self.replication_factor]; nb_partitions];
- let rf = self.replication_factor;
- let ring = &self.ring_assignation_data;
-
- let new_node_id_vec: Vec<Uuid> = self.roles.items().iter().map(|(k, _, _)| *k).collect();
-
- if ring.len() == rf * nb_partitions {
- for i in 0..nb_partitions {
- for j in 0..self.replication_factor {
- node_assignation[i][j] = new_node_id_vec
- .iter()
- .position(|id| *id == self.node_id_vec[ring[i * rf + j] as usize]);
- }
- }
- }
-
- self.node_id_vec = new_node_id_vec;
- self.ring_assignation_data = vec![];
- node_assignation
+ fn update_node_id_vec(&mut self) -> Result< Option< Vec<Vec<usize> > > ,String> {
+ // (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 mut new_non_gateway_nodes: Vec<Uuid> = self.roles.items().iter()
+ .filter(|(_, _, v)|
+ match &v.0 {Some(r) if r.capacity != None => true, _=> false })
+ .map(|(k, _, _)| *k).collect();
+
+ if new_non_gateway_nodes.len() > MAX_NODE_NUMBER {
+ return Err(format!("There are more than {} non-gateway nodes in the new layout. This is not allowed.", MAX_NODE_NUMBER).to_string());
+ }
+
+ let mut new_gateway_nodes: Vec<Uuid> = self.roles.items().iter()
+ .filter(|(_, _, v)|
+ match v {NodeRoleV(Some(r)) if r.capacity == None => true, _=> false })
+ .map(|(k, _, _)| *k).collect();
+
+ let nb_useful_nodes = new_non_gateway_nodes.len();
+ let mut new_node_id_vec = Vec::<Uuid>::new();
+ new_node_id_vec.append(&mut new_non_gateway_nodes);
+ new_node_id_vec.append(&mut new_gateway_nodes);
+
+
+ // (2) We retrieve the old association
+ //We rewrite the old association with the new indices. We only consider partition
+ //to node assignations where the node is still in use.
+ let nb_partitions = 1usize << PARTITION_BITS;
+ let mut old_assignation = vec![ Vec::<usize>::new() ; nb_partitions];
+
+ if self.ring_assignation_data.len() == 0 {
+ //This is a new association
+ return Ok(None);
+ }
+ if self.ring_assignation_data.len() != nb_partitions * self.replication_factor {
+ return Err("The old assignation does not have a size corresponding to the old replication factor or the number of partitions.".to_string());
+ }
+
+ //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 in 0..nb_useful_nodes {
+ uuid_to_new_id.insert(new_node_id_vec[i], i );
+ }
+
+ let rf= self.replication_factor;
+ for p in 0..nb_partitions {
+ for old_id in &self.ring_assignation_data[p*rf..(p+1)*rf] {
+ let uuid = self.node_id_vec[*old_id as usize];
+ if uuid_to_new_id.contains_key(&uuid) {
+ old_assignation[p].push(uuid_to_new_id[&uuid]);
+ }
+ }
+ }
+
+ //We write the results
+ self.node_id_vec = new_node_id_vec;
+ self.ring_assignation_data = Vec::<CompactNodeType>::new();
+
+ return Ok(Some(old_assignation));
}
- ///This function compute the number of partition to assign to
- ///every node and zone, so that every partition is replicated
- ///self.replication_factor times and the capacity of a partition
- ///is maximized.
- fn optimal_proportions(&mut self) -> Option<(Vec<usize>, HashMap<String, usize>)> {
- let mut zone_capacity: HashMap<String, u32> = HashMap::new();
-
- let (node_zone, node_capacity) = self.get_node_zone_capacity();
- let nb_nodes = self.node_id_vec.len();
-
- for i in 0..nb_nodes {
- if zone_capacity.contains_key(&node_zone[i]) {
- zone_capacity.insert(
- node_zone[i].clone(),
- zone_capacity[&node_zone[i]] + node_capacity[i],
- );
- } else {
- zone_capacity.insert(node_zone[i].clone(), node_capacity[i]);
- }
- }
-
- //Compute the optimal number of partitions per zone
- let sum_capacities: u32 = zone_capacity.values().sum();
-
- if sum_capacities == 0 {
- println!("No storage capacity in the network.");
- return None;
- }
-
- let nb_partitions = 1 << PARTITION_BITS;
- //Initially we would like to use zones porportionally to
- //their capacity.
- //However, a large zone can be associated to at most
- //nb_partitions to ensure replication of the date.
- //So we take the min with nb_partitions:
- let mut part_per_zone: HashMap<String, usize> = zone_capacity
- .iter()
- .map(|(k, v)| {
- (
- k.clone(),
- min(
- nb_partitions,
- (self.replication_factor * nb_partitions * *v as usize)
- / sum_capacities as usize,
- ),
- )
- })
- .collect();
-
- //The replication_factor-1 upper bounds the number of
- //part_per_zones that are greater than nb_partitions
- for _ in 1..self.replication_factor {
- //The number of partitions that are not assignated to
- //a zone that takes nb_partitions.
- let sum_capleft: u32 = zone_capacity
- .keys()
- .filter(|k| part_per_zone[*k] < nb_partitions)
- .map(|k| zone_capacity[k])
- .sum();
-
- //The number of replication of the data that we need
- //to ensure.
- let repl_left = self.replication_factor
- - part_per_zone
- .values()
- .filter(|x| **x == nb_partitions)
- .count();
- if repl_left == 0 {
- break;
- }
-
- for k in zone_capacity.keys() {
- if part_per_zone[k] != nb_partitions {
- part_per_zone.insert(
- k.to_string(),
- min(
- nb_partitions,
- (nb_partitions * zone_capacity[k] as usize * repl_left)
- / sum_capleft as usize,
- ),
- );
- }
- }
- }
-
- //Now we divide the zone's partition share proportionally
- //between their nodes.
-
- let mut part_per_nod: Vec<usize> = (0..nb_nodes)
- .map(|i| {
- (part_per_zone[&node_zone[i]] * node_capacity[i] as usize)
- / zone_capacity[&node_zone[i]] as usize
- })
- .collect();
-
- //We must update the part_per_zone to make it correspond to
- //part_per_nod (because of integer rounding)
- part_per_zone = part_per_zone.iter().map(|(k, _)| (k.clone(), 0)).collect();
- for i in 0..nb_nodes {
- part_per_zone.insert(
- node_zone[i].clone(),
- part_per_zone[&node_zone[i]] + part_per_nod[i],
- );
- }
-
- //Because of integer rounding, the total sum of part_per_nod
- //might not be replication_factor*nb_partitions.
- // We need at most to add 1 to every non maximal value of
- // part_per_nod. The capacity of a partition will be bounded
- // by the minimal value of
- // node_capacity_vec[i]/part_per_nod[i]
- // so we try to maximize this minimal value, keeping the
- // part_per_zone capped
-
- let discrepancy: usize =
- nb_partitions * self.replication_factor - part_per_nod.iter().sum::<usize>();
-
- //We use a stupid O(N^2) algorithm. If the number of nodes
- //is actually expected to be high, one should optimize this.
-
- for _ in 0..discrepancy {
- if let Some(idmax) = (0..nb_nodes)
- .filter(|i| part_per_zone[&node_zone[*i]] < nb_partitions)
- .max_by(|i, j| {
- (node_capacity[*i] * (part_per_nod[*j] + 1) as u32)
- .cmp(&(node_capacity[*j] * (part_per_nod[*i] + 1) as u32))
- }) {
- part_per_nod[idmax] += 1;
- part_per_zone.insert(
- node_zone[idmax].clone(),
- part_per_zone[&node_zone[idmax]] + 1,
- );
- }
- }
-
- //We check the algorithm consistency
-
- let discrepancy: usize =
- nb_partitions * self.replication_factor - part_per_nod.iter().sum::<usize>();
- assert!(discrepancy == 0);
- assert!(if let Some(v) = part_per_zone.values().max() {
- *v <= nb_partitions
- } else {
- false
- });
-
- Some((part_per_nod, part_per_zone))
- }
-
- //Returns vectors of zone and capacity; indexed by the same (temporary)
- //indices as node_id_vec.
- fn get_node_zone_capacity(&self) -> (Vec<String>, Vec<u32>) {
- let node_zone = self
- .node_id_vec
- .iter()
- .map(|id_nod| match self.node_role(id_nod) {
- Some(NodeRole {
- zone,
- capacity: _,
- tags: _,
- }) => zone.clone(),
- _ => "".to_string(),
- })
- .collect();
-
- let node_capacity = self
- .node_id_vec
- .iter()
- .map(|id_nod| match self.node_role(id_nod) {
- Some(NodeRole {
- zone: _,
- capacity: Some(c),
- tags: _,
- }) => *c,
- _ => 0,
- })
- .collect();
-
- (node_zone, node_capacity)
- }
+ ///This function generates ids for the zone of the nodes appearing in
+ ///self.node_id_vec.
+ fn generate_zone_ids(&self) -> Result<(Vec<String>, HashMap<String, usize>),String>{
+ let mut id_to_zone = Vec::<String>::new();
+ let mut zone_to_id = HashMap::<String,usize>::new();
+
+ for uuid in self.node_id_vec.iter() {
+ if self.roles.get(uuid) == None {
+ return Err("The uuid was not found in the node roles (this should not happen, it might be a critical error).".to_string());
+ }
+ match self.node_role(&uuid) {
+ Some(r) => if !zone_to_id.contains_key(&r.zone) && r.capacity != None {
+ zone_to_id.insert(r.zone.clone() , id_to_zone.len());
+ id_to_zone.push(r.zone.clone());
+ }
+ _ => ()
+ }
+ }
+ return Ok((id_to_zone, zone_to_id));
+ }
+
+ ///This function computes by dichotomy the largest realizable partition size, given
+ ///the layout.
+ fn compute_optimal_partition_size(&self, zone_to_id: &HashMap<String, usize>) -> Result<u32,String>{
+ let nb_partitions = 1usize << PARTITION_BITS;
+ let empty_set = HashSet::<(usize,usize)>::new();
+ let mut g = self.generate_flow_graph(1, zone_to_id, &empty_set)?;
+ g.compute_maximal_flow()?;
+ if g.get_flow_value()? < (nb_partitions*self.replication_factor).try_into().unwrap() {
+ return Err("The storage capacity of he cluster is to small. It is impossible to store partitions of size 1.".to_string());
+ }
+
+ 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)?;
+ g.compute_maximal_flow()?;
+ if g.get_flow_value()? < (nb_partitions*self.replication_factor).try_into().unwrap() {
+ s_up = (s_down+s_up)/2;
+ }
+ else {
+ s_down = (s_down+s_up)/2;
+ }
+ }
+
+ return 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));
+ }
+ return vertices;
+ }
+
+ fn generate_flow_graph(&self, size: u32, zone_to_id: &HashMap<String, usize>, exclude_assoc : &HashSet<(usize,usize)>) -> Result<Graph<FlowEdge>, String> {
+ let vertices = ClusterLayout::generate_graph_vertices(zone_to_id.len(),
+ self.useful_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), self.zone_redundancy as u32)?;
+ g.add_edge(Vertex::Source, Vertex::Pdown(p), (self.replication_factor - self.zone_redundancy) as u32)?;
+ 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 u32)?;
+ }
+ }
+ for n in 0..self.useful_nodes().len() {
+ let node_capacity = self.get_node_capacity(&self.node_id_vec[n])?;
+ let node_zone = zone_to_id[&self.get_node_zone(&self.node_id_vec[n])?];
+ g.add_edge(Vertex::N(n), Vertex::Sink, node_capacity/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)?;
+ }
+ }
+ }
+ return Ok(g);
+ }
+
+
+ fn compute_candidate_assignment(&self, zone_to_id: &HashMap<String, usize>,
+ old_assoc_opt : &Option<Vec< Vec<usize> >>) -> Result<Graph<FlowEdge>, String > {
+
+ //We list the edges that are not used in the old association
+ let mut exclude_edge = HashSet::<(usize,usize)>::new();
+ if let Some(old_assoc) = old_assoc_opt {
+ let nb_nodes = self.useful_nodes().len();
+ for p in 0..NB_PARTITIONS {
+ for n in 0..nb_nodes {
+ exclude_edge.insert((p,n));
+ }
+ for n in old_assoc[p].iter() {
+ exclude_edge.remove(&(p,*n));
+ }
+ }
+ }
+
+ //We compute the best flow using only the edges used in the old assoc
+ let mut g = self.generate_flow_graph(self.partition_size, zone_to_id, &exclude_edge )?;
+ g.compute_maximal_flow()?;
+ for (p,n) in exclude_edge.iter() {
+ let node_zone = zone_to_id[&self.get_node_zone(&self.node_id_vec[*n])?];
+ g.add_edge(Vertex::PZ(*p,node_zone), Vertex::N(*n), 1)?;
+ }
+ g.compute_maximal_flow()?;
+ return Ok(g);
+ }
+
+ fn minimize_rebalance_load(&self, gflow: &mut Graph<FlowEdge>, zone_to_id: &HashMap<String, usize>, old_assoc : &Vec< Vec<usize> >) -> Result<(), String > {
+ let mut cost = CostFunction::new();
+ for p in 0..NB_PARTITIONS {
+ for n in old_assoc[p].iter() {
+ let node_zone = zone_to_id[&self.get_node_zone(&self.node_id_vec[*n])?];
+ cost.insert((Vertex::PZ(p,node_zone), Vertex::N(*n)), -1);
+ }
+ }
+ let nb_nodes = self.useful_nodes().len();
+ let path_length = 4*nb_nodes;
+ gflow.optimize_flow_with_cost(&cost, path_length)?;
+
+ return Ok(());
+ }
+
+ fn update_ring_from_flow(&mut self, nb_zones : usize, gflow: &Graph<FlowEdge> ) -> Result<(), String>{
+ self.ring_assignation_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() {
+ match vertex{
+ Vertex::N(n) => self.ring_assignation_data.push((*n).try_into().unwrap()),
+ _ => ()
+ }
+ }
+ }
+ }
+
+ if self.ring_assignation_data.len() != NB_PARTITIONS*self.replication_factor {
+ return Err("Critical Error : the association ring we produced does not have the right size.".to_string());
+ }
+ return Ok(());
+ }
+
+
+ //This function returns a message summing up the partition repartition of the new
+ //layout.
+ fn output_stat(&self , gflow : &Graph<FlowEdge>,
+ old_assoc_opt : &Option< Vec<Vec<usize>> >,
+ zone_to_id: &HashMap<String, usize>,
+ id_to_zone : &Vec<String>) -> Result<Message, String>{
+ let mut msg = Message::new();
+
+ let nb_partitions = 1usize << PARTITION_BITS;
+ let used_cap = self.partition_size * nb_partitions as u32 *
+ self.replication_factor as u32;
+ let total_cap = self.get_total_capacity()?;
+ let percent_cap = 100.0*(used_cap as f32)/(total_cap as f32);
+ msg.push(format!("Available capacity / Total cluster capacity: {} / {} ({:.1} %)",
+ used_cap , total_cap , percent_cap ));
+ msg.push(format!("If the percentage is to low, it might be that the replication/redundancy constraints force the use of nodes/zones with small storage capacities.
+ You might want to rebalance the storage capacities or relax the constraints. See the detailed statistics below and look for saturated nodes/zones."));
+ msg.push(format!("Recall that because of the replication, the actual available storage capacity is {} / {} = {}.", used_cap , self.replication_factor , used_cap/self.replication_factor as u32));
+
+ //We define and fill in the following tables
+ let storing_nodes = self.useful_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.len() > 0 {
+ stored_partitions_zone[z] += 1;
+ }
+ for vert in pz_nodes.iter() {
+ if let Vertex::N(n) = *vert {
+ stored_partitions[n] += 1;
+ if let Some(old_assoc) = old_assoc_opt {
+ if !old_assoc[p].contains(&n) {
+ new_partitions[n] += 1;
+ }
+ }
+ }
+ }
+ if let Some(old_assoc) = old_assoc_opt {
+ let mut old_zones_of_p = Vec::<usize>::new();
+ for n in old_assoc[p].iter() {
+ old_zones_of_p.push(
+ zone_to_id[&self.get_node_zone(&self.node_id_vec[*n])?]);
+ }
+ if !old_zones_of_p.contains(&z) {
+ new_partitions_zone[z] += 1;
+ }
+ }
+ }
+ }
+
+ //We display the statistics
+
+ if *old_assoc_opt != None {
+ 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(format!(""));
+ msg.push(format!("Detailed statistics by zones and nodes."));
+
+ 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.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();
+ msg.push(format!(""));
+
+ if *old_assoc_opt != None {
+ msg.push(format!("Zone {}: {} distinct partitions stored ({} new, \
+ {} partition copies) ", id_to_zone[z], stored_partitions_zone[z],
+ new_partitions_zone[z], replicated_partitions));
+ }
+ else{
+ msg.push(format!("Zone {}: {} distinct partitions stored ({} partition \
+ copies) ",
+ id_to_zone[z], stored_partitions_zone[z], replicated_partitions));
+ }
+
+ let available_cap_z : u32 = self.partition_size*replicated_partitions as u32;
+ let mut total_cap_z = 0;
+ for n in nodes_of_z.iter() {
+ total_cap_z += self.get_node_capacity(&self.node_id_vec[*n])?;
+ }
+ let percent_cap_z = 100.0*(available_cap_z as f32)/(total_cap_z as f32);
+ msg.push(format!(" Available capacity / Total capacity: {}/{} ({:.1}%).",
+ available_cap_z, total_cap_z, percent_cap_z));
+ msg.push(format!(""));
+
+ for n in nodes_of_z.iter() {
+ let available_cap_n = stored_partitions[*n] as u32 *self.partition_size;
+ let total_cap_n =self.get_node_capacity(&self.node_id_vec[*n])?;
+ let tags_n = (self.node_role(&self.node_id_vec[*n])
+ .ok_or("Node not found."))?.tags_string();
+ msg.push(format!(" Node {}: {} partitions ({} new) ; \
+ available/total capacity: {} / {} ({:.1}%) ; tags:{}",
+ &self.node_id_vec[*n].to_vec().encode_hex::<String>(),
+ stored_partitions[*n],
+ new_partitions[*n], available_cap_n, total_cap_n,
+ (available_cap_n as f32)/(total_cap_n as f32)*100.0 ,
+ tags_n));
+ }
+ }
+
+ return Ok(msg);
+ }
+
}
+//====================================================================================
+
#[cfg(test)]
mod tests {
use super::*;
diff --git a/src/rpc/lib.rs b/src/rpc/lib.rs
index 392ff48f..1036a8e1 100644
--- a/src/rpc/lib.rs
+++ b/src/rpc/lib.rs
@@ -8,9 +8,11 @@ mod consul;
mod kubernetes;
pub mod layout;
+pub mod graph_algo;
pub mod ring;
pub mod system;
+
mod metrics;
pub mod rpc_helper;
diff --git a/src/rpc/ring.rs b/src/rpc/ring.rs
index 73a126a2..743a5cba 100644
--- a/src/rpc/ring.rs
+++ b/src/rpc/ring.rs
@@ -40,6 +40,7 @@ pub struct Ring {
// 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;
// The maximum number of times an object might get replicated
// This must be at least 3 because Garage supports 3-way replication
diff --git a/src/rpc/system.rs b/src/rpc/system.rs
index 68d94ea5..313671ca 100644
--- a/src/rpc/system.rs
+++ b/src/rpc/system.rs
@@ -97,6 +97,7 @@ pub struct System {
kubernetes_discovery: Option<KubernetesDiscoveryParam>,
replication_factor: usize,
+ zone_redundancy: usize,
/// The ring
pub ring: watch::Receiver<Arc<Ring>>,
@@ -192,6 +193,7 @@ impl System {
network_key: NetworkKey,
background: Arc<BackgroundRunner>,
replication_factor: usize,
+ zone_redundancy: usize,
config: &Config,
) -> Arc<Self> {
let node_key =
@@ -211,7 +213,7 @@ impl System {
"No valid previous cluster layout stored ({}), starting fresh.",
e
);
- ClusterLayout::new(replication_factor)
+ ClusterLayout::new(replication_factor, zone_redundancy)
}
};
@@ -285,6 +287,7 @@ impl System {
rpc: RpcHelper::new(netapp.id.into(), fullmesh, background.clone(), ring.clone()),
system_endpoint,
replication_factor,
+ zone_redundancy,
rpc_listen_addr: config.rpc_bind_addr,
rpc_public_addr,
bootstrap_peers: config.bootstrap_peers.clone(),
diff --git a/src/util/bipartite.rs b/src/util/bipartite.rs
deleted file mode 100644
index 1e1e9caa..00000000
--- a/src/util/bipartite.rs
+++ /dev/null
@@ -1,363 +0,0 @@
-/*
- * This module deals with graph algorithm in complete bipartite
- * graphs. It is used in layout.rs to build the partition to node
- * assignation.
- * */
-
-use rand::prelude::SliceRandom;
-use std::cmp::{max, min};
-use std::collections::VecDeque;
-
-//Graph data structure for the flow algorithm.
-#[derive(Clone, Copy, Debug)]
-struct EdgeFlow {
- c: i32,
- flow: i32,
- v: usize,
- rev: usize,
-}
-
-//Graph data structure for the detection of positive cycles.
-#[derive(Clone, Copy, Debug)]
-struct WeightedEdge {
- w: i32,
- u: usize,
- v: usize,
-}
-
-/* This function takes two matchings (old_match and new_match) in a
- * complete bipartite graph. It returns a matching that has the
- * same degree as new_match at every vertex, and that is as close
- * as possible to old_match.
- * */
-pub fn optimize_matching(
- old_match: &[Vec<usize>],
- new_match: &[Vec<usize>],
- nb_right: usize,
-) -> Vec<Vec<usize>> {
- let nb_left = old_match.len();
- let ed = WeightedEdge { w: -1, u: 0, v: 0 };
- let mut edge_vec = vec![ed; nb_left * nb_right];
-
- //We build the complete bipartite graph structure, represented
- //by the list of all edges.
- for i in 0..nb_left {
- for j in 0..nb_right {
- edge_vec[i * nb_right + j].u = i;
- edge_vec[i * nb_right + j].v = nb_left + j;
- }
- }
-
- for i in 0..edge_vec.len() {
- //We add the old matchings
- if old_match[edge_vec[i].u].contains(&(edge_vec[i].v - nb_left)) {
- edge_vec[i].w *= -1;
- }
- //We add the new matchings
- if new_match[edge_vec[i].u].contains(&(edge_vec[i].v - nb_left)) {
- (edge_vec[i].u, edge_vec[i].v) = (edge_vec[i].v, edge_vec[i].u);
- edge_vec[i].w *= -1;
- }
- }
- //Now edge_vec is a graph where edges are oriented LR if we
- //can add them to new_match, and RL otherwise. If
- //adding/removing them makes the matching closer to old_match
- //they have weight 1; and -1 otherwise.
-
- //We shuffle the edge list so that there is no bias depending in
- //partitions/zone label in the triplet dispersion
- let mut rng = rand::thread_rng();
- edge_vec.shuffle(&mut rng);
-
- //Discovering and flipping a cycle with positive weight in this
- //graph will make the matching closer to old_match.
- //We use Bellman Ford algorithm to discover positive cycles
- while let Some(cycle) = positive_cycle(&edge_vec, nb_left, nb_right) {
- for i in cycle {
- //We flip the edges of the cycle.
- (edge_vec[i].u, edge_vec[i].v) = (edge_vec[i].v, edge_vec[i].u);
- edge_vec[i].w *= -1;
- }
- }
-
- //The optimal matching is build from the graph structure.
- let mut matching = vec![Vec::<usize>::new(); nb_left];
- for e in edge_vec {
- if e.u > e.v {
- matching[e.v].push(e.u - nb_left);
- }
- }
- matching
-}
-
-//This function finds a positive cycle in a bipartite wieghted graph.
-fn positive_cycle(
- edge_vec: &[WeightedEdge],
- nb_left: usize,
- nb_right: usize,
-) -> Option<Vec<usize>> {
- let nb_side_min = min(nb_left, nb_right);
- let nb_vertices = nb_left + nb_right;
- let weight_lowerbound = -((nb_left + nb_right) as i32) - 1;
- let mut accessed = vec![false; nb_left];
-
- //We try to find a positive cycle accessible from the left
- //vertex i.
- for i in 0..nb_left {
- if accessed[i] {
- continue;
- }
- let mut weight = vec![weight_lowerbound; nb_vertices];
- let mut prev = vec![edge_vec.len(); nb_vertices];
- weight[i] = 0;
- //We compute largest weighted paths from i.
- //Since the graph is bipartite, any simple cycle has length
- //at most 2*nb_side_min. In the general Bellman-Ford
- //algorithm, the bound here is the number of vertices. Since
- //the number of partitions can be much larger than the
- //number of nodes, we optimize that.
- for _ in 0..(2 * nb_side_min) {
- for (j, e) in edge_vec.iter().enumerate() {
- if weight[e.v] < weight[e.u] + e.w {
- weight[e.v] = weight[e.u] + e.w;
- prev[e.v] = j;
- }
- }
- }
- //We update the accessed table
- for i in 0..nb_left {
- if weight[i] > weight_lowerbound {
- accessed[i] = true;
- }
- }
- //We detect positive cycle
- for e in edge_vec {
- if weight[e.v] < weight[e.u] + e.w {
- //it means e is on a path branching from a positive cycle
- let mut was_seen = vec![false; nb_vertices];
- let mut curr = e.u;
- //We track back with prev until we reach the cycle.
- while !was_seen[curr] {
- was_seen[curr] = true;
- curr = edge_vec[prev[curr]].u;
- }
- //Now curr is on the cycle. We collect the edges ids.
- let mut cycle = vec![prev[curr]];
- let mut cycle_vert = edge_vec[prev[curr]].u;
- while cycle_vert != curr {
- cycle.push(prev[cycle_vert]);
- cycle_vert = edge_vec[prev[cycle_vert]].u;
- }
-
- return Some(cycle);
- }
- }
- }
-
- None
-}
-
-// This function takes two arrays of capacity and computes the
-// maximal matching in the complete bipartite graph such that the
-// left vertex i is matched to left_cap_vec[i] right vertices, and
-// the right vertex j is matched to right_cap_vec[j] left vertices.
-// To do so, we use Dinic's maximum flow algorithm.
-pub fn dinic_compute_matching(left_cap_vec: Vec<u32>, right_cap_vec: Vec<u32>) -> Vec<Vec<usize>> {
- let mut graph = Vec::<Vec<EdgeFlow>>::new();
- let ed = EdgeFlow {
- c: 0,
- flow: 0,
- v: 0,
- rev: 0,
- };
-
- // 0 will be the source
- graph.push(vec![ed; left_cap_vec.len()]);
- for (i, c) in left_cap_vec.iter().enumerate() {
- graph[0][i].c = *c as i32;
- graph[0][i].v = i + 2;
- graph[0][i].rev = 0;
- }
-
- //1 will be the sink
- graph.push(vec![ed; right_cap_vec.len()]);
- for (i, c) in right_cap_vec.iter().enumerate() {
- graph[1][i].c = *c as i32;
- graph[1][i].v = i + 2 + left_cap_vec.len();
- graph[1][i].rev = 0;
- }
-
- //we add left vertices
- for i in 0..left_cap_vec.len() {
- graph.push(vec![ed; 1 + right_cap_vec.len()]);
- graph[i + 2][0].c = 0; //directed
- graph[i + 2][0].v = 0;
- graph[i + 2][0].rev = i;
-
- for j in 0..right_cap_vec.len() {
- graph[i + 2][j + 1].c = 1;
- graph[i + 2][j + 1].v = 2 + left_cap_vec.len() + j;
- graph[i + 2][j + 1].rev = i + 1;
- }
- }
-
- //we add right vertices
- for i in 0..right_cap_vec.len() {
- let lft_ln = left_cap_vec.len();
- graph.push(vec![ed; 1 + lft_ln]);
- graph[i + lft_ln + 2][0].c = graph[1][i].c;
- graph[i + lft_ln + 2][0].v = 1;
- graph[i + lft_ln + 2][0].rev = i;
-
- for j in 0..left_cap_vec.len() {
- graph[i + 2 + lft_ln][j + 1].c = 0; //directed
- graph[i + 2 + lft_ln][j + 1].v = j + 2;
- graph[i + 2 + lft_ln][j + 1].rev = i + 1;
- }
- }
-
- //To ensure the dispersion of the triplets generated by the
- //assignation, we shuffle the neighbours of the nodes. Hence,
- //left vertices do not consider the right ones in the same order.
- let mut rng = rand::thread_rng();
- for i in 0..graph.len() {
- graph[i].shuffle(&mut rng);
- //We need to update the ids of the reverse edges.
- for j in 0..graph[i].len() {
- let target_v = graph[i][j].v;
- let target_rev = graph[i][j].rev;
- graph[target_v][target_rev].rev = j;
- }
- }
-
- let nb_vertices = graph.len();
-
- //We run Dinic's max flow algorithm
- loop {
- //We build the level array from Dinic's algorithm.
- let mut level = vec![-1; nb_vertices];
-
- let mut fifo = VecDeque::new();
- fifo.push_back((0, 0));
- while !fifo.is_empty() {
- if let Some((id, lvl)) = fifo.pop_front() {
- if level[id] == -1 {
- level[id] = lvl;
- for e in graph[id].iter() {
- if e.c - e.flow > 0 {
- fifo.push_back((e.v, lvl + 1));
- }
- }
- }
- }
- }
- if level[1] == -1 {
- //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 = VecDeque::new();
-
- let flow_upper_bound = if let Some(x) = left_cap_vec.iter().max() {
- *x as i32
- } else {
- panic!();
- };
-
- lifo.push_back((0, flow_upper_bound));
-
- while let Some((id_tmp, f_tmp)) = lifo.back() {
- let id = *id_tmp;
- let f = *f_tmp;
- if id == 1 {
- //The DFS reached the sink, we can add a
- //residual flow.
- lifo.pop_back();
- while !lifo.is_empty() {
- if let Some((id, _)) = lifo.pop_back() {
- let nbd = next_nbd[id];
- graph[id][nbd].flow += f;
- let id_v = graph[id][nbd].v;
- let nbd_v = graph[id][nbd].rev;
- graph[id_v][nbd_v].flow -= f;
- }
- }
- lifo.push_back((0, flow_upper_bound));
- continue;
- }
- //else we did not reach the sink
- let nbd = next_nbd[id];
- if nbd >= graph[id].len() {
- //There is nothing to explore from id anymore
- lifo.pop_back();
- if let Some((parent, _)) = lifo.back() {
- next_nbd[*parent] += 1;
- }
- continue;
- }
- //else we can try to send flow from id to its nbd
- let new_flow = min(f, graph[id][nbd].c - graph[id][nbd].flow);
- if level[graph[id][nbd].v] <= level[id] || new_flow == 0 {
- //We cannot send flow to nbd.
- next_nbd[id] += 1;
- continue;
- }
- //otherwise, we send flow to nbd.
- lifo.push_back((graph[id][nbd].v, new_flow));
- }
- }
-
- //We return the association
- let assoc_table = (0..left_cap_vec.len())
- .map(|id| {
- graph[id + 2]
- .iter()
- .filter(|e| e.flow > 0)
- .map(|e| e.v - 2 - left_cap_vec.len())
- .collect()
- })
- .collect();
-
- //consistency check
-
- //it is a flow
- for i in 3..graph.len() {
- assert!(graph[i].iter().map(|e| e.flow).sum::<i32>() == 0);
- for e in graph[i].iter() {
- assert!(e.flow + graph[e.v][e.rev].flow == 0);
- }
- }
-
- //it solves the matching problem
- for i in 0..left_cap_vec.len() {
- assert!(left_cap_vec[i] as i32 == graph[i + 2].iter().map(|e| max(0, e.flow)).sum::<i32>());
- }
- for i in 0..right_cap_vec.len() {
- assert!(
- right_cap_vec[i] as i32
- == graph[i + 2 + left_cap_vec.len()]
- .iter()
- .map(|e| max(0, e.flow))
- .sum::<i32>()
- );
- }
-
- assoc_table
-}
-
-#[cfg(test)]
-mod tests {
- use super::*;
-
- #[test]
- fn test_flow() {
- let left_vec = vec![3; 8];
- let right_vec = vec![0, 4, 8, 4, 8];
- //There are asserts in the function that computes the flow
- let _ = dinic_compute_matching(left_vec, right_vec);
- }
-
- //maybe add tests relative to the matching optilization ?
-}
diff --git a/src/util/lib.rs b/src/util/lib.rs
index 891549c3..e83fc2e6 100644
--- a/src/util/lib.rs
+++ b/src/util/lib.rs
@@ -4,7 +4,6 @@
extern crate tracing;
pub mod background;
-pub mod bipartite;
pub mod config;
pub mod crdt;
pub mod data;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-10 10:44:04 +0000