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diff --git a/content/documentation/working_documents/migration_04.md b/content/documentation/working_documents/migration_04.md deleted file mode 100644 index 92ec71e..0000000 --- a/content/documentation/working_documents/migration_04.md +++ /dev/null @@ -1,110 +0,0 @@ -+++ -title="Doc Post" -date=2018-08-20 -+++ - -# Migrating from 0.3 to 0.4 - -**Migrating from 0.3 to 0.4 is unsupported. This document is only intended to -document the process internally for the Deuxfleurs cluster where we have to do -it. Do not try it yourself, you will lose your data and we will not help you.** - -**Migrating from 0.2 to 0.4 will break everything for sure. Never try it.** - -The internal data format of Garage hasn't changed much between 0.3 and 0.4. -The Sled database is still the same, and the data directory as well. - -The following has changed, all in the meta directory: - -- `node_id` in 0.3 contains the identifier of the current node. In 0.4, this - file does nothing and should be deleted. It is replaced by `node_key` (the - secret key) and `node_key.pub` (the associated public key). A node's - identifier on the ring is its public key. - -- `peer_info` in 0.3 contains the list of peers saved automatically by Garage. - The format has changed and it is now stored in `peer_list` (`peer_info` - should be deleted). - -When migrating, all node identifiers will change. This also means that the -affectation of data partitions on the ring will change, and lots of data will -have to be rebalanced. - -- If your cluster has only 3 nodes, all nodes store everything, therefore nothing has to be rebalanced. - -- If your cluster has only 4 nodes, for any partition there will always be at - least 2 nodes that stored data before that still store it after. Therefore - the migration should in theory be transparent and Garage should continue to - work during the rebalance. - -- If your cluster has 5 or more nodes, data will disappear during the - migration. Do not migrate (fortunately we don't have this scenario at - Deuxfleurs), or if you do, make Garage unavailable until things stabilize - (disable web and api access). - - -The migration steps are as follows: - -1. Prepare a new configuration file for 0.4. For each node, point to the same - meta and data directories as Garage 0.3. Basically, the things that change - are the following: - - - No more `rpc_tls` section - - You have to generate a shared `rpc_secret` and put it in all config files - - `bootstrap_peers` has a different syntax as it has to contain node keys. - Leave it empty and use `garage node-id` and `garage node connect` instead (new features of 0.4) - - put the publicly accessible RPC address of your node in `rpc_public_addr` if possible (its optional but recommended) - - If you are using Consul, change the `consul_service_name` to NOT be the name advertised by Nomad. - Now Garage is responsible for advertising its own service itself. - -2. Disable api and web access for some time (Garage does not support disabling - these endpoints but you can change the port number or stop your reverse - proxy for instance). - -3. Do `garage repair -a --yes tables` and `garage repair -a --yes blocks`, - check the logs and check that all data seems to be synced correctly between - nodes. - -4. Save somewhere the output of `garage status`. We will need this to remember - how to reconfigure nodes in 0.4. - -5. Turn off Garage 0.3 - -6. Backup metadata folders if you can (i.e. if you have space to do it - somewhere). Backuping data folders could also be usefull but that's much - harder to do. If your filesystem supports snapshots, this could be a good - time to use them. - -7. Turn on Garage 0.4 - -8. At this point, running `garage status` should indicate that all nodes of the - previous cluster are "unavailable". The nodes have new identifiers that - should appear in healthy nodes once they can talk to one another (use - `garage node connect` if necessary`). They should have NO ROLE ASSIGNED at - the moment. - -9. Prepare a script with several `garage node configure` commands that replace - each of the v0.3 node ID with the corresponding v0.4 node ID, with the same - zone/tag/capacity. For example if your node `drosera` had identifier `c24e` - before and now has identifier `789a`, and it was configured with capacity - `2` in zone `dc1`, put the following command in your script: - -```bash -garage node configure 789a -z dc1 -c 2 -t drosera --replace c24e -``` - -10. Run your reconfiguration script. Check that the new output of `garage - status` contains the correct node IDs with the correct values for capacity - and zone. Old nodes should no longer be mentioned. - -11. If your cluster has 4 nodes or less, and you are feeling adventurous, you - can reenable Web and API access now. Things will probably work. - -12. Garage might already be resyncing stuff. Issue a `garage repair -a --yes - tables` and `garage repair -a --yes blocks` to force it to do so. - -13. Wait for resyncing activity to stop in the logs. Do steps 12 and 13 two or - three times, until you see that when you issue the repair commands, nothing - gets resynced any longer. - -14. Your upgraded cluster should be in a working state. Re-enable API and Web - access and check that everything went well. |