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Full cluster restart upgrade
editFull cluster restart upgrade
editElasticsearch requires a full cluster restart when upgrading across major versions. Rolling upgrades are not supported across major versions. Consult this table to verify that a full cluster restart is required.
The process to perform an upgrade with a full cluster restart is as follows:
-
Disable shard allocation
When you shut down a node, the allocation process will immediately try to replicate the shards that were on that node to other nodes in the cluster, causing a lot of wasted I/O. This can be avoided by disabling allocation before shutting down a node:
PUT _cluster/settings { "persistent": { "cluster.routing.allocation.enable": "none" } }
-
Perform a synced flush
Shard recovery will be much faster if you stop indexing and issue a synced-flush request:
POST _flush/synced
A synced flush request is a “best effort” operation. It will fail if there are any pending indexing operations, but it is safe to reissue the request multiple times if necessary.
-
Shutdown and upgrade all nodes
Stop all Elasticsearch services on all nodes in the cluster. Each node can be upgraded following the same procedure described in Stop and upgrade a single node.
-
Upgrade any plugins
Elasticsearch plugins must be upgraded when upgrading a node. Use the
elasticsearch-plugin
script to install the correct version of any plugins that you need. -
Start the cluster
If you have dedicated master nodes — nodes with
node.master
set totrue
(the default) andnode.data
set tofalse
— then it is a good idea to start them first. Wait for them to form a cluster and to elect a master before proceeding with the data nodes. You can check progress by looking at the logs.As soon as the minimum number of master-eligible nodes have discovered each other, they will form a cluster and elect a master. From that point on, the
_cat/health
and_cat/nodes
APIs can be used to monitor nodes joining the cluster:GET _cat/health GET _cat/nodes
Use these APIs to check that all nodes have successfully joined the cluster.
-
Wait for yellow
As soon as each node has joined the cluster, it will start to recover any primary shards that are stored locally. Initially, the
_cat/health
request will report astatus
ofred
, meaning that not all primary shards have been allocated.Once each node has recovered its local shards, the
status
will becomeyellow
, meaning all primary shards have been recovered, but not all replica shards are allocated. This is to be expected because allocation is still disabled. -
Reenable allocation
Delaying the allocation of replicas until all nodes have joined the cluster allows the master to allocate replicas to nodes which already have local shard copies. At this point, with all the nodes in the cluster, it is safe to reenable shard allocation:
PUT _cluster/settings { "persistent": { "cluster.routing.allocation.enable": "all" } }
The cluster will now start allocating replica shards to all data nodes. At this point it is safe to resume indexing and searching, but your cluster will recover more quickly if you can delay indexing and searching until all shards have recovered.
You can monitor progress with the
_cat/health
and_cat/recovery
APIs:GET _cat/health GET _cat/recovery
Once the
status
column in the_cat/health
output has reachedgreen
, all primary and replica shards have been successfully allocated.