CODEWITHSUNDEEP
elasticsearchcluster-computingreplicationsharding
Stephen
Stephen

Reputation: 3465

Why No shard becomes primary on second node when it is UP again?

I have configured two node cluster and created an index with 4 shards and 1 replica enter image description here

Elastic created 2 primary shards on each node, this is how it looks from head plugin. shard 1, shard 3 are primary on node 1(stephen1c7) AND shard 0 and shard 2 are primary on node 2(stephen2c7)

enter image description here

Shutdown one Node

Now i have shutdown the node 2(stephen2c7) to see if all the shards on node 1(stephen1c7) became primary. Yes, all shards are now primary.

enter image description here

UP the shutdown node

Now i have made the Node 2(stephen2c7) up again to see if any shards on this node will be primary. But surprisingly no shard on this node became primary. Waited for long time but still no shard is primary on Node 2. Why so?

enter image description here

Is there any configuration to set for making the shards primary again after a node is up?

Thanks in advance!

Upvotes: 2

Views: 174

Answers (1)

Adonis
Adonis

Reputation: 4808

Given this post and this one (albeit slightly old),balancing the primary and replica shard across the cluster does not seem to be a priority in an Elastic cluster. As you can see, Elastic sees replica and primary shard and thus the status seems satisfactory for the cluster.

What I would suggest is to have a look at the shard balancing heuristic and play with these values until you obtain a satisfactory result. (as is often the case with ElasticSearch, testing several parameters is what will yield the best configuration given your architectural design choices).

Note that if you start using shard balancing heuristic, you might not get good results if you use at the same time shard filtering or forced awareness

Upvotes: 1

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