CODEWITHSUNDEEP
elasticsearch
Nikhil
Nikhil

Reputation: 3152

How do I figure out the new master node when my master node fails in ElasticSearch?

Let's say I have 3 nodes. 1 of which is the master.

I have an API (running on another machine) which hits the master and gets my search result. This is through a subdomain, say s1.mydomain.com:9200 (assume the others are pointed to by s2.mydomain.com and s3.mydomain.com).

Now my master fails for whatever reason. How would my API recover from such a situation? Can I hit either S2 or S3 instead? How can I figure out what the new master is? Is there a predictable way to know which one would be picked as the new master should the master go down?

I've googled this and it's given me enough information about how when a master goes down, a failover is picked as the new master but I haven't seen anything clarify how I would need to handle this from the outside looking in.

Upvotes: 1

Views: 212

Answers (1)

Louis-Philippe Huberdeau
Louis-Philippe Huberdeau

Reputation: 5431

The master in ElasticSearch is really only for internal coordination. There are no actions required when a node goes down, other than trying to get it back up to get your full cluster performance back.

You can read/write to any of the remaining nodes and the data replication will keep going. When the old master node comes back up, it will re-join the cluster once it has received the updated data. In fact, you never need to worry if the node you are writing on is the master node.

There are some advanced configurations to alter these behaviors, but ElasticSearch comes with suitable defaults.

Upvotes: 2

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