What does the Datanode roles do?

Graylog Central (peer support)
1

Hello,

I recently installed a graylog cluster with a datanode cluster (not a self managed opensearch).
When starting a datanode I got the following message in the logs:
Unable to initialize the search-data node: Missing value for configuration node.search.cache.size

Even if I set the node_search_cache_size, it would not work, so I removed the search role and it starts normally.

When looking at the documentation, I couldn’t find any information on what the search role does precisely (and the other roles too).

So I was wondering, what does the search role (and others roles) do ?

2

Datanode is using opensearch under the hood, you can read about the different roles here, although many are not used or only used in enterprise graylog. OpenSearch Node Roles: How to Configure all Node Roles

The search role is only used in enterprise graylog for warm tier, so in open it would be fine to disable, although I’ve never seen that error, so it is strange and may mean something else is wrong.

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