Clearing cache on stack with read only indices

Elastic Stack Elasticsearch
1

Hi,

I have system (ES 7.6.2) with many read only indices (index.blocks.read_only=true). All works fine but when I want to clear cache (curl -X POST "localhost:9200/_cache/clear") then I'm getting a lot of errors "index [ranking_202002] blocked by: [FORBIDDEN/5/index read-only (api)];". Any reason for that or this is bug in ES?

Kind regards -
Krzysztof Ksiezyk

2

You probably want to use index.blocks.write rather than index.blocks.read_only. The read-only block doesn't allow metadata changes, including clearing the cache, but it sounds like you only want to block writes.

3

I know about index.blocks.write and differences with "read_only" but it's more convenient for me to use read_only as it protects also against incidental removing or messing with index aliases. Just didn't see any connection between index metadata and cluster cache so asked this question