Status endpoint should indicate if a node is running a reindex in Confluence Data Center

Replicable in DC: Yes.

Problem statement

The /status endpoint in Confluence Data Center does not indicate if a node is running a reindexing process. Instead, it returns:

{"state":"RUNNING"}

Solution

This endpoint should return MAINTENANCE when a reindex is running.

Why this is important

Reindexing is a heavy task, which can lead to performance degradation on the node. It also leads to inconsistent search results while it is being rebuilt.
Returning MAINTENANCE status would result in the load balancer removing that node from the rotation, to avoid users accessing it while the index is being built.

Jira already has that feature too, so it would be good for product parity:

• https://jira.atlassian.com/browse/JRASERVER-66970