This commit adds functionality so that aliases that are manipulated on
leader indices are replicated by the shard follow tasks to the follower
indices. Note that we ignore write indices. This is due to the fact that
follower indices do not receive direct writes so the concept is not
useful.
Relates #41815
This commit modifies the put follow index action to use a
CcrRepository when creating a follower index. It routes
the logic through the snapshot/restore process. A
wait_for_active_shards parameter can be used to configure
how long to wait before returning the response.
For each remote cluster the auto follow coordinator, starts an auto
follower that checks the remote cluster state and determines whether an
index needs to be auto followed. The time since last auto follow is
reported per remote cluster and gives insight whether the auto follow
process is alive.
Relates to #33007
Originates from #35895
This commit fixes two issues with the CCR API specification:
- remove the CCR stats endpoint, it is not currently implemented
- fix the documentation links