Comment 0 for bug 1536689

The number_of_replicas is not correct for existing indices after scaling the ES cluster.

This is particularly critical for the index 'kibana-int': when starting with one node and scaling up the cluster to 3 nodes the HA is not ensured (number_of_replicas still to zero) and leads to lost Kibana dashboards if the primary node is down/crashed.

The plugin must re-configure dynamically this setting:
https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-update-settings.html

Other indices (log-* and notifications-*) will get the correct number_of_replicas the next day of the scale up but the current and older indices won't, hence there won't be HA.

The scale down case is olso impacted in this way: the health of the cluster will be yellow (warning) because the number_of_replicas cannot be honored (greater than the number of available nodes).