I have a 3 node Elasticsearch cluster. All 3 nodes are master, ingest and data nodes. I shutdown one of the nodes. As expected, the cluster goes into a yellow state. If I query the cluster using the following "_cat/shards" REST API command, I can see a single record being returned. The record returned is related to initializing a replica shard.
curl my_ip_address:9200/_cat/shards?pretty -u elastic | grep INITIALIZING
I later brought the shutdown node back online. After about 30 minutes, the cluster goes from yellow back into the green state.
My question, is there another "more detailed" method to see progress on the INITIALIZING shard?