Elasticsearch: Inconsistent number of shards in stats & cluster APIs - elasticsearch

Question

I uploaded the data to my single node cluster and named the index as 'gequest'.
When I GET from http://localhost:9200/_cluster/stats?human&pretty, I get:
"cluster_name" : "elasticsearch",
"status" : "yellow",
"indices" : {
"count" : 1,
"shards" : {
"total" : 5,
"primaries" : 5,
"replication" : 0.0,
"index" : {
"shards" : {
"min" : 5,
"max" : 5,
"avg" : 5.0
},
"primaries" : {
"min" : 5,
"max" : 5,
"avg" : 5.0
},
"replication" : {
"min" : 0.0,
"max" : 0.0,
"avg" : 0.0
}
}
}
When I do GET on http://localhost:9200/_stats?pretty=true
"_shards" : {
"total" : 10,
"successful" : 5,
"failed" : 0
}
How come total number of shards not consistent in two reports? Why total shards are 10 from stats API. How to track the other 5?

Answer 1

From the results it is likely that you have a single elasticsearch node running and created a index with default values(which creates 5 shards and one replica). Since there is only one node running elasticsearch is unable to assign the replica shards anywhere(elasticsearch will never assign the primary and replica of the same shard in a single node).
The _cluster/stats API gives information about the cluster including the current state. From your result it is seen that the cluster state is "yellow" indicating that all the primary shards are allocated but not all replicas have been allocated/initialized. So it is showing only the allocated shards as 5.
The _stats API gives information about your indices in the cluster. It will give information about how many shards the index will have and how many replicas. Since your index needs a total of 10 shards (5 primary and 5 replica as specified when you create the index) the stats contain information as total 10, successful 5 and failed 5(failed because unable to allocate in any node).
Use http://localhost:9200/_cat/shards to see the overall shard status