anchor.diff:  == Cluster Health
   
   The cluster health API allows to get a very simple status on the health
  -of the cluster.
  +of the cluster. For example, on a single node cluster with a single index
  +with 5 shards and one replica, this:
   
   [source,js]
   --------------------------------------------------
  -$ curl -XGET 'http://localhost:9200/_cluster/health?pretty=true'
  +GET _cluster/health
  +--------------------------------------------------
  +// CONSOLE
  +// TEST[s/^/PUT test1\n/]
  +
  +Returns this:
  +--------------------------------------------------
   {
     "cluster_name" : "testcluster",
  -  "status" : "green",
  +  "status" : "yellow",
     "timed_out" : false,
  -  "number_of_nodes" : 2,
  -  "number_of_data_nodes" : 2,
  +  "number_of_nodes" : 1,
  +  "number_of_data_nodes" : 1,
     "active_primary_shards" : 5,
  -  "active_shards" : 10,
  +  "active_shards" : 5,
     "relocating_shards" : 0,
     "initializing_shards" : 0,
  -  "unassigned_shards" : 0,
  +  "unassigned_shards" : 5,
     "delayed_unassigned_shards": 0,
     "number_of_pending_tasks" : 0,
     "number_of_in_flight_fetch": 0,
     "task_max_waiting_in_queue_millis": 0,
  -  "active_shards_percent_as_number": 100
  +  "active_shards_percent_as_number": 50.0
   }
   --------------------------------------------------
  +// TESTRESPONSE[s/testcluster/docs_integTest/]
   
   The API can also be executed against one or more indices to get just the
   specified indices health:
   
   [source,js]
   --------------------------------------------------
  -$ curl -XGET 'http://localhost:9200/_cluster/health/test1,test2'
  +GET /_cluster/health/test1,test2
   --------------------------------------------------
  +// CONSOLE
  +// TEST[s/^/PUT test1\nPUT test2\n/]
   
   The cluster health status is: `green`, `yellow` or `red`. On the shard
   level, a `red` status indicates that the specific shard is not allocated
  
positive.code: 
  [source,js]
  --------------------------------------------------
  $ curl -XGET 'http://localhost:9200/_cluster/health?wait_for_status=yellow&timeout=50s'
  --------------------------------------------------
  
  [float]
  [[request-params]]
  
negative.code: 
  [source,js]
  --------------------------------------------------
  GET /_cluster/health/twitter?level=shards
  --------------------------------------------------
  // CONSOLE
  // TEST[setup:twitter]
  