Elasticsearch Engine Layer
The tests associated with this layer help administrators to measure the availability of the Elasticsearch server and health of the Elasticsearch cluster at shards level. This way, administrators are proactively alerted when the server connectivity failures occur and health of the cluster goes down. Besides, administrators can also measure the usage of threads, count of active threads in each thread pool and the number of threads made to wait in queue.
Figure 1 : The Elasticsearch Server layer