Introduction

In Elasticsearch ecosystem, it can be immensely useful to monitor nodes and cluster to manage and improve their performance and state. There are several issues that can arise at cluster level, such as:

• Node overheads, where some nodes can have too many shards allocated and can become a bottleneck for the entire cluster

• Node shutdown can happen due to many reasons, for example, full disks, hardware failures, and power problems

• Shard relocation problems or corruptions, in which some shards are unable to get an online status

• Too large shards happens when a shard is too big; the index performance decreases due to Lucene massive segments merging

• Empty indices and shards waste memory and resources, but because every shard has a lot of active threads if there is a huge number of unused indices and shards, the general cluster performance is degraded

• Node problems such as high CPU usage or disk full

Detecting malfunction or bad performances can be done via API or via some frontends that are...