Nagios, now known as Nagios Core, is a free and Open Source monitoring tool, that monitors systems, networks and infrastructure.
With Nagios, you can monitor your remote hosts and their services remotely on a single window.
The elasticsearch bulk API makes it possible to perform many insert/update/index/delete operations in a single API call. This can greatly increase the indexing speed.
Clients supports for bulk API requests
Some of the officially supported clients provide helpers to assist with bulk API requests.