We are installing ES 5.x on linux and facing issues related to below settings.
max_map_count - Doc says it should set to 262144(https://www.elastic.co/guide/en/elasticsearch/reference/current/vm-max-map-count.html)
file descriptors - Doc says it should be 65,536 or higher (https://www.elastic.co/guide/en/elasticsearch/reference/current/file-descriptors.html)
number of threads - Doc says it should be at least 2048 (https://www.elastic.co/guide/en/elasticsearch/reference/master/max-number-of-threads.html)
We have done these changes as per documentation and things are working fine.
We just want to confirm that all these settings are mandatory OR is there any alternative to it.