readiness probe not cover left node

[JaydenHan1106]

Hi all,
Readiness probe is "Get 9200 port" now. When es node left cluster(such as network problem), readiness probe still return ok, so request still can arrive left node. It's not our expect.

[thbkrkr]

The Elasticsearch readiness probe was designed to:

• allow for reads without a master
• improve availability for some search heavy use cases

History of changes on this probe:

1. /_cat/master => / # increase availiblity and favor search requests (Simplify the readiness check  #617 / PR Simplify ES readiness by requesting / instead of /_cat/master #626)
2. / => _cat/nodes?local # don't break change budget (Pod readiness based on cluster availability breaks change budget #1748 / PR Bind ES Pod readiness to a node-local endpoint #1777)
3. _cat/nodes?local => / # don't fail if a single node is stuck (Elasticsearch readiness probe might fail if a single node is stuck #2248 / PR Fix readiness probe #2272)