Elasticseach failed shard allocation

Elastic Stack Elasticsearch
1

My ES is in yellow state after another one node adding and restarting cluster. I have 4 unassigned shards (from 33), and here is response for one of unassigned shards:

{
  "index" : "MY INDEX NAME",
  "shard" : 0,
  "primary" : false,
  "current_state" : "unassigned",
  "unassigned_info" : {
    "reason" : "ALLOCATION_FAILED",
    "at" : "2021-04-29TTIME",
    "failed_allocation_attempts" : 5,
    "details" : "failed shard on node [9yWBUCXXXTIIbiA]: failed to create index,     failure  IllegalArgumentException[IOException while reading synonyms_path_path: /etc/elasticsearch/synonyms.txt]; nested: NoSuchFileException[/etc/elasticsearch/synonyms.txt]; ",
    "last_allocation_status" : "no_attempt"
  },

How I can fix it?

2

You need to make sure that the synonym file is available on all machines.

3

Yeah, looks like this is the reason, new VM does not have this file.

Should I restart ES on all nodes after that? Or do something else?

4

@dadoonet add file and restarted ES, but looks like I need to run allocation again? Is it possible?

5

Did you restart everything? What is the error now?

6
  1. Added missing file
  2. Restarted ES
  3. Run POST /_cluster/reroute?retry_failed=true to start again allocation (I used Kibana Dev Toosl)

@dadoonet thank you for your help!

7

So it's all good now?

8

Yeah, after run POST /_cluster/reroute?retry_failed=true cluaster became green (after allocation)!