Unassigned ilm-history shard cluster in RED state

Elastic Stack Elasticsearch
1

dufing upgrade 7.4.2 -> 7.9 I received an error

"failed shard on node [GnAJTEqpTeyawpDyUli4Aw]: failed to create index, failure IllegalArgumentException[unknown setting [index.hidden] please check that any required plugins are installed, or check the breaking changes documentation for removed settings]",

shard has exceeded the maximum number of retries [5] on failed allocation attempts - manually call [/_cluster/reroute?retry_failed=true]

so I executed recommended command:

 curl -X POST  -u elastic:xxxxxxx "http://localhost:9200/_cluster/reroute?retry_failed=true"

but cluster become RED state!!!

curl -XGET -u elastic:xxxxxx "http://localhost:9200/_cat/health"
1598883387 14:16:27 corp-cz-cem red 21 17 1336 711 0 0 2 0 - 99.9%

I found this shards are unallocated

curl -s -XGET -u elastic:xxxxxx "http://localhost:9200/_cat/shards"  |grep -v STARTED
ilm-history-2-000001               0 p UNASSIGNED
ilm-history-2-000001               0 r UNASSIGNED

please could you help?
my production cluster is down and I am looking for any solution

2

resolved by
i do not know why this has happended byt
I could just delete the shards and problem resolved.

DELETE ilm-history-2-000001

3

This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.