Value of index.blocks.write is auto changed to false

Elastic Stack Elasticsearch
1

ES ver. 7.4

I want to block all write actions (create/update/delete) to my index. I need it to copy docs to another index using reindex action and keep 100% consistency between indicies.

So what I do is:

curl -X PUT \
  https://elasticsearch/foo-bar/_settings \
  -H 'Content-Type: application/json' \
  -d '{
	"index": {
		"blocks": {
			"write": true
		}
	}
}'

Then I verify it:

curl -X GET 'https://elasticsearch/foo-bar/_settings?include_defaults=true'

And the response is correct:

settings.index.blocks.write = true

But after some time about 1 min, this value changes automatically to false.

There is nothing in documentation about anything that manages this value: https://www.elastic.co/guide/en/elasticsearch/reference/master/index-modules-blocks.html

Does anyone know what happens, what change that value?

2

Ping...
Anyone ?

3

On top of my head no component should do that.

You can increase some logging to monitor when this is set by running

PUT /_cluster/settings
{
  "transient": {
    "logger.org.elasticsearch.cluster.service.MasterService": "debug"
  }
}

And check the master node logs. Don't forget to set this to INFO again...

Do you have any component like curator running?