auto_create_index persistent setting not dynamically updateable

[nielsbuyens]

Elasticsearch version (bin/elasticsearch --version):
version": {
"number": "5.5.2",
"build_hash": "b2f0c09",
"build_date": "2017-08-14T12:33:14.154Z",
"build_snapshot": false,
"lucene_version": "6.6.0"
}
Plugins installed: [x-pack 5.5.2 (monitoring)]

JVM version (java -version):
openjdk version "1.8.0_141"
OpenJDK Runtime Environment (build 1.8.0_141-b16)
OpenJDK 64-Bit Server VM (build 25.141-b16, mixed mode)

OS version (uname -a if on a Unix-like system):
Linux redacted 3.10.0-327.13.1.el7.x86_64 #1 SMP Thu Mar 31 16:04:38 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Description of the problem including expected versus actual behavior:
After setting the action.auto_create_index setting to false using the cluster update api, you can not change this setting anymore.
This means that if I set it to false, but later want to change it to for example still allow logstash indices to be created automatically ("+logstash*,-*), I can not do this anymore and get the following error:
persistent setting [action.auto_create_index], not dynamically updateable
The only way I found to make sure I could autocreate logstash indices again was to take the cluster down, remove the global state file from all nodes and restart the cluster.
This is also the case for "destructive_requires_name" and maybe more, but I haven't used any other settings currently.
Is this intended behavior?

Steps to reproduce:

curl -XPUT "http://localhost:9200/_cluster/settings" -H 'Content-Type: application/json' -d'
{
"persistent" : {
"auto_create_index": "false"
}
}'

Should be acknowledged: True

curl -XPUT "http://localhost:9200/_cluster/settings" -H 'Content-Type: application/json' -d'
{
"persistent" : {
"auto_create_index": "+logstash*,-*"
}
}'

Gives error:
persistent setting [action.auto_create_index], not dynamically updateable

[ywelsch]

The first update command should have failed already. Are you sure that it succeeded? I cannot reproduce this on a fresh ES 5.5.2 installation.
You can only set action.auto_create_index in your elasticsearch.yml file and need to restart the nodes for the setting to take effect.

[nielsbuyens]

Yes, I am allowed to run it, the documentation also indicates that it should be possible:

Automatic index creation can be disabled by setting action.auto_create_index to false in the config file of all nodes, or via the cluster update settings API.

[ywelsch]

ok, you have to use action.auto_create_index as setting name, not just auto_create_index.

I got confused earlier, because the setting used to be non-dynamic in 2.x