# How can discovery.zen.minimum\_master\_nodes be unset in 2.0?

**URL:** <https://forum.opensearch.org/t/how-can-discovery-zen-minimum-master-nodes-be-unset-in-2-0/10081>\
**Category:** OpenSearch\
**Created:** [June 27, 2022, 9:46pm UTC](https://forum.opensearch.org/t/how-can-discovery-zen-minimum-master-nodes-be-unset-in-2-0/10081 "2022-06-27T21:46:01Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![mhoydis](https://avatars.discourse-cdn.com/v4/letter/m/c0e974/32.png) [@mhoydis](https://forum.opensearch.org/u/mhoydis)\
**Post date:** [June 27, 2022, 9:46pm UTC](https://forum.opensearch.org/t/how-can-discovery-zen-minimum-master-nodes-be-unset-in-2-0/10081/1 "2022-06-27T21:46:01Z")

</div>

In a fresh new 2.0.1 cluster, I ended up setting discovery.zen.minimum\_master\_nodes as part of a routine.

```auto
curl --insecure -u admin:redacted -X PUT "https://localhost:9200/_cluster/settings" -H 'Content-Type: application/json' -d'
{
    "persistent" : {
        "discovery.zen.minimum_master_nodes": 2
    }
}
'

```

The cluster initially accepted this.  
However, now any subsequent attempts to mess with \_cluster/settings is met with this error:

```auto
{"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"unknown setting [archived.discovery.zen.minimum_master_nodes] please check that any required plugins are installed, or check the breaking changes documentation for removed settings"}],"type":"illegal_argument_exception","reason":"unknown setting [archived.discovery.zen.minimum_master_nodes] please check that any required plugins are installed, or check the breaking changes documentation for removed settings"},"status":400}

```

…and my change is not actually taken.

OK, no biggie, right? We’ll just remove discovery.zen.minimum\_master\_nodes by setting it to null, yeah?

```auto
curl --insecure -u admin:redacted -X PUT "https://localhost:9200/_cluster/settings" -H 'Content-Type: application/json' -d'
{
    "persistent" : {
        "discovery.zen.minimum_master_nodes": null
    }
}
'

```

**…well, that doesn’t work.** I get the same error message as before.  
(I tried to same with archived.discovery.zen.minimum\_master\_nodes, too.).

So, I’m stuck in quite the pickle. I’ve set an “unknown” setting into \_cluster/settings, and now cannot remove it, because any attempt to PUT anything to \_cluster/settings throws an error about the old zen setting that is set.

Any ideas how I might proceed? This seems like quite the catch-22.

---

<div class="post-metadata">

**Author:** ![reta](https://avatars.discourse-cdn.com/v4/letter/r/cdc98d/32.png) [@reta](https://forum.opensearch.org/u/reta)\
**Post date:** [June 28, 2022, 2:25pm UTC](https://forum.opensearch.org/t/how-can-discovery-zen-minimum-master-nodes-be-unset-in-2-0/10081/2 "2022-06-28T14:25:49Z")

</div>

Hey @mhoydis ,

`Zen1` discovery has been deprecated for a while and was removed in 2.0, check the respective change [1] please. Thank you.

[1] [https://github.com/opensearch-project/OpenSearch/pull/1216](https://github.com/opensearch-project/OpenSearch/pull/1216)

---

<div class="post-metadata">

**Author:** ![mhoydis](https://avatars.discourse-cdn.com/v4/letter/m/c0e974/32.png) [@mhoydis](https://forum.opensearch.org/u/mhoydis)\
**Post date:** [June 28, 2022, 2:33pm UTC](https://forum.opensearch.org/t/how-can-discovery-zen-minimum-master-nodes-be-unset-in-2-0/10081/3 "2022-06-28T14:33:41Z")

</div>

Thanks, I understand that that the discovery.zen.minimum\_master\_nodes is removed from Opensearch.  
However, my question is about how to repair my cluster which has accidentally received the removed setting.  
The fact that I accidentally included a setting related to an archived feature is irrelevant to the situation. The problem is there doesn’t seem to be a way to remove these specific blacklisted settings from the cluster state if it happens to make its way in there.  
As it is now, this seems to be a very easy way to hose a cluster. I can’t do anything with the \_cluster/settings API at this point. The only path I can see forward is to manually delete the cluster state from disk… obviously less than ideal.

---

<div class="post-metadata">

**Author:** ![reta](https://avatars.discourse-cdn.com/v4/letter/r/cdc98d/32.png) [@reta](https://forum.opensearch.org/u/reta)\
**Post date:** [June 28, 2022, 8:47pm UTC](https://forum.opensearch.org/t/how-can-discovery-zen-minimum-master-nodes-be-unset-in-2-0/10081/4 "2022-06-28T20:47:06Z")

</div>

Oh got it, thank you @mhoydis , so basically the issue is: because of this removed setting the updates to the cluster settings are not going through, correct? I think it is worth opening an issue here [1] since the migration process should not render clusters unusable because of that. Thank you.

[1] [https://github.com/opensearch-project/OpenSearch/issues](https://github.com/opensearch-project/OpenSearch/issues)

---

<div class="post-metadata">

**Author:** ![mhoydis](https://avatars.discourse-cdn.com/v4/letter/m/c0e974/32.png) [@mhoydis](https://forum.opensearch.org/u/mhoydis)\
**Post date:** [June 28, 2022, 8:59pm UTC](https://forum.opensearch.org/t/how-can-discovery-zen-minimum-master-nodes-be-unset-in-2-0/10081/5 "2022-06-28T20:59:44Z")

</div>

Correct. Because a value for this setting has been set, no further changes to any other setting is allowed, including a change that would remove the offending value. An (apparently?) uncorrectable situation.