Create an index with the same name as an alias results in illegal_argument_exception for any action

[salvob41]

Elasticsearch Version

v8.5

Installed Plugins

No response

Java Version

bundled

OS Version

any

Problem Description

You could create a a elasticsearch index with the same name of an alias without error. But this will result in a state in which you cannot make any actions on said index. In fact an action like

DELETE <index>

will result in...

{
  "error": {
    "root_cause": [
      {
        "type": "illegal_argument_exception",
        "reason": "The provided expression [mydata] matches an alias, specify the corresponding concrete indices instead."
      }
    ],
    "type": "illegal_argument_exception",
    "reason": "The provided expression [mydata] matches an alias, specify the corresponding concrete indices instead."
  },
  "status": 400
}

Restarting the node will not be succesfull, and there will be the following error:

2022-12-04 15:41:49 {"@timestamp":"2022-12-04T14:41:49.675Z", "log.level":"ERROR", "message":"fatal exception while booting Elasticsearch", "ecs.version": "1.2.0","service.name":"ES_ECS","event.dataset":"elasticsearch.server","process.thread.name":"main","log.logger":"org.elasticsearch.bootstrap.Elasticsearch","elasticsearch.node.name":"9c6f45711d60","elasticsearch.cluster.name":"docker-cluster","error.type":"java.lang.IllegalStateException","error.message":"index, alias, and data stream names need to be unique, but the following duplicates were found [mydata (alias of [mydata/1Y69sJxZT1qIkKnM-w4ERA]) conflicts with index]","error.stack_trace":"java.lang.IllegalStateException: index, alias, and data stream names need to be unique, but the following duplicates were found [mydata (alias of [mydata/1Y69sJxZT1qIkKnM-w4ERA]) conflicts with index]\n\tat [email protected]/org.elasticsearch.cluster.metadata.Metadata$Builder.ensureNoNameCollisions(Metadata.java:2225)\n\tat [email protected]/org.elasticsearch.cluster.metadata.Metadata$Builder.build(Metadata.java:2135)\n\tat [email protected]/org.elasticsearch.cluster.metadata.Metadata$Builder.build(Metadata.java:2071)\n\tat [email protected]/org.elasticsearch.gateway.PersistedClusterStateService.loadOnDiskState(PersistedClusterStateService.java:618)\n\tat [email protected]/org.elasticsearch.gateway.PersistedClusterStateService.loadBestOnDiskState(PersistedClusterStateService.java:465)\n\tat [email protected]/org.elasticsearch.gateway.PersistedClusterStateService.loadBestOnDiskState(PersistedClusterStateService.java:380)\n\tat [email protected]/org.elasticsearch.gateway.GatewayMetaState.start(GatewayMetaState.java:101)\n\tat [email protected]/org.elasticsearch.node.Node.start(Node.java:1294)\n\tat [email protected]/org.elasticsearch.bootstrap.Elasticsearch.start(Elasticsearch.java:436)\n\tat [email protected]/org.elasticsearch.bootstrap.Elasticsearch.initPhase3(Elasticsearch.java:229)\n\tat [email protected]/org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:67)\n"}

Steps to Reproduce

In order to reproduce you could create an index_template containing an alias

such as (... from the docs):

PUT _index_template/template_1
{
  "index_patterns": ["te*", "bar*"],
  "template": {
    "settings": {
      "number_of_shards": 1
    },
    "mappings": {
      "_source": {
        "enabled": true
      },
      "properties": {
        "host_name": {
          "type": "keyword"
        },
        "created_at": {
          "type": "date",
          "format": "EEE MMM dd HH:mm:ss Z yyyy"
        }
      }
    },
    "aliases": {
      "mydata": { }
    }
  },
  "priority": 500,
  "composed_of": ["component_template1", "runtime_component_template"], 
  "version": 3,
  "_meta": {
    "description": "my custom"
  }
}

and then if you create a index with the same name of the alias such as:

PUT /mydata

It will create correctly the index.

but then no operation is permitted on the index

Logs (if relevant)

No response

[salvob41]

well. I was just sperimenting with this.

And I realised that while this is true for v8.5.0, it does not allow me to create a index with the same template name in v8.5.2.

So I guess this is fixed in v8.5.2 :)

Thank you, in advance.

I could not find anything related to this kind of issue on the backlog :D

[DaveCTurner]

Yes this was fixed in 8.5.1 by #91456 - closing this as a duplicate.