[CI] TokenBackwardsCompatibilityIT.testGeneratingTokensInOldCluster failing on 7.x

[ywelsch]

This test has been repeatedly failing for the past two weeks

Build scan: https://gradle-enterprise.elastic.co/s/dqls7xeilan64

Output:

org.elasticsearch.upgrades.IndexingIT > testIndexing FAILED
02:48:18     org.elasticsearch.client.WarningFailureException: method [PUT], host [http://127.0.0.1:46683], URI [/test_index], status line [HTTP/1.1 200 OK]
02:48:18     Warnings: [index [test_index] matches multiple legacy templates [global, xpack-prevent-bwc-deprecation-template], composable templates will only match a single template]
02:48:18     {"acknowledged":true,"shards_acknowledged":true,"index":"test_index"}
02:48:18         at __randomizedtesting.SeedInfo.seed([CBB013D90C975055:2F6A5CD02AE213DE]:0)
02:48:18         at org.elasticsearch.client.RestClient.convertResponse(RestClient.java:289)
02:48:18         at org.elasticsearch.client.RestClient.performRequest(RestClient.java:263)
02:48:18         at org.elasticsearch.client.RestClient.performRequest(RestClient.java:237)
02:48:18         at org.elasticsearch.upgrades.IndexingIT.testIndexing(IndexingIT.java:77)

The problem seems to be related to the introduction of component templates, where a warning is now emitted due to the existing templates that are used in the system.

Marking this as both Security and Core/Features as I'm not sure which one is more applicable here.

[elasticmachine]

Pinging @elastic/es-security (:Security/Security)

[elasticmachine]

Pinging @elastic/es-core-features (:Core/Features/Features)

[ywangd]

I wonder whether this can be fixed in a similar way as #56028
Can someone who understand default_shards feature and/or composable templates please take a look?

[dakrone]

I believe this is a duplicate of #58258. I will take a look.

[cbuescher]

I think this failure from today looks related: https://gradle-enterprise.elastic.co/s/7nqywhqy2fu7s