Creating an Index-based Engine is broken on the GUI in app-search

[ndesanto (Nick)]

Hello!

When using Elasticsearch App Search we need to create index-based engines, but when we go to search for the index on GUI we encounter a 502 error. It seems to be because of the Index-searching box as it comes up with 0 results; whereas in our Prod environment this process works fine.

Some other notes:

• Using the API to create index-based engines works
• This problem persisted from our upgrade from ES 8.7.0 -> 8.18.1.
• my running theory is we have some corrupted index?

Here is a screenshot of what ES is displaying

Has anyone ran into this issue before/ have any advice on how to fix this?

Thanks!

edit: fixed version from 8.13.1 to 8.18.1

[Mark_Hoy (Mark J. Hoy)]

Hi @ndesanto -

A couple of questions

• This problem persisted from our upgrade from ES 8.7.0 -> 8.13.1.

Are you saying this problem occurred on 8.7 as well, and then you upgraded to 8.13.1, and it's still occurring?

Also - are your Elasticsearch instances running the same version as your Kibana instances and your Enterprise Search instances as well? (i.e. did you upgrade everything from 8.7 to 8.13.1, or only Elasticsearch?)

I have a feeling there might be a version mismatch somewhere, as the callout banner in your screenshot was not added until 8.16.

[ndesanto (Nick)]

Thanks Mark

Yes, the problem occurred on 8.7 before we upgraded and is still occurring on 8.18.1 after we upgrade (as you can tell by the banner in the screenshot)

We did the upgrade through the upgrade-assistant/elastic cloud so I believe everything is the same version:

Result of GET / in the dev tools console

{
  "name": "instance-0000000006",
  "cluster_name": "f00b58db2b534e819084ac8afc5cdb55",
  "cluster_uuid": "RbYwnIyGSbeFNjml4FMM3A",
  "version": {
    "number": "8.18.1",
    "build_flavor": "default",
    "build_type": "docker",
    "build_hash": "df116ec6455476a07daafc3ded80e2bb1a3385ed",
    "build_date": "2025-04-30T10:07:44.026929518Z",
    "build_snapshot": false,
    "lucene_version": "9.12.1",
    "minimum_wire_compatibility_version": "7.17.0",
    "minimum_index_compatibility_version": "7.0.0"
  },
  "tagline": "You Know, for Search"
}

Is there anywhere else I should check the version of?

edit: fixed version from 8.13.1 to 8.18.1

[Mark_Hoy (Mark J. Hoy)]

@ndesanto - thanks for the additional context - I did not realize that you were on an Elastic Cloud hosted environment... if you used the upgrade dialogues through that, then you should be on the same versions for all components...

• Using the API to create index-based engines works

You note that you were able to use the API to create an engine - were you able to successfully use the API to list the engines as well to list all engines (Engines API | App Search documentation [8.18] | Elastic) ?

If that fails, you can add in [the X-Enterprise-Search-Debug header] (Troubleshooting | App Search documentation [8.18] | Elastic) to get additional information about the query that App Search is sending to Elasticsearch which might help pinpoint the cause.

Since this appears to be a gateway error (502) - it might be a good case for opening a support case as well as we'd be able to then see your cluster's infrastructure and help diagnose this.

[ndesanto (Nick)]

Yep, getting all engines works; I believe its just a UI/internal API issue for internal/enterprise_search/search_indices

Also, I don't know why I keep typing v8.13.1, I mean our current version is v8.18.1; I'll edit my previous comments!

[Mark_Hoy (Mark J. Hoy)]

@ndesanto - Thanks for the additional note and correction on the versioning...

I would think that perhaps the next place to look would be in the Kibana logs for your cluster - that would most likely have a message regarding the 502 error, as well as more potential debugging information and messaging.

If this does not yield any good information, since you are on the Elastic Hosted Cloud - it might help to also open a support case so that our engineers would be able to help view your logs as well.