[Feature Request] Alias to include patterns for multiple remote clusters: `*:my-index`

[genedragon]

Is your feature request related to a problem? Please describe

When decomposing a very large cluster into several smaller manageable clusters, cross-cluster search allows index aliases to include remote-1:my-index and remote-2:* to search across multiple remote clusters.
Since we maintain same or similar index names across multiple clusters, we would like to create an index alias that includes multiple remote clusters such that uses don't have to worry about which destination cluster holds the data they are searching for.

Describe the solution you'd like

We would like to create index aliases in the form *:my-index, which would return results from any of the remote clusters which have my-index.

Related component

Search:Remote Search

Describe alternatives you've considered

No response

Additional context

No response

[rudrat0319]

@genedragon I'd like to work on this issue, can u pls assign it to me

[genedragon]

@rudrat0319 , Thanks for volunteering! Unfortunately, I don't have assignment permissions in this repo,

[sandeshkr419]

[Search Triage] @rudrat0319 Thanks for your interest, please let us know in case you need help diving in the code.

Something to help you proceed:

• ignore_unavailable=true flag, this should help you handle the missing index in clusters gracefully in case you decide to fan-out the search request to all clusters. Ref.