Multiple K8S clusters under one Elastic cluster

Hey Everyone,

Is it possible to have multiple K8S/OCP clusters with their own Elastic operators installed, but have Elasticsearch under the same cluster?

We're migrating from K8S to OCP and we need to migrate the cluster settings and data. I'm aware that we can backup and restore from shared storage/S3, etc. but that would be the less prefered option.

What we wanna do is simply join the nodes from OCP to the existing cluster, wait for the data to replicate, and shut down the old one.

Bumping this in hopes of getting a response

I do not use ECK, but it would be better if you provide more context about what you are trying to do, it is not clear what exactly you are trying to do.

What is OCP? Where are your current cluster running? On-premises?

If I undestand correctly what you are trying to do (effectively create, even if temporarily, an Elasticsearch cluster across K8s clusters) then that’s currently not possible or supported by ECK.

You would need to have all the pods routable across both k8s clusters, because the Elasticsearch nodes need to establish connections between every node in the Elasticsearch cluster.
Then you would need to establish trust between the nodes on the ES transport layer. ECK manages that trust by issuing certificates but is not aware of things outside the scope of the cluster its running in.
Finally ECK orchestration e.g. for managing the master nodes is also not aware of anything outside of the cluster the operator is installed in. With two operators in two clusters there is no clear ownership.

What you could try instead is to look into estalishing a remote cluster relationship between the two and either replicate the data through that or use reindex from remote.

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That is exactly what we want to do. As suspected, it will not work, we just wanted to make sure.

Yeah we can either set up CCR, or remote reindex (which is hella slow so that's a no-go), or just backup/restore which we will probably do.

Thanks for the help!