Hello,
I am looking into using elasticsearch federated cluster model to split data between multiple clusters and query them via federated cluster for a holistic view. One thing that is not clear and I am not able to find answers for in docs is "How do we perform upgrades to the clusters when operating federated cluster?"
Will the current version of client (in any language) will work with the newer version of elasticsearch as we rolling upgrade each cluster under federated cluster ? or every new version of elasticsearch server is backwards compatible with atleast it's previous version of client ?
Any pointers on how the upgrades works on gotchas to know before heading down this path will be helpful.
Thanks