Envoy: Allow dynamic cluster configuration for redis clusters

[dadadom]

Title: Feature Request: Allow redis cluster configuration via CDS

Description:
As mentioned in https://github.com/istio/istio/pull/1915, envoy currently does not allow to configure redis clusters via CDS. Trying to do so will result in a respective exception being thrown at https://github.com/envoyproxy/envoy/blob/master/source/common/config/utility.cc#L48

I would like to have the ability to configure redis cluster.

If that is not possible/planned, please add this limitation explicitly to the documentation.

[mattklein123]

It's possible, someone just needs to work on it. We can add a clear limitation for now to the docs. cc @danielhochman

[mattklein123]

@danielhochman I can fix this as a small work item in the next few days unless you are actively working on this. LMK.

[danielhochman]

@mattklein123 i was planning on updating the docs this week and scheduling the work later (need a little guidance on how to do it)

if you want to do it i'd be happy to code review, or if you want to tell me how to approach it and it's a small task i can do it next week.

[mattklein123]

@danielhochman you can do it, I will go over it with you.

[stale[bot]]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or other activity occurs. Thank you for your contributions.

[shuoli84]

Prevent close. still in radar, right? @mattklein123

[mattklein123]

Yes, the fix is not hard, someone just needs to do it.

[venilnoronha]

I'd like to work on this. @mattklein123 @rshriram if this is still available, could you assign it to me?