I spent months trying to get some clustering solution of redis running in kubernetes. Every single solution was a huge hack such as running a HAProxy in front on it and having that point to the master.
The best solution I found was running keydb in a multi-master, multi-replica mode. All of the pods are masters, any pod can be written to and the keys will be copied over to the other masters/replicas. Performance is decent too.
So I guess keydb is pretty solid in production? I considered it when running into problems with redis, but opted against it since none of my co-workers had any experience with it
So far it seems to be ok. My stack is 1 customer per namespace and I am running it across around 100+ namespaces, 3 keydb pods each. Some customers are very bursty - I don't have an RPS - but they are holding up for us.
I would still only do redis as a single non-persistent cache if it was up to me.