Comment by trenchpilgrim

You can do leader election without etcd. The thing etcd buys you is you can have clusters of 3, 5, 7 or 9 DB nodes and lose up to 1, 2, 3, or 4 nodes respectively. But honestly, the vast majority of k8s users would be fine with a single SQL instance backing each k8s cluster and just running two or more k8s clusters for HA.

k3s doesn't require etcd, I'm pretty sure GKE uses Spanner and Azure uses Cosmos under the hood.