We're currently on etcd 3.5.6, since then there has been at least another newer release.  This epic description is to track changes that we need to pay attention to:

Golang 1.17 update

In 3.5.7 etcd was moved to 1.17 to address some vulnerabilities:

https://github.com/etcd-io/etcd/blob/main/CHANGELOG/CHANGELOG-3.5.md#go

We need to update our definitions in the release repo to match this and test what impact it has.

EDIT: now moving onto 1.19 directly: https://github.com/etcd-io/etcd/pull/15337

WAL fix carry

3.5.6 had a nasty WAL bug that was hit by some customers, fixed with https://github.com/etcd-io/etcd/pull/15069

Due to the Golang upgrade we carried that patch through OCPBUGS-5458

When we upgrade we need to ensure the commits are properly handled and ordered with this carry.

IPv6 Formatting

There were some comparison issues with same IPv6 addresses having different formats. This was fixed in https://github.com/etcd-io/etcd/pull/15187 and we need to test what impact this has on our ipv6 based SKUs.

serializable memberlist 

This is a carry we have for some time: https://github.com/openshift/etcd/commit/26d7d842f6fb968e55fa5dbbd21bd6e4ea4ace50

This is now officially fixed (slightly different) with the options pattern in: https://github.com/etcd-io/etcd/pull/15261 

We need to drop the carry patch and take the upstream version when rebasing.