There was a flaky failure case where renaming a TLS hostname for an
ingress might leave the old hostname dangling in tailscaled config. This
happened when the proxygroup reconciler loop had an outdated resource
version of the config Secret in its cache after the
ingress-pg-reconciler loop had very recently written it to delete the
old hostname. As the proxygroup reconciler then did a patch, there was
no conflict and it reinstated the old hostname.
This commit updates the patch to an update operation so that if the
resource version is out of date it will fail with an optimistic lock
error. It also checks for equality to reduce the likelihood that we make
the update API call in the first place, because most of the time the
proxygroup reconciler is not even making an update to the Secret in the
case that the hostname has changed.
Updates tailscale/corp#24795
Change-Id: Ie23a97440063976c9a8475d24ab18253e1f89050
Signed-off-by: Tom Proctor <tomhjp@users.noreply.github.com>
8d84720edb