Webhook mount location is incompatible with older versions of OLM

[njhale]

Bug Report

What did you do?

Attempt to deploy an operator with webhooks generated by SDK v1.1.0 against the release-4.6 version of OLM.

What did you expect to see?

The operator falls back to the old default serving cert mount locations for the release-4.6 version of OLM if the newer locations aren't populated:

older release-4.6 locations:

• /apiserver.local.config/certificates/apiserver.crt
• /apiserver.local.config/certificates/apiserver.key

newer master locations:

• /tmp/k8s-webhook-server/serving-certs/tls.cert
• /tmp/k8s-webhook-server/serving-certs/tls.key

What did you see instead? Under which circumstances?

The operator attempted to use only the new, unpopulated, serving cert mount locations and failed to be deployed:

$ kubectl get events -n operators

55s         Warning   Failed                pod/opentelemetry-operator-controller-manager-9bdd9fcc4-ctr8k     Error: cannot find volume "apiservice-cert" to mount into container "kube-rbac-proxy"
55s         Warning   Failed                pod/opentelemetry-operator-controller-manager-9bdd9fcc4-ctr8k     Error: cannot find volume "apiservice-cert" to mount into container "manager"

Environment

Operator type:

/language go

Kubernetes cluster type:

OpenShift

$ operator-sdk version

v1.1.0

Possible Solution

• Fall back to older default mount locations when current locations aren't populated
• Document OLM compatibility

Additional context

• A patch has been introduced into OLM that mounts serving certs in both the old and new locations. This will not be backported to 4.6 or any earlier releases since it would amount to supporting forwards compatibility with SDK.
• Original Issue
• Issue: documenting SDK/OLM compatibility

[varshaprasad96]

+1. We may have to document the OLM compatibility in general. Also for this specific issue, we could point out that for previous versions of OLM, the workaround is to specify the location of certs while setting up webhook with controller-runtime manager (ex: here).

[estroz]

/kind documentation
/assign