relatedImages entry not populated in generated CSV when using Kustomize patches

[ricardozanini]

Bug Report

What did you do?

While generating the Operator bundle using operator-sdk (v1.35.0) with Kustomize and RELATED_IMAGE_* environment variables set, I noticed that the generated ClusterServiceVersion (CSV) does not correctly resolve and populate the relatedImages section unless I hardcode the image value directly in the manifest patch.

This behavior breaks the expected design, where:

• A Kustomize patch uses a variable such as ${RELATED_IMAGE_KUBE_RBAC_PROXY}.
• The environment variable is set prior to running the SDK commands.
• The Operator SDK should substitute that variable and automatically populate the relatedImages block accordingly in the generated bundle/manifests/*.clusterserviceversion.yaml.

However, unless the image is hardcoded in the patch file, the relatedImages array in the CSV is either missing or incomplete. This makes the usage of environment-variable-driven workflows brittle and defeats the purpose of using Kustomize + envs for reproducible builds.

Reproduction Steps:

1. Define a patch with ${RELATED_IMAGE_KUBE_RBAC_PROXY} in your Kustomize overlay (manager_auth_proxy_patch.yaml).

2. Set the env var before running:

   export RELATED_IMAGE_KUBE_RBAC_PROXY=gcr.io/kubebuilder/kube-rbac-proxy:v0.13.1

3. Run:

   operator-sdk generate kustomize manifests
   kustomize build config/manifests | operator-sdk generate bundle --package=<your-package>

4. Check the generated CSV under bundle/manifests/*.clusterserviceversion.yaml.

Additional context:

The CSV does correctly reference the env var inside the env array (e.g., value: ${RELATED_IMAGE_KUBE_RBAC_PROXY}), but the image field itself does not seem to get substituted during CSV generation for relatedImages.

What did you expect to see?

The relatedImages section should include:

relatedImages:
  - name: kube-rbac-proxy
    image: gcr.io/kubebuilder/kube-rbac-proxy:v0.13.1

What did you see instead? Under which circumstances?

relatedImages is either empty or not populated unless the image is hardcoded. So if I have:

containers:
  - name: kube-rbac-proxy
    image: ${RELATED_IMAGE_KUBE_RBAC_PROXY}
    env:
    - name: RELATED_IMAGE_KUBE_RBAC_PROXY
      value: ${RELATED_IMAGE_KUBE_RBAC_PROXY}

The spec.relatedImages field will have something like:

relatedImages:
  - name: kube-rbac-proxy
    image: ${RELATED_IMAGE_KUBE_RBAC_PROXY}

How can we use variable substitution in this scenario?

Environment

• Operator SDK version: v1.35.0
• Kustomize used via: operator-sdk generate kustomize manifests
• Image reference format: ${RELATED_IMAGE_KUBE_RBAC_PROXY} inside patch YAML

Operator type:

/language go

Kubernetes cluster type:

OpenShift

$ operator-sdk version
operator-sdk version: "v1.35.0", commit: "e95abdbd5ccb7ca0fd586e0c6f578e491b0a025b", kubernetes version: "1.28.0", go version: "go1.21.11", GOOS: "darwin", GOARCH: "arm64"

$ go version (if language is Go)

$ kubectl version

Possible Solution

Additional context