K8s pull from harbor ErrImagePull: x509: certificate signed by unknown authority

Question

When attempting to create a pod in a Kubernetes cluster that utilizes containerd as the container runtime and pulls an image from a Harbor registry, an ErrImagePull error occurs. The error message indicates a TLS certificate verification problem:

Events:
  Type     Reason     Age                From               Message
  ----     ------     ----               ----               -------
  Normal   Scheduled  27s                default-scheduler  Successfully assigned test-namespace-10/test-release-30-private-chart-7cd67d9597-bw4lg to node2
  Normal   BackOff    24s (x2 over 25s)  kubelet            Back-off pulling image "harbor-private.local/private/my-httpd:0.1.0" 
  Warning  Failed     24s (x2 over 25s)  kubelet            Error: ImagePullBackOff
  Normal   Pulling    11s (x2 over 26s)  kubelet            Pulling image "harbor-private.local/private/my-httpd:0.1.0" 
  Warning  Failed     11s (x2 over 26s)  kubelet            Failed to pull image "harbor-private.local/private/my-httpd:0.1.0": failed to pull and unpack image "harbor-private.local/private/my-httpd:0.1.0": failed to resolve reference "harbor-private.local/private/my-httpd:0.1.0": failed to do request: Head "https://harbor-private.local/v2/private/my-httpd/manifests/0.1.0": x509: certificate signed by unknown authority
  Warning  Failed     11s (x2 over 26s)  kubelet            Error: ErrImagePull

Resolution Attempts:

• Setting CONTAINERD_INSECURE_REGISTRIES environment variable to skip SSL verification: URL: https://github.com/kubernetes-sigs/kubespray/issues/9716
• Skip SSL Certificate Verification in containerd Configuration: In the containerd configuration file (/etc/containerd/config.toml), I try explicitly skipping SSL certificate verification by configuring the registry endpoint with the insecure option.
  URL: https://docs.daocloud.io/en/kangaroo/best-practice/insecure_registry/#new-method
• Modify Kubernetes Pod Spec to Skip SSL Verification: I try modifying the pod specification in Kubernetes to skip SSL verification explicitly: URL:Getting "x509: certificate signed by unknown authority" even with "--insecure-skip-tls-verify" option in Kubernetes

Any insights or suggestions for troubleshooting would be greatly appreciated.

Thank you!