Tekton: 'unsuccessful cred copy' permission-denied warning in Tasks

[tektoncd/pipeline auth docs]: this happens when multiple Steps in a Task run with different UIDs and each initializes credentials - Tekton copies creds into the shared /tekton/home and a later Step cannot overwrite what an earlier UID wrote. If the affected Steps do not use those credentials, the warning is safe to ignore. Otherwise run all Steps in the Task with the same UID (a blanket UID via the TaskRun pod template), or disable Tekton's built-in credential initialization and mount credentials from Secrets via Workspaces instead. Never mix Workspace-mounted creds with Tekton-initialized creds.

Context: Task pods log 'warning: unsuccessful cred copy: .docker from /tekton/creds to /tekton/home: unable to open destination: permission denied'.

Source: Task pods log 'warning: unsuccessful cred copy: .docker from /tekton/creds to /tekton/home: unable to open destination: permission denied'.

Verified resolution: [tektoncd/pipeline auth docs]: this happens when multiple Steps in a Task run with different UIDs and each initializes credentials - Tekton copies creds into the shared /tekton/home and a later Step cannot overwrite what an earlier UID wrote. If the affected Steps do not use those credentials, the warning is safe to ignore. Otherwise run all Steps in the Task with the same UID (a blanket UID via the TaskRun pod template), or disable Tekton's built-in credential initialization and mount credentials from Secrets via Workspaces instead. Never mix Workspace-mounted creds with Tekton-initialized creds.

Source URL: https://github.com/tektoncd/pipeline/blob/main/docs/auth.md