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

TL;DR

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. 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.

The error

'unsuccessful cred copy' permission-denied warning in Tasks

Fix

1. 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. Expected: You get the expected result; the problem is gone.

2. Re-run the original operation and confirm the error is gone. Expected: no error, normal output.

When to use

• You hit this exact error with Tekton.
• The symptom matches: 'unsuccessful cred copy' permission-denied warning in Tasks.

When NOT to use

• A different error message from Tekton; the cause here is specific to this error.
• Unrelated Tekton issues (different feature, different failure).
• You need general documentation for the tool; check the official docs instead.

Compatibility

Reported against Tekton. Source: https://github.com/tektoncd/pipeline/blob/main/docs/auth.md.

Variant phrasings

'unsuccessful cred copy' permission-denied warning in Tasks

Why it happens

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

Edge cases

• If your error message differs even slightly, this is probably a different issue; search the exact text.
• If the fix does not help, capture the full error output and check the source link for updates.

Source

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

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