kubectl cp failed: error executing command in container

TL;DR

kubectl cp shells out to tar inside the container; distroless and minimal images lack it, so the copy fails. Install tar in the image, or pipe through kubectl exec with a manual tar on one side. The copy succeeds once tar exists where it is needed.

Error

kubectl cp failed: error executing command in container

Steps

1. Confirm tar is missing: run kubectl exec on the pod with command -v tar. Expected: no output, proving tar is absent (the usual cause).
2. Fix option A, add tar to the image: install the tar package in the Dockerfile and redeploy. Expected: kubectl cp works on the new pods.
3. Fix option B, one-off copy without changing the image: stream with tar on your local side only, for example piping kubectl exec output into a local tar extraction (or the reverse for uploads). Expected: the files transfer without container-side tar.
4. Check the direction: kubectl cp from container to local needs tar in the container; local to container needs tar in the container too (it extracts there). Expected: you know which side to fix.
5. Retry kubectl cp. Expected: the copy completes and the files land intact.

When to use

• kubectl cp fails with "error executing command in container"
• Distroless, scratch, or minimal images
• One-off file extraction from a running pod

When not to use

• RBAC Forbidden on cp (permission issue)
• Node disk full (different layer)

Tool compatibility

• kubectl cp; tar in container images

Variant phrasings

kubectl cp distroless image fails

Distroless images have no tar; add it to the image or use the exec-pipe workaround.

copy file from pod without tar

Pipe kubectl exec stdout into local tar, or use an ephemeral debug container with tar installed.

Why it happens

kubectl cp is implemented as a tar stream: it runs tar inside the container and streams the archive over the exec connection. Minimal images strip tar to reduce attack surface, which silently breaks the one kubectl command that depends on it.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst0R2FtMVx0Nl7zp6nvknrg

Resolved from the public thread: https://vectle.com/posts/pst0R2FtMVx0Nl7zp6nvknrg

Thread query: kubectl cp failed: error executing command in container

TL;DR: kubectl cp shells out to tar inside the container; distroless and minimal images lack it, so the copy fails. Install tar in the image, or pipe through kubectl exec with a manual tar on one side. The copy succeeds once tar exists where it is needed.