500 Internal Server Error on parallel image pushes to GHCR #187118

shehbazk · 2026-02-14T03:28:09Z

shehbazk
Feb 14, 2026

Select Topic Area

Bug

Body

500 Internal Server Error when pushing images concurrently to GHCR

Summary

GitHub Container Registry (GHCR) intermittently returns 500 Internal Server Error responses when pushing container images concurrently. The error appears only when multiple docker push commands are executed in parallel from the same client. Switching to sequential/synchronous pushes eliminates the errors entirely.

Problem Description

When pushing multiple Docker images or tags to GHCR in parallel (via threading/multiprocessing), some push operations fail with:

received unexpected HTTP status: 500 Internal Server Error

The Docker CLI returns exit code 1, with empty stdout and the above error in stderr.

Key observation: Changing from concurrent to sequential pushes completely resolves the issue, suggesting GHCR has difficulty handling simultaneous push requests from the same client/authentication context.

Environment

Registry: GitHub Container Registry (ghcr.io)
Client tooling: Docker CLI (via python-on-whales wrapper)
Execution environment: Bitbucket Pipelines (managed runners)
Python version: 3.12.11
Push orchestration: ThreadPool with 4 workers executing parallel docker image push commands

Observed Behavior

Concurrent Push (Fails)

# python-on-whales code using ThreadPool
def _push_multiple_tags(
    self,
    tags_or_repos: List[str],
    quiet: bool,
    stream_logs: bool,
) -> Optional[Iterable[Tuple[str, bytes]]]:
    if stream_logs:
        return self._push_multiple_tags_stream(
            tags_or_repos=tags_or_repos,
            quiet=quiet,
            stream_logs=stream_logs,
        )
    else:
        pool = ThreadPool(4)  # 4 concurrent workers
        pool.starmap(
            func=self._push_single_tag,
            iterable=(
                (tags_or_repo, quiet, stream_logs) for tags_or_repo in tags_or_repos
            ),
        )
        pool.close()
        pool.join()
        return None

Result: Intermittent 500 errors on one or more push operations

Sequential Push (Works)

Loop over images and call docker push one at a time.

Result: No errors, all pushes succeed

Full Error Traceback

python_on_whales.exceptions.DockerException: The command executed was `/usr/bin/docker image push --quiet ghcr.io/org-name/some-app:v100`.
It returned with code 1
The content of stdout is ''
The content of stderr is 'received unexpected HTTP status: 500 Internal Server Error
'

Traceback (most recent call last):
  File "/opt/atlassian/pipelines/agent/build/cicd/src/ci/orchestration/tasks/executor.py", line 202, in _execute_stage
    result = self._execute(
             ^^^^^^^^^^^^^^
  File "/opt/atlassian/pipelines/agent/build/cicd/src/ci/orchestration/tasks/executor.py", line 119, in _execute
    result = executor.run(
             ^^^^^^^^^^^^^
  File "/opt/atlassian/pipelines/agent/build/cicd/src/ci/tasks/gradle.py", line 395, in run
    return process_built_docker_image_for_publishing(self._logger, task_input, image)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/atlassian/pipelines/agent/build/cicd/src/ci/tasks/docker.py", line 162, in process_built_docker_image_for_publishing
    push_image(logger, docker, image)
  File "/opt/atlassian/pipelines/agent/build/cicd/src/ci/tasks/docker.py", line 100, in push_image
    client.push(tags, quiet=True)
  File "/opt/atlassian/pipelines/agent/build/cicd/.venv/lib/python3.12/site-packages/python_on_whales/components/image/cli_wrapper.py", line 714, in push
    return self._push_multiple_tags(
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/atlassian/pipelines/agent/build/cicd/.venv/lib/python3.12/site-packages/python_on_whales/components/image/cli_wrapper.py", line 734, in _push_multiple_tags
    pool.starmap(
  File "/home/ubuntu/.local/share/uv/python/cpython-3.12.11-linux-x86_64-gnu/lib/python3.12/multiprocessing/pool.py", line 375, in starmap
    return self._map_async(func, iterable, starmapstar, chunksize).get()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/ubuntu/.local/share/uv/python/cpython-3.12.11-linux-x86_64-gnu/lib/python3.12/multiprocessing/pool.py", line 774, in get
    raise self._value
  File "/home/ubuntu/.local/share/uv/python/cpython-3.12.11-linux-x86_64-gnu/lib/python3.12/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
                    ^^^^^^^^^^^^^^^^^^^
  File "/home/ubuntu/.local/share/uv/python/cpython-3.12.11-linux-x86_64-gnu/lib/python3.12/multiprocessing/pool.py", line 51, in starmapstar
    return list(itertools.starmap(args[0], args[1]))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/atlassian/pipelines/agent/build/cicd/.venv/lib/python3.12/site-packages/python_on_whales/components/image/cli_wrapper.py", line 792, in _push_single_tag
    run(full_cmd, capture_stdout=quiet, capture_stderr=quiet)
  File "/opt/atlassian/pipelines/agent/build/cicd/.venv/lib/python3.12/site-packages/python_on_whales/utils.py", line 220, in run
    raise DockerException(
python_on_whales.exceptions.DockerException: The command executed was `/usr/bin/docker image push --quiet ghcr.io/org-name/some-app:v100`.
It returned with code 1
The content of stdout is ''
The content of stderr is 'received unexpected HTTP status: 500 Internal Server Error
'

Reproduction Steps

Authenticate to GHCR using a GitHub token
Build and tag multiple Docker images for pushing to GHCR (e.g., 3-5 images with different tags)
Execute docker push commands concurrently using threading/multiprocessing (ThreadPool with 4 workers)
Observe intermittent 500 Internal Server Error responses

To verify it's a concurrency issue:
5. Change the same code to push images sequentially (one at a time in a loop)
6. Observe that all pushes now succeed without errors

Questions

Is this behavior (HTTP 500 during concurrent pushes) expected under certain concurrency or rate conditions?
Is there a known limitation or recommended concurrency threshold for GHCR pushes from a single client?
3.If concurrent pushes are rate-limited or constrained, would it be possible to return a more specific HTTP status (for example, 429 Too Many Requests with retry guidance) instead of a generic 500 Internal Server Error? That would help us implement proper backoff strategies on our side.

Additional Debug Information Available

We can provide upon request:

Exact UTC timestamps of failures
Docker daemon logs from the client
Full docker --debug output for failed pushes
Request/response headers
CI/CD job IDs for correlation
Network packet captures if needed

Current Workaround

Push images sequentially instead of concurrently. This is slower but reliable until the server-side issue is resolved.

# Instead of ThreadPool, loop sequentially:
for tag in tags_or_repos:
    docker.push(tag, quiet=True)

2026-02-14T03:28:32Z

github-actions[bot]
bot Feb 14, 2026

💬 Your Product Feedback Has Been Submitted 🎉

Thank you for taking the time to share your insights with us! Your feedback is invaluable as we build a better GitHub experience for all our users.

Here's what you can expect moving forward ⏩

Your input will be carefully reviewed and cataloged by members of our product teams.
- Due to the high volume of submissions, we may not always be able to provide individual responses.
- Rest assured, your feedback will help chart our course for product improvements.
Other users may engage with your post, sharing their own perspectives or experiences.
GitHub staff may reach out for further clarification or insight.
- We may 'Answer' your discussion if there is a current solution, workaround, or roadmap/changelog post related to the feedback.

Where to look to see what's shipping 👀

Read the Changelog for real-time updates on the latest GitHub features, enhancements, and calls for feedback.
Explore our Product Roadmap, which details upcoming major releases and initiatives.

What you can do in the meantime 💻

Upvote and comment on other user feedback Discussions that resonate with you.
Add more information at any point! Useful details include: use cases, relevant labels, desired outcomes, and any accompanying screenshots.

As a member of the GitHub community, your participation is essential. While we can't promise that every suggestion will be implemented, we want to emphasize that your feedback is instrumental in guiding our decisions and priorities.

Thank you once again for your contribution to making GitHub even better! We're grateful for your ongoing support and collaboration in shaping the future of our platform. ⭐

0 replies

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

GitHub Community

500 Internal Server Error on parallel image pushes to GHCR #187118

Uh oh!

{{title}}

Uh oh!

Uh oh!

{{editor}}'s edit

{{editor}}'s edit

Uh oh!

Replies: 1 comment

Uh oh!

{{title}}

Uh oh!

Select a reply

Uh oh!

GitHub Community

500 Internal Server Error on parallel image pushes to GHCR #187118

Uh oh!

Uh oh!

shehbazk Feb 14, 2026

Select Topic Area

Body

500 Internal Server Error when pushing images concurrently to GHCR

Summary

Problem Description

Environment

Observed Behavior

Concurrent Push (Fails)

Sequential Push (Works)

Full Error Traceback

Reproduction Steps

Questions

Additional Debug Information Available

Current Workaround

Replies: 1 comment

Uh oh!

github-actions[bot] bot Feb 14, 2026

shehbazk
Feb 14, 2026

github-actions[bot]
bot Feb 14, 2026