opencontainers / opencontainers/runc
can't start nginx image with runc and user namespaces (works with crun)
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- Dominant language
- Go
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Description
Description
Trying to start a Kubernetes container with userns using the nginx official image, fails. This was reported here: https://github.com/containerd/containerd/issues/10598 by @ctrox.
@ctrox also found a workaround: add "tty: true" to the kubernetes pod makes it work.
And a simpler repro: just a container with userns that runs "cat /dev/stderr" also fails with permission denied.
I guess you need to run detached (as containerd does) to hit this, otherwise it uses your shell and that probably works.
@ctrox thanks for the great bug report!
Sorry the brevity, I'm sick ATM. I'll add more info when I recover
Steps to reproduce the issue
No response
Describe the results you received and expected
Works, as without user namespaces.
What version of runc are you using?
runc 1.2.0
Host OS information
No response
Host kernel information
No response
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the nginx container failure with user namespaces under runc 1.2.0, then compare it with crun and the simpler detached cat /dev/stderr case. Check whether adding tty: true changes the result; done means the userns container starts without that workaround.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- go, kubernetes, linux, nginx
- Domain
- infrastructure, operating-systems, security
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 30/100