skypilot-org/skypilot

[RunPod] FUSE mount fails inside Docker container - /dev/fuse: operation not permitted

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#8592 opened on Jan 15, 2026

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Description

Environment

  • SkyPilot version: 0.11.1
  • Cloud provider: RunPod
  • Container runtime: Docker (RunPod default)

Description

When launching a SkyPilot job on RunPod using a Docker image, the setup script fails to mount JuiceFS inside the container due to missing FUSE device permissions.

Error Logs

(setup pid=3732) 2026/01/15 04:39:08.698391 juicefs[5320] : The mount point is not ready in 10 seconds (mount process is not started yet), please check the log (/var/log/juicefs.log) or re-mount in foreground [checkMountpoint@mount_unix.go:249]

Dig into /var/log/juicefs.log, show following error logs:

2026/01/15 04:02:15.348704 juicefs[5420] : setpriority: permission denied [Serve@fuse.go:454] 2026/01/15 04:02:15.348968 juicefs[5420] : mknod /dev/fuse: operation not permitted [ensureFuseDev@device_linux.go:35] /usr/bin/fusermount: fuse device not found, try 'modprobe fuse' first 2026-01-15 04:02:15.352109 I | mount: fusermount exited with code 256 2026/01/15 04:02:15.352167 juicefs[5420] : fuse: fuse: fusermount exited with code 256 [mountMain@mount_unix.go:1056]

Expected Behavior

JuiceFS should mount successfully inside the Docker container. The same docker image and task yaml file works on AWS instances.

Workaround Attempts

  • Installing fuse package in Dockerfile - Doesn't help, as the issue is runtime permissions, not missing binaries
  • Using --privileged in docker run options - Still fails due to missing device and capabilities

Contributor guide

Tech stack
pythondocker
Domain
cloudinfrastructure
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Basic Docker knowledgeUnderstanding of Linux capabilities
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35
Research direction
Investigate why /dev/fuse is not available inside RunPod's Docker containers. Check if RunPod's container runtime uses a security profile that blocks FUSE or if device cgroup rules prevent access. Look at SkyPilot's setup scripts (likely in `setup.py` or `sky/clouds/runpod.py`) to see how they handle Docker mounts. Consider adding a comment to ask maintainers if they have logs from a successful mount on other cloud providers for comparison.