Public bug reported: Rclone container fails to mount a FUSE filesystem inside Docker on Ubuntu 25.04 with a "fusermount3: mount failed: Permission denied" error, even when the container is run in privileged mode. Disabling AppArmor on the host resolves the issue.
After upgrading Ubuntu to 25.04, a Docker container using Rclone to mount a remote as a FUSE filesystem is consistently failing with a permission denied error related to fusermount3. Extensive troubleshooting, including ensuring correct host mount point permissions, verifying /dev/fuse access, and running the container with privileged: true, did not resolve the issue. The problem is resolved when AppArmor is completely disabled on the host system via kernel boot parameters, indicating a conflict between AppArmor, Docker, and FUSE on this Ubuntu release. The full bug info, including reproduction steps and other config, etc, is available here: https://gemini.google.com/share/f21b2572d06c Note: I asked Gemini to compose the bug report after having gone through all the testing options extensively; though it is mostly accurate, the few mistakes are because of its own hallucinations (e.g. calling Ubuntu 25.04 "Oracular Oriole" instead of "Plucky Puffin", etc ProblemType: Bug DistroRelease: Ubuntu 25.04 Package: fuse 3.14.0-10 ProcVersionSignature: Ubuntu 6.14.0-15.15-generic 6.14.0 Uname: Linux 6.14.0-15-generic x86_64 ApportVersion: 2.32.0-0ubuntu5 Architecture: amd64 CasperMD5CheckResult: pass Date: Fri May 16 13:47:38 2025 InstallationDate: Installed on 2024-10-09 (219 days ago) InstallationMedia: Ubuntu-Server 24.04.1 LTS "Noble Numbat" - Release amd64 (20240827) PackageArchitecture: all ProcEnviron: LANG=C.UTF-8 PATH=(custom, no user) SHELL=/bin/bash TERM=xterm XDG_RUNTIME_DIR=<set> SourcePackage: fuse3 UpgradeStatus: Upgraded to plucky on 2025-05-16 (0 days ago) ** Affects: fuse3 (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug plucky -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2111105 Title: Docker FUSE Mount Permission Denied on Ubuntu 25.04 with AppArmor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/fuse3/+bug/2111105/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
