[LXC] Shared bind mount between two unprivileged containers not accessible

[Komagain]

Hi everyone,


I'm trying to share a directory containing Frigate clips between two LXC containers on Proxmox VE:

• CT 101 (Frigate): Unprivileged container writing video clips
• CT 102 (LPR service): Unprivileged container that should read those clips

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What I’ve done:​

On the Proxmox host, I:

1. Created a logical volume and mounted it:

lvcreate -V100G -T pve/data -n sharedclips
mkfs.ext4 /dev/pve/sharedclips
mkdir -p /mnt/frigate_share/clips
mount /dev/pve/sharedclips /mnt/frigate_share/clips

1. Set ownership and permissions:

chown 100000:100000 /mnt/frigate_share/clips
chmod 775 /mnt/frigate_share/clips

1. Added bind mount to both containers:

# /etc/pve/lxc/101.conf
lxc.mount.entry: /mnt/frigate_share/clips /media/frigate/clips none bind,create=dir


# /etc/pve/lxc/102.conf
lxc.mount.entry: /mnt/frigate_share/clips /mnt/frigate/clips none bind,create=dir

1. Confirmed /mnt/frigate_share/clips is not a symlink and accessible on host.
2. Restarted both containers after configuration (pct stop, pct start).

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Problem:​

• From inside container 102, /mnt/frigate/clips does not exist.
• Even after stopping, unmounting, and remounting the container with pct unmount and pct mount, no change.
• Tried checking findmnt, lsns, and verified that ownership matches UID/GID mapping (100000:100000).
• unprivileged=1 is set for both containers.

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Additional Info:​

• Host: Proxmox VE 8.x
• Containers: Debian 12 unprivileged
• subuid/subgid for root set to root:100000:65536
• No errors in journalctl -xe or pct start logs
• Host /mnt/frigate_share/clips/test.txt exists, but not visible in CT 102

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What I’m looking for:​

• Why is the bind mount not visible in CT 102?
• Is there anything else to check for unprivileged containers sharing the same bind mount?
• Should one of them be privileged for this setup to work?

Thanks in advance!