Best practice for mounting CephFS for both Proxmox storage and LXC bind mount


Active Member
Sep 19, 2017
I'm experimenting with Ceph Reef and Proxmox 8. Proxmox has made creating and configuring the new Ceph cluster really pleasant.

I intend to use CephFS both as a shared Proxmox storage (which was easy to add when creating the fs with the "add as storage" checkbox in the gui), and as a bind mount point for LXC containers (and perhaps someday pass to VMs via virtiofs).

Proxmox already makes available the filesystem by virtue of it being configured as storage at /mnt/pve/cephfs on each node. Is it a poor practice to utilize sub-directories off this mount point for shared storage passed to LXC containers via bind mount points? E.g. passing /mnt/pve/cephfs/shared_data into a LXC container while Proxmox creates and uses say /mnt/pve/cephfs/iso and/or /mtn/pve/cephfs/vztmpl.

Of course I could configure each node's fstab to mount a sub-directory of the already configured CephFS at say /mnt/bindmounts/shared_data and change the Proxmox storage to another sub-directory in the filesystem (rather than the root), but I would have to configure and manage each node individually for that, while the /mnt/pve mount point already "just works".

I do note the documentation states:
"For security reasons, bind mounts should only be established using source directories especially reserved for this purpose, e.g., a directory hierarchy under /mnt/bindmounts. Never bind mount system directories like /, /var or /etc into a container - this poses a great security risk."
However, I would be only using source directories below the /mnt/pve/cephfs mount point.

Even if doing it this way works, are there downsides I should consider here?


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