[SOLVED] LXC container not cloning when mp mounts present

[kyriazis]

Hello,

I am trying to clone a container that has a mp0 mount point, but I'm getting an error "unable to clone mount point 'mp0' (type bind) (500)".

Of course I can remove the mount, clone, and then re-add it, but it gets cumbersome after a while.

Any particular reason why it is not allowed to clone the mounpoint to the new container? Is that going to be fixed in the (near) future?

Running PVE 6.4-5.

Thank you!

george

 

[oguz]

hi,

but I'm getting an error "unable to clone mount point 'mp0' (type bind) (500)".

that error message means your mountpoint is a bind mount. [0]

since a bindmount exposes an arbitrary directory from your host, if we included those when cloning a container, it would clone also those files that are mounted -- every time. so if you had a big NFS share mounted from your host, all those files would be needlessly copied and it could take a lot of time

[0]: https://pve.proxmox.com/wiki/Linux_Container#_bind_mount_points

 

[kyriazis]

Bind mounts, however, are not backed up, which seems like an inconsistency to me. Why they would behave one way during a backup and a different way during a clone?

Is there a way to create a mount point in such a way that a CT clone will clone the mount point and not the contents?

Thank you!

George

 

[oguz]

Bind mounts, however, are not backed up, which seems like an inconsistency to me. Why they would behave one way during a backup and a different way during a clone?

they're not included in neither backups nor clones.
if i make a backup of the container with bindmount i'll get:

INFO: starting new backup job: vzdump 103
INFO: filesystem type on dumpdir is 'zfs' -using /var/tmp/vzdumptmp939380_103 for temporary files
INFO: Starting Backup of VM 103 (lxc)
INFO: Backup started at 2021-06-09 16:12:18
INFO: status = running
INFO: CT Name: deb
INFO: including mount point rootfs ('/') in backup
INFO: excluding bind mount point mp0 ('/test') from backup (not a volume)
...
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: create storage snapshot 'vzdump'
INFO: creating vzdump archive '/var/lib/vz/dump/vzdump-lxc-103-2021_06_09-16_16_15.tar'
INFO: Total bytes written: 822118400 (785MiB, 128MiB/s)
INFO: archive file size: 784MB
INFO: removing backup 'local:backup/vzdump-lxc-103-2020_07_07-16_41_35.tar'
INFO: cleanup temporary 'vzdump' snapshot
INFO: Finished Backup of VM 103 (00:00:08)
INFO: Backup finished at 2021-06-09 16:16:23
INFO: Backup job finished successfully

see the line that mentions it was excluded.

Is there a way to create a mount point in such a way that a CT clone will clone the mount point and not the contents?

you mean you still want to keep the mp0 line in your configuration or?

if you do a backup/restore instead of clone, then this line will be kept in the configuration

$ pct restore 10104 /var/lib/vz/dump/vzdump-lxc-103-2021_06_09-16_16_15.tar
...
restoring '/var/lib/vz/dump/vzdump-lxc-103-2021_06_09-16_16_15.tar' now..
extracting archive '/var/lib/vz/dump/vzdump-lxc-103-2021_06_09-16_16_15.tar'
Total bytes read: 822118400 (785MiB, 241MiB/s)
Detected container architecture: amd64
merging backed-up and given configuration..

$ pct config 10104
arch: amd64
cores: 1
hostname: deb
memory: 512
mp0: /home/oguz/test,mp=/test,size=0T
nameserver: 1.1.1.1 8.8.8.8
net0: name=eth0,bridge=vmbr0,firewall=1,hwaddr=2E:37:D8:89:F1:AB,ip=dhcp,type=veth
ostype: debian
rootfs: local:10104/vm-10104-disk-0.raw,size=8G
swap: 512
unprivileged: 1

and you can see the mp0 line in the config of the new container.

hope this helps!

 

[kyriazis]

Thank you, that works!

George