Add a second disk image to a LXC container in Proxmox 4

lxcproxmox

My LXC containers in Proxmox 4 have a root filesystem stored on the host as a RAW disk image stored in :

/var/lib/vz/images/<ct_id>/vm-<ct-id>-disk-1.raw

This folder on the host computer is from an ext4 partition :

/dev/mapper/pve-data on /var/lib/vz type ext4 (rw,relatime,data=ordered)

I would like to attach a second disk image to a LXC container, but I can't find any way of achieving that. All I've managed to do was to bind-mount a folder from my host system to the container, but that's not an option for what I want to do : add a storage volume to my OpenMediaVault container.

Do you know any way (using Proxmox UI or/and CLI) of attaching a second disk image to a LXC container ?

Thanks.

Best Answer

See in below example how I mount an LVM partition from the host inside the guest machine:

execute these steps on the host machine. The number 100 is the id of the guest machine:

vi /var/lib/lxc/100/fstab
/dev/vg0/vm-100-disk-2 var/lib/mysql ext4 noatime 0 0

enable guest based fstab entry:

vi /var/lib/lxc/100/config
lxc.mount = /var/lib/lxc/100/fstab

Related Solutions

How to migrate a regular LXC container to a Proxmox LXC container

Without detailed explanation here is how you can do this.

Create an archive of your LXC container.
Create a Proxmox Container using that archive as a template.

First cd into your lxc container root directory:

cd /var/lib/lxc/debian8/rootfs/

(If you used an lvm volume as your containers storage, you need to mount it and cd into your mount point, which can be done by mount /dev/mapper/<lvgroup-lvdisk> /var/lib/lxc/debian8/rootfs/, and than cd into the mount point)

Create an archive:

tar -czvf /var/lib/vz/template/cache/my_debian8_template.tar.gz ./

Then create a new proxmox container out of that

pct create 100 /var/lib/vz/template/cache/my_debian8_template.tar.gz \
    -description LXC -hostname pvecontainer01 -memory 1024 -nameserver 8.8.8.8 \
    -net0 name=eth0,hwaddr=52:4A:5E:26:58:D8,ip=192.168.15.147/24,gw=192.168.15.1,bridge=vmbr0 \
    -storage local -password changeme

(You can modify your options as you would like.)

For more information see - man pct

Proxmox: recreate CT from “.raw” disk image

First, backup what you have. Ideally all nodes and all VM/CT data.

Then, recover a cluster to where it is stable. Determine the cause of your last data loss. Crash it and be sure it comes back. fsck file systems to be sure data survives.

Now you can rebuild. The .raw should contain a filesystem, which yes you can use again. At least you can mount it as is and try to recover data.

Regarding the .conf files, those are on Proxmox's replicated database backed file system. See Proxmox Cluster file system (pmxcfs) to read more about pmxcfs. In particular, you might be able to stop pve-cluster on a node with the same name, replace config.db, and reboot.

There is not a lot to the .conf though, it contains the options for when you set up the container. Rebuilding the config is always an option. Then stop the CT and replace the .raw with what you have. Note the IP or MAC on the network interface may be different if you didn't recover the previous addresses.

Although, the web UI doesn't seem to allow editing the disk. If you need to change the path or size, use a text editor on the .conf.