Expand LXC container filesystem

[trevor (Trevor Sullivan)]

I can’t figure out how to resize an LXC container filesystem. I’ve already overridden the default block storage device size, but I can’t “see” the block storage device inside the container.

# zfs get all default/containers/mycontainer
default/containers/mycontainer     used                  12.7G
default/containers/mycontainer     referenced            13.0G
default/containers/mycontainer     quota                 30G

How do I get the filesystem on the ZFS device to “fill” the 30GB of space?

I tried using cfdisk inside the container, and it doesn’t “see” the filesystem. lsblk doesn’t show the filesystem.

I already set autoexpand on, for the default ZFS pool, so that shouldn’t be an issue. I’m just trying to resize this one container disk.

[Manishfoodtechs]

Extend of elasticity in LXC Containers?

If you use a storage pool driver that doesn’t enforce storage quotas by default (dir, btrfs and zfs) and don’t use limits.* settings on the instance, then the instance can grow to use all of the storage of that pool and as much memory as the system has AFAIK.

[tomp (Thomas Parrott)]

You use

lxc config device (set|override) (instance) root size=nGiB

[trevor (Trevor Sullivan)]

@tomp

You use

Yes, I already know how to resize the block device. However, I can’t figure out how to expand the filesystem inside the container, after resizing the block device. Any thoughts?

[trevor (Trevor Sullivan)]

I figured it out. Finally found another thread with a similar issue.

It’s not clear from any documentation, but you have to run the truncate command to arbitrarily increase the zpool image size. Then you have to stop and restart LXD, so it “sees” the new ZFS pool size.

Resizing zfs filesystem in LXD container

Aha, ok. I assume I run this on the host? That zfs command seems to be in both zfsutils-linux and zfs-fuse; which one should I be using? $ zfs list -t all Command 'zfs' not found, but can be installed with: sudo apt install zfsutils-linux # version 0.8.3-1ubuntu12.1, or sudo apt install zfs-fuse # version 0.7.0-20 Normally I’d choose the most recent version, but it seems weird to me that they’re different packages, so I don’t want to be using the wrong thing.

My container filesystem appears larger now, inside the container.

[tomp (Thomas Parrott)]

Since that post you can also just do

lxc storage set (pool)  size=