$ lxc config device override cbuild root size=40GB
# as per https://discuss.linuxcontainers.org/t/resize-containers-volume/4853 among others
Device root overridden for cbuild
but that doesn’t affect the size of the disk inside the container. The container is running Ubuntu 20.04 (according to lsb_release inside the container) and I’m fairly sure that I created it from the stock ubuntu images rather than anything weird. Seemingly this image doesn’t auto-resize its disks? Or perhaps it does and I’m doing this wrong. Anyway, I don’t understand what I need to do here to give the container more disk space. Do I need to change the size of the underlying storage? (Is this a “zpool”, whatever that is?) Or do I need to resize the partition from inside the image and then expand the zfs filesystem in it, as if this were a real disk that I’d just put more space on? I’m terribly confused.
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.
I have followed the instructions given and it does indeed seem to have worked; my container’s space is now larger! Thank you.
To confirm, this is what I did:
sudo apt install zfsutils-linux # to get the zfs command
zfs list -t all
# this lists loads of stuff, but "default" is at the top
# and shows the amount of space I had, which was 27GB
sudo ls /var/snap/lxd/common/lxd/disks/default.img
# this file exists, confirming that I have ZFS, it's using a loop file,
# it's called "default", and I'm using the snapped LXD
lxc stop cbuild # stop my LXD instance; unsure if this is required
sudo snap stop lxd # for non-snap this might be sudo service stop lxd?
# unsure if stopping lxd is required before fiddling with the ZFS stuff
sudo truncate -s +10G /var/lib/lxd/disks/default.img
# I wanted to add 10G of space because, as above, I told
# the container it had 40GB rather than the 30GB it had already
# for the below the docs say "lxd", not "default", as the pool name
# if you put the wrong name you get "cannot open 'lxd': no such pool"
sudo zpool set autoexpand=on default
sudo zpool online -e default /var/lib/lxd/disks/default.img
sudo zpool set autoexpand=off default
sudo snap start lxd # and restart lxd
lxc start cbuild # and my instance
sudo snap stop lxd # for non-snap this might be sudo service stop lxd?
# unsure if stopping lxd is required before fiddling with the ZFS stuff
sudo truncate -s +10G /var/lib/lxd/disks/default.img
# I wanted to add 10G of space because, as above, I told
# the container it had 40GB rather than the 30GB it had already
sudo snap start lxd # and restart lxd # <<< start the lxd again if not he will tell u no such pool too
# for the below the docs say "lxd", not "default", as the pool name
# if you put the wrong name you get "cannot open 'lxd': no such pool"
sudo zpool set autoexpand=on default
sudo zpool online -e default /var/lib/lxd/disks/default.img
sudo zpool set autoexpand=off default
# sudo snap start lxd # and restart lxd
