LXD Ubuntu VM launch and disk resize

launch_vm.sh

#!/bin/env bash

set -e

readonly VM="banana"
readonly CPU="8"
readonly MEM="8GB"
readonly DSK="120GB"

lxc init images:ubuntu/focal ${VM} -p default -p vm --vm
lxc config set ${VM} limits.cpu ${CPU}
lxc config set ${VM} limits.memory ${MEM}
lxc config device override ${VM} root size=${DISK}
lxc start ${VM}

sleep 10  # `lxc start` needs a `--wait`.

lxc exec ${VM} -- apt update
lxc exec ${VM} -- apt install cloud-initramfs-growroot -y
lxc exec ${VM} -- growpart /dev/sda 2
lxc exec ${VM} -- resize2fs /dev/sda2

vm-lxd-profile.yaml

config:
  user.user-data: |
    apt_mirror: http://us.archive.ubuntu.com/ubuntu/
    ssh_pwauth: yes
    users:
      - name: ubuntu
        passwd: "\$6\$s.wXDkoGmU5md\$d.vxMQSvtcs1I7wUG4SLgUhmarY7BR.5lusJq1D9U9EnHK2LJx18x90ipsg0g3Jcomfp0EoGAZYfgvT22qGFl/"
        lock_passwd: false
        groups: lxd
        shell: /bin/bash
        sudo: ALL=(ALL) NOPASSWD:ALL

    growpart:
      mode: auto
      devices:
        - '/'
        - '/dev/sda'
        - '/dev/sda2'
      ignore_growroot_disabled: false
description: VN profile
devices:
  config:
    source: cloud-init:config
    type: disk
  eth0:
    nictype: bridged
    parent: lxdbr0
    type: nic
  root:
    path: /
    pool: default
    size: 100GB
    type: disk
name: vm

Thought I'd add a little info for those that haven't created or edited new LXD Profiles before.

Using the above ".sh" and ".yaml" contents...

First, set your EDITOR environment to whatever text editor you use (vi, nano etc)

$ export EDITOR=nano

To add a new "profile" to LXD you can Create a new empty profile:

$ lxc profile create myprofile (note: you don't have to call the new profile "myprofile")

then edit the new myprofile

$ lxc profile edit myprofile

Note: there will be 5-6 default lines at the bottom... you can delete those then
"Copy & Paste" the text content from the vm-lxd-profile.yaml above to the new profile.

Save the file & quit your text editor.

You can see if LXD knows about your new "profile" by...

$ lxc profile list
+---------------+--------------------------+-----------------+
| NAME | DESCRIPTION | USED BY |
+---------------+--------------------------+-----------------+
| myprofile | VN profile | 1 |
+---------------+--------------------------+-----------------+
| default | Default LXD profile | 2 |
+---------------+--------------------------+----------------+

Finally, edit your copy of "launch_vm.sh" in the following Line:

$ lxc init images:ubuntu/focal ${VM} -p default -p vm --vm

and change the " -p vm " above to whatever you called your new LXD Profile

lxc init images:ubuntu/focal ${VM} -p default -p myprofile --vm

then run the script "launch_vm.sh"

$ chmod +x ./launch_vm.sh
$ ./launch_vm.sh

when its done you can see your new VM using:

$ lxc list

For further reference: LXD Profiles

Great stuff! Wish this was better documented on the LXD docs

Agreed. I spent all morning looking for this!

I do have one question though. I changed the user from "ubuntu" to "tux" because that's my preferred generic user, but tux isn't created but there is still an ubuntu user. Any suggestions?

For newer LXD versions (5.8 and LTS 5.0.2) you can use the -d flag to increase the disk size of LXD virtual machines:

lxc launch "images:ubuntu/jammy/cloud" jammy --vm -c limits.cpu=4 -c limits.memory=8GiB -d root,size=50GiB

I tested this with version 5.0.2-838e1b2 👍

See also:

• https://discuss.linuxcontainers.org/t/lxd-5-8-has-been-released/15686#device-override-on-init-and-launch-4
• https://discuss.linuxcontainers.org/t/lxd-vm-how-to-set-disk-size/7566/6

When I try to apply the above mentioned profile sudo lxc launch images:ubuntu/22.04 w1 -p myprofile the commands inside user.user-data do not get applied. My custom limits like cpus and RAM is respected but root size and installing packages defined within user.user-data do not work. I am using lxd 5.10. Do you guys have any experience with this kind of error?