What is LXD?

LXD is a next generation system container and virtual machine manager. It offers a unified user experience around full Linux systems running inside containers or virtual machines.

https://linuxcontainers.org/lxd/introduction/

  • it’s a container manager;
  • it allows you to run Linux Containers (LXC)
  • But it gives you additional features, such as clustering

Getting started with LXD Containerization (Full Guide!)

Installation on Ubuntu

sudo snap install lxd

For other distributions, see https://linuxcontainers.org/lxd/getting-started-cli/#installation

Initial Configuration

sudo lxd init

Storage backend to use

I’m not going to choose zfs in my case. That’s highly recommended if you can choose that or if you have the hardware to support that. I would actually need another dedicated drive in order to effectively manage zfs. So what I’m going to do instead is set it to directory or dir for to use a directory on the file system. Again, zfs is highly recommended, but it’s better to use zfs with a dedicated block device which I don’t currently have available.

List remote servers

lxc remote list

List images available from the server ‘images’

lxc image list images:

List images that have ‘debian’ in the name

lxc image list images: debian

Create Ubuntu image VM

lxc launch images:ubuntu/21.10/desktop ubuntu2110 --vm -c limits.cpu=4 -c limits.memory=4GiB --console=vga

--console=vga immediately get the video output once the instance is created.

--vm tells it’s a virtual machine. To create a container instead, run:

lxc launch images:ubuntu/21.10 ubuntu-21.10-container

If Ubuntu asks you for a password, then open a terminal on your host machine and set it with:
lxc exec ubuntu2110 -- passwd ubuntu

source: https://askubuntu.com/questions/932976/what-are-root-and-ubuntu-password-in-lxc-ubuntu16-04-container

Create Arch Linux

lxc launch images:archlinux/desktop-gnome archlinux --vm -c limits.cpu=4 -c limits.memory=4GiB -c security.secureboot=false --console=vga

Arch Linux is a bit different, because they don’t really have a default desktop environment, so as a result the variant there is called desktop-gnome.

The other difference with Arch Linux is that it is not signed with a valid secure boot key, which means we need to disable secure boot so that the VM can actually boot.

List containers and virtual machines

lxc list

+------------+---------+------+------+-----------------+-----------+
|    NAME    |  STATE  | IPV4 | IPV6 |      TYPE       | SNAPSHOTS |
+------------+---------+------+------+-----------------+-----------+
| archlinux  | STOPPED |      |      | VIRTUAL-MACHINE | 0         |
+------------+---------+------+------+-----------------+-----------+
| ubuntu2110 | STOPPED |      |      | VIRTUAL-MACHINE | 0         |
+------------+---------+------+------+-----------------+-----------+

List your local images

lxc image list local:

ALIAS FINGERPRINT PUBLIC DESCRIPTION ARCHITECTURE TYPE SIZE UPLOAD DATE
  71ba5f5629fe no Ubuntu impish amd64 (20210902_07:42) x86_64 VIRTUAL-MACHINE 1528.84MB Sep 3, 2021 at 11:42am (UTC)
  d4341a461a32 no Archlinux current amd64 (20210904_04:18) x86_64 VIRTUAL-MACHINE 1262.39MB Sep 4, 2021 at 2:15pm (UTC)

As you can see, by they default they don’t have an alias, so let’s create an alias for them!

Creating an alias for an existing image

lxc image alias create Description: Create aliases for existing images

Usage: lxc image alias create [:] [flags]

lxc image alias create local:ubuntu-21-10 71ba5f5629fe

You now can create containers/VM using this image!
No need to download gigabytes again …

Creating a VM (I thought it would create a container … :/) from a local image

$ lxc launch local:ubuntu-21-10 ubuntu-21-10-container
Creating ubuntu-21-10-container
Starting ubuntu-21-10-container

It has the same type as the base image …
It shows it as a Virtual Machine …

Execute a command in the running containter/VM

lxc exec instance-name -- apt install apache2

Get instance info

$ lxc info ubuntu2110
Name: ubuntu2110
Status: STOPPED
Type: virtual-machine
Architecture: x86_64
Created: 2021/09/03 11:42 UTC
Last Used: 2021/09/04 11:02 UTC

Start instance

lxc start instace-name

Stop instance

lxc stop instace-name

Access VM shell

lxc console ubuntu2110

Access VM GUI

lxc console ubuntu2110 --type=vga

How do I copy a file from host into a LXD container?

https://discuss.linuxcontainers.org/t/how-do-i-copy-a-file-from-host-into-a-lxd-container/2066

lxc file push myfile.txt mycontainer/home/ubuntu/

How do I copy a file/directory from host into a LXD container?

https://askubuntu.com/questions/1048217/how-do-i-copy-a-file-directory-from-host-into-a-lxd-container

# Suppose we want to copy file.txt from host to /home/ubuntu/ directory of the container1

lxc file push file.txt container1/home/ubuntu/

# to copy a directory from host to container, use -r

lxc file push -r direcoty/ vm1/home/ubuntu/

# to copy file from container to host, use pull

lxc file pull vm1/home/ubuntu/file.txt .

List Storages

$ lxc storage list

+---------+--------+--------------------------------------------+-------------+---------+
|  NAME   | DRIVER |                   SOURCE                   | DESCRIPTION | USED BY |
+---------+--------+--------------------------------------------+-------------+---------+
| default | zfs    | /var/snap/lxd/common/lxd/disks/default.img |             | 5       |
+---------+--------+--------------------------------------------+-------------+---------+

Describe storage

$ lxc storage show default

To start your first instance, try: lxc launch ubuntu:18.04

config:
  size: 20GB
  source: /var/snap/lxd/common/lxd/disks/default.img
  zfs.pool_name: default
description: ""
name: default
driver: zfs
used_by:
- /1.0/images/20512f15fed33bb25a83fd4ee9a6aa2fd72d8bb97c1d3323007580a1fee7c619
- /1.0/images/71ba5f5629fe4489309fb2948467976e3a1cfd1446e692c40709f4d9778ee741
- /1.0/instances/archlinux
- /1.0/instances/ubuntu2110
- /1.0/profiles/default
status: Created
locations:
- none

Create an snapshot

Snapshots are very useful if you want to try something out, maybe you want to install a piece of software, see how it affects the container and then if you don’t like the changes, roll that back as if nothing ever happened.

lxc snapshot instance-name snapshot-name

Delete snapshot

lxc delete instance-name/snapshot-name

Restore snapshot

lxc restore instance-name snapshot-name

Start the container automatically

lxc config set instance-name boot.autostart 1

Setting ceiling for memory

lxc config set instance-name limits.memory 1GB

Show container configuration

lxc config show instance-name

architecture: x86_64
config:
  image.architecture: amd64
  image.description: Ubuntu impish amd64 (20210902_07:42)
  image.os: Ubuntu
  image.release: impish
  image.serial: "20210902_07:42"
  image.type: disk-kvm.img
  image.variant: desktop
  limits.cpu: "4"
  limits.memory: 4GiB
  volatile.base_image: 71ba5f5629fe4489309fb2948467976e3a1cfd1446e692c40709f4d9778ee741
  volatile.eth0.hwaddr: 00:16:3e:b7:ef:f4
  volatile.last_state.power: STOPPED
  volatile.uuid: 5283dec6-3083-4999-b11b-1fd9bef3257b
  volatile.vsock_id: "4"
devices: {}
ephemeral: false
profiles:
- default
stateful: false
description: ""

TODO change storage location

By default it creates images in /var/snap/lxd/common/lxd/disks, but I don’t have much space in /, so I need to find out how to create the images in /home.

Maybe there’s info on how to do it here:
Storage configuration

Creating a new storage pool

LXD Change Storage Location

$ lxc storage create sdb1 btrfs source=/home/lesco/dev/lxd/sdb1

Error: Provided path does not reside on a btrfs filesystem

Storage pool vs Storage volume

From Simos Xenitellis - Storage volumes vs disk devices: questions:

A storage volume 26 is disk space that has been allocated from a storage pool, to be used by a container. Container images are also stored in storage volumes.

To list your storage pools, run the following. Here, there is a single storage pool which happens to be called lxd.

$ lxc storage list
NAME DESCRIPTION DRIVER SOURCE USED BY
lxd   zfs lxd 6

Let’s list the storage volumes in the storage pool. I have not created a separate storage volume, so we are seeing the volumes created by LXD for my containers, plus the storage volumes for any cached container images. There are two containers and three container images, in total five. I do not know why lxc storage list lxd shows six instead of five. Probably because when I sudo zfs list, I can see a deleted image so that may account for the sixth storage volume.

$ lxc storage volume list lxd
TYPE NAME DESCRIPTION USED BY
container c1   1
container c2   1
image 018d083aec1332a90bf9ae851c9790a17cfe51a2a83ed4a2d041956363a6aada   1
image 2e4d679ce33b8f1ec2ee4d82cd2a413093e978d037a84b3b30a11161f679d2fc   1
image 8f9da4cd832ba0235749caa2249c1ecfcee0cee052c4647fb502955fcec70072   1

But what are these container images? Can we easily see what those hashes correspond to? We do that with lxc image list. Indeed, the hashes correspond with the hashes of the storage volumes.

$ lxc image list
ALIAS FINGERPRINT PUBLIC DESCRIPTION ARCH SIZE UPLOAD DATE
openwrt-chaos_calmer-20181120-212658 2e4d679ce33b no openwrt 15.05.1 x86_64 (default) (20181120_21:26) x86_64 2.17MB Nov 20, 2018 at 7:29pm (UTC)
  018d083aec13 no ubuntu 16.04 LTS amd64 (release) (20181114) x86_64 158.12MB Nov 15, 2018 at 11:03pm (UTC)
  8f9da4cd832b no ubuntu 18.04 LTS amd64 (release) (20181101) x86_64 174.44MB Nov 13, 2018 at 12:19am (UTC)

In retrospect, a disk device 21 is disk space from the host filesystem that has been shared to a container.

TODO run a custom Linux kernel

Run ISO with LXD

Absolutely. For this you’d follow instructions similar to what I showed in the Windows 11 video.
Essentially:

  • lxc init some-name –vm -c limits.cpu=4 -c limits.memory=4GiB
  • lxc config device override some-name root size=50GiB
  • lxc config device add some-name install disk source=/path/to/the/iso/file boot.priority=10
  • lxc start some-name –console=vga

This creates a blank instance with 4 vCPU and 4GiB of RAM, grows its disk to 50GiB and then attaches a cdrom drive with your ISO. It then starts it with you attached to the VGA console so you can go through the install process.

References

Getting started with LXD Containerization (Full Guide!)

LXD Getting started - command line

Arch Linux and Ubuntu Desktop in LXD VMs

Running virtual machines with LXD 4.0

Container or Virtual Machine

LXD Change Storage Location

A little missundertanding for ‘lxd init’