The document provides an overview of Linux Containers (LXC) and their manager LXD, detailing installation, configuration, and management commands for container creation, snapshots, and resource control. LXC allows multiple isolated Linux systems to run on a single kernel, while LXD simplifies management with a virtual machine-like user experience. Specific command-line examples are included for various operations such as creating, starting, and stopping containers.

1. Linux Containers
LXC
Open Source Camp Moldova 2018

2. $ whoami
Vladimir Melnic
Developer
DevOps
https://github.com/vmelnic
https://fb.com/melnic.vladimir
2

3. $ man lxc
LXC (Linux Containers) is an operating-system-level virtualization method for
running multiple isolated Linux systems (containers) on a control host using a
single Linux kernel. https://en.wikipedia.org/wiki/LXC
LGPL-2.1
C 88.9% Shell 7.4% M4 2.5% Other 1.2%
Initial release: August 6, 2008
Stable release: 3.0.0, 28 May 2018
3

4. $ man lxd
LXD is a next generation system container manager. It offers an user experience
similar to virtual machines but using Linux containers instead.
https://linuxcontainers.org/lxd/introduction/
Apache-2.0
Go 91.0%, Shell 7.9%, Other 1.1%
Stable release: 3.0.0, 3 Apr 2018
4

5. Features
● cgroups - CPU, memory, block I/O, network, etc.
● namespaces - Process IDs, hostnames, user IDs, file names etc.
● unprivileged containers
● snapshot
● migrations
● LXD - Rest API
● LXCFS - Userspace (FUSE) filesystem
https://linuxcontainers.org/lxcfs/introduction/
5

6. Install
# Ubuntu:
$ sudo apt install lxd lxd-client
# Centos/RHEL 7:
$ sudo yum install yum-plugin-copr epel-release
$ sudo yum copr enable ngompa/snapcore-el7
$ sudo yum install snapd
$ sudo snap install lxd
https://discuss.linuxcontainers.org/t/lxd-on-centos-7/1250
6

7. Configure
$ sudo lxd init
> Do you want to configure a new storage pool (yes/no) [default=yes]? yes
> Name of the storage backend to use (dir or zfs) [default=dir]: dir
> Would you like LXD to be available over the network (yes/no) [default=no]? yes
> Address to bind LXD to (not including port) [default=all]: all
> Port to bind LXD to [default=8443]: 8443
> Trust password for new clients: *
> Again: *
> Do you want to configure the LXD bridge (yes/no) [default=yes]? yes
7

8. Configuring - network 1/11
8

9. Configuring - network 2/11
9

10. Configuring - network 3/11
10

11. Configuring - network 4/11
11

12. Configuring - network 5/11
12

13. Configuring - network 6/11
13

14. Configuring - network 7/11
14

15. Configuring - network 8/11
15

16. Configuring - network 9/11
16

17. Configuring - network 10/11
17

18. Configuring - network 11/11
18

19. $ sudo lxd init
> Do you want to configure a new storage pool (yes/no) [default=yes]?yes
> Name of the storage backend to use (dir or zfs) [default=dir]:dir
> Would you like LXD to be available over the network (yes/no) [default=no]?yes
> Address to bind LXD to (not including port) [default=all]:all
> Port to bind LXD to [default=8443]: 8443
> Trust password for new clients: *
> Again: *
> Do you want to configure the LXD bridge (yes/no) [default=yes]?yes
> LXD has been successfully configured.
$
19

20. Creating and starting
# Creating a container without starting it:
$ sudo lxc init ubuntu:16.04 <container>
# Creating and starting a new container:
$ sudo lxc launch ubuntu:16.04 <container>
https://linuxcontainers.org/lxd/getting-started-cli/
20

21. 21

22. List containers
$ sudo lxc list
22

23. 23

24. Start, stop and restart containers
# Start container:
$ sudo lxc start <container>
# Stop container:
$ sudo lxc stop <container>
# Restart container:
$ sudo lxc restart <container>
24

25. 25

26. Delete containers
$ sudo lxc delete <container>
26

27. 27

28. Exec
# Get a shell inside container:
$ sudo lxc exec <container> -- /bin/bash
# Run command inside container:
$ sudo lxc exec <container> -- apt-get upgrade -y
28

29. 29

30. 30

31. Images 1/2
# Built-in image remotes:
● ubuntu: (for stable Ubuntu images)
● ubuntu-daily: (for daily Ubuntu images)
● images: (for a bunch of other distros)
# Start a container from image:
$ sudo lxc launch ubuntu:14.04 my-ubuntu
$ sudo lxc launch ubuntu-daily:16.04 my-ubuntu-dev
$ sudo lxc launch images:centos/6/amd64 my-centos
31

32. Images 2/2
# Using a remote LXD as an image server:
$ sudo lxc remote add my-images 1.2.3.4
$ sudo lxc launch my-images:image-name your-container
32

33. List images
# Local images:
$ sudo lxc image list
# Built-in image remotes:
$ sudo lxc image list ubuntu:
$ sudo lxc image list ubuntu-daily:
$ sudo lxc image list images:
https://stgraber.org/2016/03/30/lxd-2-0-image-management-512
33

34. 34

35. 35

36. Container info
# Getting detailed information from a container:
$ sudo lxc info <container>
36

37. 37

38. Snapshot management
# Creating a snapshot:
$ sudo lxc snapshot <container> <snapshot>
# Listing snapshots:
$ sudo lxc info <container>
# Restoring a snapshot:
$ sudo lxc restore <container> <snapshot>
# Creating a new container from a snapshot:
$ sudo lxc copy <source container>/<snapshot> <destination container>
# Deleting a snapshot:
$ sudo lxc delete <container>/<snapshot>
38

39. 39

40. 40

41. Cloning and renaming
# Copying a container:
$ sudo lxc copy <source container> <destination container>
# Moving a container:
$ sudo lxc move <old name> <new name>
41

42. 42

43. 43

44. Resource control
● Disk (only for ZFS or btrfs storage backend)
● CPU
● Memory
● Network I/O (only supported for “bridged” and “p2p” type interfaces)
● Block I/O
https://stgraber.org/2016/03/26/lxd-2-0-resource-control-412
44

45. Applying some limits
# Container-wide limits:
$ sudo lxc config set <container> <key> <value>
# Profile:
$ sudo lxc profile set <profile> <key> <value>
# Device-specific:
$ sudo lxc config device set <container> <device> <key> <value>
45

46. CPU
# Limit a container to 1 CPU:
$ sudo lxc config set c1 limits.cpu 1
46

47. 47

48. Memory
# Limit a container memory (RAM) to 256 MB:
$ sudo lxc config set c1 limits.memory 256MB
48

49. 49

50. Questions?
50