Linux Containers (LXC)

Linux Containers (LXC) @Open Source Camp Moldova 2018

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

1. Linux Containers
LXC
Open Source Camp Moldova 2018

2. $ whoami

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

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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

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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

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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/
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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
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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

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8. Configuring - network 1/11
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9. Configuring - network 2/11

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10. Configuring - network 3/11
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11. Configuring - network 4/11
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12. Configuring - network 5/11
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13. Configuring - network 6/11
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14. Configuring - network 7/11
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15. Configuring - network 8/11
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16. Configuring - network 9/11
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17. Configuring - network 10/11
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18. Configuring - network 11/11
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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.
$
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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/
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22. List containers


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

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26. Delete containers


$ sudo lxc delete <container>
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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
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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


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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

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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
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36. Container info

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

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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>
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46. CPU

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

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