HOWTO get started with lxc and lxdThu, Apr 23, 2015
Today Ubuntu released 15.04 (Vivid Vervet) which is a huge release for the lastest cloud and server options. Updated OpenStack, Juju, libvirt, qemu, Open vSwitch, Ceph, cloud-init, docker, corosync, haproxy, pacemaker - and the stars of the show, Ubuntu’s take on the container world, lxc, lxd and Ubuntu Core, aka Snappy. With all of that fun stuff I didn’t waste any time, I grabbed the server ISO of 15.04 and slapped it on a server. I got started with lxc and lxd to check them out, and while there’s plenty more to do and learn, here’s how to get started with them.
LXD (pronounced lex-dee I’ve heard) is the Daemon based on liblxc offering a REST API to manage containers, specifically the LXC containers. To learn more, checkout Linux Containers is the umbrella project behind LXC, LXD, LXCFS and CGManager. So, let’s get started, shall we?
Install the software
Everything is in the repos, so if you’re in 15.04 you should be good to go. Let’s begin
apt-get update apt-get install lxd lxd-client lxc lxc-templates python-lxc lua-lxc snappy system-image-snappy-cli
Boom, we’re ready!
Start me up
Start LXD to get the game going
service lxd start
Prepare your user
This kind of setup seems to be something they’ll automate later and have the installer handle, but until then, let’s check some things. Your user should have a uid and gid map defined in
/etc/subgid. The default should be 65536 for both the uids and gids, so you should be all set in Ubuntu - but if not, use usermod to set your user correctly. then, in `/etc/lxc/lxc-usernet (which is used to set network devices quota for unprivileged users) add a line like this:
your-username veth lxcbr0 10
This just means that “your-username” can create up to 10 veth devices to connect to the lxcbr0 bridge.
Launch some containers
So enough of this, let’s run some instnances. If you checkout Linux Containers you can learn about container names you can download and use, but for now we’ll just use the basic ones.
- Debian 8 (Jessie)
$ sudo lxd-images import lxc debian jessie amd64 --alias debian --alias debian/jessie Downloading the GPG key for https://images.linuxcontainers.org Downloading the image list for https://images.linuxcontainers.org Validating the GPG signature of /tmp/tmpel_rn4fq/index.json.asc Downloading the image: https://images.linuxcontainers.org/images/debian/jessie/amd64/default/20150421_22:42/lxd.tar.xz Validating the GPG signature of /tmp/tmpel_rn4fq/debian-jessie-amd64-default-20150421_22:42.tar.xz.asc Image imported as: 7bd9061a169dd5171469034963d1cf683550d28f8706b3a69a0715944e527984 Setup alias: debian Setup alias: debian/jessie
- Ubuntu 15.04 (Vivid)
$ sudo lxd-images import lxc ubuntu vivid amd64 --alias ubuntu --alias ubuntu/vivid sudo lxd-images import lxc ubuntu vivid amd64 --alias ubuntu --alias ubuntu/vivid Downloading the GPG key for https://images.linuxcontainers.org Downloading the image list for https://images.linuxcontainers.org Validating the GPG signature of /tmp/tmphymwwli8/index.json.asc Downloading the image: https://images.linuxcontainers.org/images/ubuntu/vivid/amd64/default/20150422_03:49/lxd.tar.xz Validating the GPG signature of /tmp/tmphymwwli8/ubuntu-vivid-amd64-default-20150422_03:49.tar.xz.asc Image imported as: 98ea382481a29de263d5657ed076893047c8917249ce01ad3b1f4c1f21e341b5 Setup alias: ubuntu Setup alias: ubuntu/vivid
Easy cheesy, right? Let’s take a look and see what lxc sees running:
$ sudo lxc list +------------------------+---------+-----------+------+-----------+ | NAME | STATE | IPV4 | IPV6 | EPHEMERAL | +------------------------+---------+-----------+------+-----------+ | trafficless-garfield | RUNNING | 10.0.3.38 | | NO | | nondiphtherial-shawana | RUNNING | | | NO | +------------------------+---------+-----------+------+-----------+
Not bad, while I don’t see all of the aliases I added, we clearly see two running!
Again, I’m just getting started with this, it seems very promising. There’s obviously tons more to do, here are some of them. Once I do I’ll update this post, but feel free to add what you know in the comments, or as a pull request. Remember, we’re all in this together kid!
- Creating unprivileged containers as root
- Entering a container, starting some services we can see from outside of the container
- Run a system-wide unprivileged container (an unprivileged container started by root) (note that root doesn’t need network devices quota, instead using the global configuration file)
- Network containers together (something lacking in Docker, out of the box at least)
- Checkout orchestration options (same comment about Docker here)
- Run Snappy, see what can be done with it
- and more, I’m sure, stay tuned!