dragon9783 / lxd

Daemon based on liblxc offering a REST API to manage containers

LXD

REST API, command line tool and OpenStack integration plugin for LXC.

LXD is pronounced lex-dee.

To easily see what LXD is about, you can try it online.

CI status

• Travis:
• Jenkins:

Getting started with LXD

Since LXD development is happening at such a rapid pace, we only provide daily builds right now. They're available via:

sudo add-apt-repository ppa:ubuntu-lxc/lxd-git-master && sudo apt-get update
sudo apt-get install lxd

Because group membership is only applied at login, you then either need to close and re-open your user session or use the "newgrp lxd" command in the shell you're going to interact with lxd from.

newgrp lxd

After you've got LXD installed and a session with the right permissions, you can take your first steps.

Using the REST API

The LXD REST API can be used locally via unauthenticated Unix socket or remotely via SSL encapsulated TCP.

via Unix socket

curl --unix-socket /var/lib/lxd/unix.socket \
    -H "Content-Type: application/json" \
    -X POST \
    -d @hello-ubuntu.json \
    "https://127.0.0.1:8443/1.0/containers"

via TCP

TCP requires some additional configuration and is not enabled by default.

lxc config set core.https_address "[::]:8443"

curl -k -L -I \
    --cert ~/.config/lxc/client.crt \
    --key ~/.config/lxc/client.key \
    -H "Content-Type: application/json" \
    -X POST \
    -d @hello-ubuntu.json \
    "https://127.0.0.1:8443/1.0/containers"

JSON payload

The hello-ubuntu.json file referenced above could contain something like:

{
    "name":"some-ubuntu",
    "ephemeral":true,
    "config":{
        "limits.cpu":"2"
    },
    "source": {
        "type":"image",
        "mode":"pull",
        "protocol":"simplestreams",
        "server":"https://cloud-images.ubuntu.com/releases",
        "alias":"14.04"
    }
}

Building from source

We recommend having the latest versions of liblxc (>= 1.1 required) and CRIU (>= 1.7 recommended) available for LXD development. Additionally, LXD requires Golang 1.5 or later to work. All the right versions dependencies are available via the LXD PPA:

sudo apt-get install software-properties-common
sudo add-apt-repository ppa:ubuntu-lxc/lxd-git-master
sudo apt-get update
sudo apt-get install golang lxc lxc-dev mercurial git pkg-config protobuf-compiler golang-goprotobuf-dev xz-utils tar acl make

There are a few storage backends for LXD besides the default "directory" backend. Installing these tools adds a bit to initramfs and may slow down your host boot, but are needed if you'd like to use a particular backend:

sudo apt-get install lvm2 thin-provisioning-tools
sudo apt-get install btrfs-tools

To run the testsuite, you'll also need:

sudo apt-get install curl gettext jq sqlite3 uuid-runtime pyflakes pep8 shellcheck bzr

Building the tools

LXD consists of two binaries, a client called lxc and a server called lxd. These live in the source tree in the lxc/ and lxd/ dirs, respectively. To get the code, set up your go environment:

mkdir -p ~/go
export GOPATH=~/go

And then download it as usual:

go get github.com/lxc/lxd
cd $GOPATH/src/github.com/lxc/lxd
make

...which will give you two binaries in $GOPATH/bin, lxd the daemon binary, and lxc a command line client to that daemon.

Machine Setup

You'll need sub{u,g}ids for root, so that LXD can create the unprivileged containers:

echo "root:1000000:65536" | sudo tee -a /etc/subuid /etc/subgid

Now you can run the daemon (the --group sudo bit allows everyone in the sudo group to talk to LXD; you can create your own group if you want):

sudo -E $GOPATH/bin/lxd --group sudo

First steps

LXD has two parts, the daemon (the lxd binary), and the client (the lxc binary). Now that the daemon is all configured and running (either via the packaging or via the from-source instructions above), you can create a container:

$GOPATH/bin/lxc launch ubuntu:14.04

Alternatively, you can also use a remote LXD host as a source of images. One comes pre-configured in LXD, called "images" (images.linuxcontainers.org)

$GOPATH/bin/lxc launch images:centos/7/amd64 centos

Bug reports

Bug reports can be filed at https://github.com/lxc/lxd/issues/new

Contributing

Fixes and new features are greatly appreciated but please read our contributing guidelines first.

Contributions to this project should be sent as pull requests on github.

Hacking

Sometimes it is useful to view the raw response that LXD sends; you can do this by:

lxc config set core.trust_password foo
lxc remote add local 127.0.0.1:8443
wget --no-check-certificate https://127.0.0.1:8443/1.0 --certificate=$HOME/.config/lxc/client.crt --private-key=$HOME/.config/lxc/client.key -O - -q

Upgrading

The lxd and lxc (lxd-client) binaries should be upgraded at the same time with:

apt-get update
apt-get install lxd lxd-client

Support and discussions

We use the LXC mailing-lists for developer and user discussions, you can find and subscribe to those at: https://lists.linuxcontainers.org

If you prefer live discussions, some of us also hang out in #lxcontainers on irc.freenode.net.

FAQ

How to enable LXD server for remote access?

By default LXD server is not accessible from the networks as it only listens on a local unix socket. You can make LXD available from the network by specifying additional addresses to listen to. This is done with the core.https_address config variable.

To see the current server configuration, run:

lxc config show

To set the address to listen to, find out what addresses are available and use the config set command on the server:

ip addr
lxc config set core.https_address 192.168.1.15

When I do a lxc remote add over https, it asks for a password?

By default, LXD has no password for security reasons, so you can't do a remote add this way. In order to set a password, do:

lxc config set core.trust_password SECRET

on the host LXD is running on. This will set the remote password that you can then use to do lxc remote add.

You can also access the server without setting a password by copying the client certificate from .config/lxc/client.crt to the server and adding it with:

lxc config trust add client.crt

How do I configure alternative storage backends for LXD?

LXD supports various storage backends; below are instructions on how to configure some of them. By default, we use a simple directory backed storage mechanism, but we recommend using ZFS for best results.

ZFS

First, you need to install the ZFS tooling. On Wily and above this is just:

sudo apt-get install zfsutils-linux

ZFS has many different ways to procure a zpool, which is what you need to feed LXD. For example, if you have an extra block device laying around, you can just:

sudo zpool create lxd /dev/sdc6 -m none

However, if you want to test things out on a laptop or don't have an extra disk laying around, ZFS has its own loopback driver and can be used directly on a (sparse) file. To do this, first create the sparse file:

sudo truncate -s 100G /var/lib/lxd.img

then,

sudo zpool create lxd /var/lib/lxd.img -m none

Finally, whichever method you used to create your zpool, you need to tell LXD to use it:

lxc config set storage.zfs_pool_name lxd

BTRFS

The setup for btrfs is fairly simple, just mount /var/lib/lxd (or whatever your chosen LXD_DIR is) as a btrfs filesystem before you start LXD, and you're good to go. First install the btrfs userspace tools,

sudo apt-get install btrfs-tools

Now, you need to create a btrfs filesystem. If you don't have an extra disk laying around, you'll have to create your own loopback device manually:

sudo truncate -s 100G /var/lib/lxd.img
sudo losetup /dev/loop0 /var/lib/lxd.img

Once you've got a loopback device (or an actual device), you can create the btrfs filesystem and mount it:

sudo mkfs.btrfs /dev/loop0 # or your real device
sudo mount /dev/loop0 /var/lib/lxd

LVM

To set up LVM, the instructions are similar to the above. First, install the userspace tools:

sudo apt-get install lvm2 thin-provisioning-tools

Then, if you have a block device laying around:

sudo pvcreate /dev/sdc6
sudo vgcreate lxd /dev/sdc6
lxc config set storage.lvm_vg_name lxd

Alternatively, if you want to try it via a loopback device, there is a script provided in /scripts/lxd-setup-lvm-storage which will do it for you. It can be run via:

sudo apt-get install lvm2
./scripts/lxd-setup-lvm-storage -s 10G

And it has a --destroy argument to clean up the bits as well:

./scripts/lxd-setup-lvm-storage --destroy

How can I live migrate a container using LXD?

Live migration requires a tool installed on both hosts called CRIU, which is available in Ubuntu via:

sudo apt-get install criu

Then, launch your container with the following,

lxc launch ubuntu $somename
sleep 5s # let the container get to an interesting state
lxc move host1:$somename host2:$somename

And with luck you'll have migrated the container :). Migration is still in experimental stages and may not work for all workloads. Please report bugs on lxc-devel, and we can escalate to CRIU lists as necessary.

Can I bind mount my home directory in a container?

Yes. The easiest way to do that is using a privileged container:

1.a) create a container.

lxc launch ubuntu privilegedContainerName -c security.privileged=true

1.b) or, if your container already exists.

    lxc config set privilegedContainerName security.privileged true

2. then.

   lxc config device add privilegedContainerName shareName disk source=/home/$USER path=/home/ubuntu

How can I run docker inside a LXD container?

To run docker inside a lxd container, you must be running a kernel with cgroup namespaces (Ubuntu 4.4 kernel or newer, or upstream 4.6 or newer), and must apply the docker profile to your container.

lxc launch ubuntu:xenial my-docker-host -p default -p docker

Note that the docker profile does not provide a network interface, so the common case will want to compose the default and docker profiles.

The container must be using the Ubuntu 1.10.2-0ubuntu4 or newer docker package.