Conair - systemd OS containers

• Build Archlinux nspawn containers easily.
• Run other container orchestration tools inside of containers within a second. Much faster than using vagrant.
• Manage multiple services inside of a container without the hassle of supervisord.

Dependencies

• archlinux/CoreOS
• systemd-nspawn
• systemd-networkd (systemd 215+)
• systemd-machined (systemd 219+)
• (btrfs)

Build

Install go and run make. This will install conair to /usr/local/bin:

make && make install

If you don't have a btrfs partition/root then you can create a loopback device with btrfs and mount it to /var/lib/machines. I wrote a little tool called loopback for it.

sudo loopback create --name=conair --size=10 /var/lib/machines

Usage

Initialize your environment with:

conair init

Most of the times conair requires root privileges. So make sure to prepend sudo.

Create a base image:

conair bootstrap base # if you are on archlinux (pacstrap required)
conair pull base     # download an image

Or DIY:

btrfs subvolume create /var/lib/machines/base
pacstrap -i -c -d /var/lib/machines/base base

Build an image

Dockerfiles and Conairfiles are supported. FROM, RUN and ADD are implemented. Conairfiles support PKG and ENABLE to install pacman packages and enable systemd units.

conair build my-new-image

Commands

conair init      # Setup a bridge for the containers and add some iptables forwarding
conair destroy   # Remove bridge, iptables and unit file
conair images    # List all available conair images
conair run       # Run a container
conair ps        # List all conair containers
conair start     # Start a container
conair stop      # Stop a container
conair status    # Status of container
conair attach    # Attach to container
conair commit    # Commit a container
conair rm        # Remove a container
conair rmi       # Remove an image
conair pull      # Pull an image
conair bootstrap # Creates an arch rootfs with pacstrap.
conair help      # Show a list of commands or help for one command
conair version   # Print the version and exit

Why?

• Testing different docker versions inside of containers
• Having a nice workflow to create new nspawn containers
• A proper systemd integration between host and containers
• No need to use supervisord if you need to run multiple services within the same container
• All CoreOS components in a single container but change them independently and test quickly
• Systemd
• Fleet
• Etcd
• Docker