Please note that the instructions in this tutorial have been written for Ubuntu 16.04 Xenial Xerus. Your mileage may vary on other platforms. In particular, if you’re on Fedora, you’ll be unable to run unprivileged LXC containers (as of February 2018), as explained in this issue.

Command cheat sheet

This is for linux.conf.au 2018 attendees. It is not a complete list of commands you'll be using in the tutorial, just some of the more complex ones that you might want to copy and paste.

Prepare lxc-usernet

sudo tee -a /etc/lxc/lxc-usernet <<EOF
$USER veth lxcbr0 100
EOF

Install a container named xenial-sass

lxc-create -n xenial-sass -t ubuntu-cloud -- \
  --release=xenial \
  --tarball=https://cloud-images.ubuntu.com/xenial/current/xenial-server-cloudimg-amd64-root.tar.xz

lxc-start -n xenial-sass
lxc-attach -n xenial-sass

apt update
apt install ruby-sass ruby-listen

Enable user subuid and subgid mapping

for f in /etc/sub{u,g}id; do
  sudo tee -a $f <<EOF
$USER:100000:65535
EOF
done

Enable /home sharing

vi ~/.local/share/lxc/xenial-sass/config

lxc.mount.entry = /home home none rbind

# Ubuntu 16.04 / 17.04
lxc.id_map = u 0 100000 1000
lxc.id_map = g 0 100000 1000
lxc.id_map = u 1000 1000 1
lxc.id_map = g 1000 1000 1
lxc.id_map = u 1001 101001 64535
lxc.id_map = g 1001 101001 64535

# Ubuntu 17.10
lxc.idmap = u 0 100000 1000
lxc.idmap = g 0 100000 1000
lxc.idmap = u 1000 1000 1
lxc.idmap = g 1000 1000 1
lxc.idmap = u 1001 101001 64535
lxc.idmap = g 1001 101001 64535

lxc-stop -n xenial-sass
lxc-start -n xenial-sass

Get ansible-laptop-config

git clone https://github.com/fghaas/ansible-laptop
git clone https://github.com/fghaas/ansible-laptop-config-example
ansible-laptop-config

wget -O ansible-laptop-config/lxc_inventory.py \
  https://github.com/ansible/ansible/blob/devel/contrib/inventory/lxc_inventory.py

Run ansible against localhost

cd ansible-laptop
ansible-playbook -i ../ansible-laptop-inventory/inventory local.yml

Run ansible against containers

ansible -i ../ansible-laptop-inventory/lxc_inventory.py \
        -m raw \
        -a "apt-get --yes install python"

ansible-playbook -i ../ansible-laptop-inventory/lxc_inventory.py \
                 -t lxc local.yml