# -p "*": Set crypted password to "*".  */!/!! indicate a password that can't be used to login.
# -U: Create a group with the same name as the user and make that this user's primary group.
# -G group_csv: Also add user to these supplementary groups.
# -m: Create home directory for this user.
sudo useradd -p "*" -U -m username -G sudo

# The docker systemd config is in the readonly system here.
cat /usr/lib/systemd/system/docker.service

# Copy to rw filesystem so we can edit it.
cp /usr/lib/systemd/system/docker.service /etc/systemd/system/

# Edit the ExecStart line to customize to your taste.
vim /etc/systemd/system/docker.service

mkdir -p /tmp/new-drive/openstack/latest
cp user_data /tmp/new-drive/openstack/latest/user_data
mkisofs -R -V config-2 -o configdrive.iso /tmp/new-drive
rm -r /tmp/new-drive