Add the following code to the manifest file:
class { 'docker':
tcp_bind => ['tcp://127.0.0.1:2375'],
socket_bind => 'unix:///var/run/docker.sock',
ip_forward => true,
iptables => true,
ip_masq => true,
bip => '192.168.1.1/24',
fixed_cidr => '192.168.1.144/28',
}
This should do!