To configure a compute node to use Docker, there is a Docker driver that needs to be installed on the compute node to use as the compute Nova compute's driver. There are directions for how to do everything, which we will discuss in the documentation in the GitHub repository for the nova-docker driver at https://github.com/openstack/nova-docker.

The first task is to delete the virtual machines running. Once the following configuration is completed, OpenStack will not be able to manage the virtual machines running on the compute node. Go ahead and delete any running instances you have.

Next, let's walk through the setup instructions. Start by logging into a compute node, installing git, docker, and Docker Python support, cloning the nova-docker GitHub repository, and running setup.py to install the driver:

compute# yum install -y git docker python-docker-py
compute# systemctl enable docker
compute# git clone https://github.com/openstack/nova-docker
compute# cd nova-docker
compute# python setup.py install

Now that the nova-docker driver is installed, modify the configuration file /etc/nova/nova.conf. Update the compute_driver setting from the libvirt driver to the docker driver. The compute_driver parameter will be commented out. Add another line below it with the new value. That way, you know what the default value was and the new value will be active:

#compute_driver=libvirt.LibvirtDriver
compute_driver=novadocker.virt.docker.DockerDriver

For these changes to take effect, restart the Nova compute service. The docker driver will try to connect to the docker service, so start docker first:

compute# systemctl start docker
compute# systemctl restart openstack-nova-compute