In this chapter, we have explored the integration of Docker into an OpenStack cluster. In a cluster that has multiple compute nodes, Docker instances and virtual machine instances can coexist with one another. Remember that they cannot co-exist on the same compute node. A single compute node is dedicated to either virtual machines or to Docker containers.

In Chapter 11, Scaling Horizontally, we will add a second compute node to re-enable your OpenStack deployment to have virtual machine capability. Once the new node is added, you will have the capability to run both Docker containers and virtual machines in your OpenStack cluster.