I recently saw the Openstack self-healing demo from CoreOS team using Tectonic(Stackanetes project) and I kind of felt that the boundary between Containers and VMs are blurring. In this blog, I discuss the usecase of deploying Openstack using Containers.
We typically think of Openstack as a VM Orchestration tool. Openstack is composed of numerous services and deploying Openstack as one monolithic blob is pretty complex and difficult to maintain. The demo described showed how Containers simplify Openstack deployment. This is a great example of using Microservices architecture to simplify infrastructure deployment.
Following diagram shows the Openstack deployment model using Containers. The diagram below shows how Openstack service containers deploys user VM. The user VMs deployed using Openstack can run Containers as well..
Following are some notes on the architecture:
- Openstack services like Nova, Heat, Horizon are containerized using Openstack Kolla project as Docker Containers. Some Openstack services like Nova is composed of multiple Containers.
- Infrastructure components like Ceph, Openvswitch, Mongodb are also deployed as Containers.
- For Container deployment, Openstack natively uses Ansible. Kubernetes can also be used for Orchestration.
- Using Containers for Openstack service containers gives all the build, ship and deploy advantages of Containers.
- Using orchestration solution like Kubernetes gives all the resiliency and deployment advantages for Openstack services.
This work also shows how Containers and VMs can work closely with each other for lot of use-cases. There are other Openstack projects like Magnum and Kuryr where there is an intersection between Containers and VMs. Magnum project deals with Container orchestration using Openstack and Kuryr project deals with doing Container networking using Openstack Neutron.