This is a continuation of my previous blog on Openstack and Docker. In this blog, I will cover Openstack Docker heat plugin and Magnum.
Following are some of the items that Nova Docker driver cannot do currently:
- Passing environment variables
- Linking containers
- Specifying volumes
- Orchestrating and scheduling the containers
Heat docker plugin solves problems 1-3 and partially solves problem 4. Following is the architecture diagram I found in Openstack Docker wiki for heat.
- Nova is not involved here. Openstack heat uses Docker plugin to talk to Docker agent on the host.
- The host here is the VM spawned. The VM can either be spawned by Nova or Heat can spawn this using Nova driver.
- Glance is not involved here as the container images are stored in Docker registry.
- The Heat approach allows us to specify environment variables, link containers, specify volumes as well as orchestrate the host on which the Docker runs.
