In this section, we will now create the playbook and role that will allow you to migrate an instance to a specific compute node using the traditional nova migrate command. Unlike the other tasks that we have created so far, there is really only one way to handle this task. We will take the steps outlined in the preceding two sections, automate them to make sure that we have to supply only a few variable values, and then execute only one command.
This chapter started off with talking about instance migration and how there are two options within Nova to handle this; namely, traditional migration and live-migration. The traditional migration process is basically a one step process but in order to properly automate this task we will need to add a few more steps to the process. A brief outline of the tasks that we will have to create are:
List the compute nodes.
Collect pre-migration instance details.
Disable all compute nodes except for the one we want the instance...