rally-openstack/samples/tasks/contexts/volume-types.yaml

---
  Dummy.openstack:
    -
      args:
        sleep: 0.1
      runner:
        type: "constant"
        times: 4
        concurrency: 2
      context:
        users:
          tenants: 1
          users_per_tenant: 2
        volume_types:
          - test