Performance of Nova list command

Another interesting result comes from the NovaServers.boot_and_list_server scenario, which enabled us to launch the following task with Rally:

  • Task context: 1 temporary OpenStack user.

  • Task scenario: boot a single VM from this user & list all VMs.

  • Task runner: repeat this procedure 200 times in a continuous way.

During the execution of this task, the user has more and more VMs on each iteration. Rally has shown that in this case, the performance of the VM list command in Nova is degrading much faster than one might expect:

Duration of nova.list_servers over 200 iterations. It grows from under 0.5 seconds in the first iterations to 2.5 to 4.5 seconds after the 100th.

Task

The same task in the current task format:

---
version: 2
title: Performance of Nova list command
subtasks:
  - title: Boot a server and list all servers
    scenario:
      NovaServers.boot_and_list_server:
        flavor:
          name: "{{ flavor_name }}"
        image:
          name: "{{ image_name }}"
    runner:
      serial:
        times: 200
    contexts:
      users:
        tenants: 1
        users_per_tenant: 1

The flavor and the image are task arguments; pass them when you start the task:

$ rally task start list-servers.yaml --task-args '{"flavor_name": "m1.tiny", "image_name": "cirros"}'