evacuate.yaml

---
version: '2.0'
evacuate_workflow:
  output:
    list_instances: <% $.list_instances %>
  tasks:
    get_host_failed:
      action: nova.hypervisors_list
      publish:
        list_host_failed: <% task(get_host_failed).result.where($.state = "down").select($.hypervisor_hostname) %>
      on-success:
        - instances_list: <% len($.list_host_failed) > 0 %>
    instances_list:
      action: nova.servers_list
      publish:
        list_instances: <% let(root => $ ) -> task(instances_list).result.where($.get("OS-EXT-SRV-ATTR:hypervisor_hostname") = $root.list_host_failed.first() ).select($.id) %>
      on-success:
        - list_all_hypervisors: <% len($.list_instances) > 0 %>
    list_all_hypervisors:
      action: nova.hypervisors_list
      publish:
        all_hypervisor_active: <% let(root => $) -> task(list_all_hypervisors).result.where($.hypervisor_hostname != $root.list_host_failed.first()).select($.hypervisor_hostname) %>
      on-success:
        - evacuate_instances
    evacuate_instances:
      with-items:
        - instance in <% $.list_instances %>
      action: nova.servers_evacuate server=<% $.instance %> host=<% $.all_hypervisor_active[ random(0,len($.all_hypervisor_active)-1 )] %>
      on-success:
        - succeed