Wsrtjtyk

I need to check if VMs exist or not. The check is registered in one play, 'control' and referenced in another, 'production'. What is the correct format for this?

create_vm.yml:

---

- hosts: control

  tasks:

  - name: Check VM

    virt:

      command: "list_vms"

    register: vms



- hosts: production

  tasks:

  - name: Create VM

  STUFF

  when: inventory_hostname not in groups['control']['vms']

I've tried different 'when' formats but they've all failed.

I have various errors depending on the format of when condition used; the following is for the specified condition.

fatal: [prod-operator]: FAILED! => {"failed": true, "msg": "The conditional check 'inventory_hostname not in groups['control']['vms']' failed. The error was: error while evaluating conditional (inventory_hostname not in groups['control']['vms']): Unable to look up a name or access an attribute in template string ({% if inventory_hostname not in groups['control']['vms'] %} True {% else %} False {% endif %}).nMake sure your variable name does not contain invalid characters like '-': argument of type 'StrictUndefined' is not iterablennThe error appears to have been in '/root/micks-ci-setup/production/virtual_machine/create-vm.yml': line 29, column 5, but maynbe elsewhere in the file depending on the exact syntax problem.nnThe offending line appears to be:nnn - name: Create Production VMn ^ heren"}

From what I've seen I should be able to reference the registered value form another task using a reference to host but it just won't work for me. I'll move on with a workaround of performing another check in the hosts: production play as follows.

(I'm doing a round-robin deployment of VMs hence the delegate_to complexity)

---

- hosts: control

  tasks:

  - name: Check VM

    virt:

      command: "list_vms"

    register: vms



- hosts: production

  tasks:

  - name: Check VMs

    virt:

      command: "list_vms"

    register: vms

    delegate_to: '{{ groups["control"][play_hosts.index(inventory_hostname) % groups["control"]|length] }}'

And when condition as follows:

when: inventory_hostname not in vms.list_vms

If anyone can provide the "correct" method or a reason why it's not working for me then please feel free to post another answer.