Allow randomness in instance names or use instance IDs

[berendt]

Issue Type

• Feature request

Current Behaviour

At the moment it is possible to specify the used OpenStack instance names in the configuration. The problem is that those names are unique. This way it is not possible to run the same configuration multiple times. In my CI I want to use the same configuration to run in parallel to be able to kickoff multiple jobs in parallel and to run Ansible 2.2 and Ansible 2.3 tests in parallel.

Desired Behaviour

It should be possible to use one configuration in parallel.

[retr0h]

molecule.yml can accept env vars. Just have your CI system use a wrapper script which can generate a random name and set RANDOM_NAME prior to executing molecule.

platforms:
  - name: $RANDOM_NAME
    image: centos:latest

[berendt]

Ah cool, I was not aware of this feature. I think this should work for my use cased. Will test this today.

[berendt]

Tested this with version 1.25 and the OpenStack driver. But the variable is not replaced, I receive $VARNAME in the instance name.

[retr0h]

Ah, yeah. Molecule expands the env vars when the config is parsed. However, the Ansible playbook is loading the file off disk. I have an idea. Once I land #894 I'll fix this.

[Lirt]

I feel like the names should be internally randomized by molecule in first run and remembered (as you already do in file /tmp/molecule/<ROLE>/<SCENARIO>/ansible_inventory.yml) to avoid instance name conflicts when working in teams and simultaneously using CIs.

Using non-deterministic IDs is currently unusable, since on each command the instance name is different and you cannot target already created machine.

My workaround for this is using "$HOSTNAME" in the instance name, but this is not 100% bulletproof I guess.

[decentral1se]

Think this is related to #1573 and #1702.

We need to solve this I think ...

[Frodox]

@retr0h what do you mean by

Just have your CI system use a wrapper script which can generate a random name and set RANDOM_NAME prior to executing molecule.

?
I run molecule as

docker run --rm \
    ... \
    molecule \
    molecule test

and several platforms as

---
dependency:
  name: galaxy
driver:
  name: openstack
lint:
  name: yamllint
platforms:
  - name: ${RANDOM_NAME}
    image: "Ubuntu 16.04"
    flavor: "d1.c1r1"
  - name: ${RANDOM_NAME}
    image: "Ubuntu 18.04"
    flavor: "d1.c1r1"
provisioner:
  name: ansible
  lint:
    name: ansible-lint
scenario:
  name: default
verifier:
  name: testinfra
  lint:
    name: flake8

So, where should I inject generation of RANDOM_NAME, since ansible-playbook runs it in parallel / lookup envs only once