playbook.yaml

- name: Some play
  hosts: localhost
  connection: local
  vars:
    etcd_image: quay.io/coreos/etcd:v3.1.3
    etcd_cluster_name: etcd
    etcd_cluster_size: 5
  pre_tasks:

    - name: "Create list for the initial etcd cluster"
      set_fact:
        etcd_initial_cluster: []

    - name: "Add {{ etcd_count }} etcds to the initial etcd cluster"
      set_fact:
        etcd_initial_cluster:
          "{{ etcd_initial_cluster + ['%s-%s' | format(etcd_cluster_name, item)] }}"
      with_sequence: "count={{ etcd_cluster_size }}"

    - name: "initial cluster addresses"
      set_fact:
        etcd_initial_cluster_addresses: >-
          "{%- for i in etcd_initial_cluster -%}
          {{ '%s=http://%s:2380' | format(i, i) }}
          {%- if loop.index < etcd_initial_cluster|length %},{%- endif -%}
          {%- endfor -%}"

  tasks:
    - name: Create a network
      docker_network:
        name: etcd

    - name: Start some containers
      docker_container:
        name: "{{ item }}"
        image: "{{ etcd_image }}"
        ports:
          - 2379
          - 2380
        networks:
          - name: etcd
        command: >
          /usr/local/bin/etcd
          --name {{ item }}
          --data-dir=/etcd-data
          --initial-advertise-peer-urls http://{{ item }}:2380
          --listen-peer-urls http://{{ item }}:2380
          --advertise-client-urls http://{{ item }}:2379
          --listen-client-urls http://{{ item }}:2379
          --initial-cluster
          {{ etcd_initial_cluster_addresses }}
          --initial-cluster-state new
          --initial-cluster-token pe6o
      register: containers_result
      with_items: "{{ etcd_initial_cluster }}"

    - name: "Will debug current inventory groups and hosts"
      debug:
        msg: "{{ groups }}"
      when: containers_result|change

    - name: "Assert that image_{{ etcd_image }} is not available"
      assert:
        that:
          - "('image_%s' | format(etcd_image)) not in groups"
      when: containers_result|change

    - name: Refresh inventory
      include: refresh_inventory.yml
      static: no
      when: containers_result|change
      register: refresh_inventory

    - assert:
        that:
          - 'refresh_inventory|skip'
      when: containers_result|success

    - assert:
        msg: "Assert that group image_{{ etcd_image }} is available"
        that:
          - "('image_%s' | format(etcd_image)) in groups"

- name: Some other play
  hosts: "image_{{ etcd_image }}"
  connection: docker
  vars:
    etcd_image: quay.io/coreos/etcd:v3.1.3
  tasks:
    - debug:
        msg: "{{ inventory_hostname }}"

refresh_inventory.yaml

- name: refresh dynamic inventory
  meta: refresh_inventory

run1_output.txt

vagrant@vagrant-ubuntu-trusty-64:~$ ansible-playbook -i ./docker.py playbook.yaml -v
No config file found; using defaults

PLAY [Some play] ***************************************************************

TASK [setup] *******************************************************************
ok: [localhost]

TASK [Create list for the initial etcd cluster] ********************************
ok: [localhost] => {"ansible_facts": {"etcd_initial_cluster": []}, "changed": false}

TASK [Add {{ etcd_count }} etcds to the initial etcd cluster] ******************
ok: [localhost] => (item=1) => {"ansible_facts": {"etcd_initial_cluster": ["etcd-1"]}, "changed": false, "item": "1"}
ok: [localhost] => (item=2) => {"ansible_facts": {"etcd_initial_cluster": ["etcd-1", "etcd-2"]}, "changed": false, "item": "2"}
ok: [localhost] => (item=3) => {"ansible_facts": {"etcd_initial_cluster": ["etcd-1", "etcd-2", "etcd-3"]}, "changed": false, "item": "3"}
ok: [localhost] => (item=4) => {"ansible_facts": {"etcd_initial_cluster": ["etcd-1", "etcd-2", "etcd-3", "etcd-4"]}, "changed": false, "item": "4"}
ok: [localhost] => (item=5) => {"ansible_facts": {"etcd_initial_cluster": ["etcd-1", "etcd-2", "etcd-3", "etcd-4", "etcd-5"]}, "changed": false, "item": "5"}

TASK [initial cluster addresses] ***********************************************
ok: [localhost] => {"ansible_facts": {"etcd_initial_cluster_addresses": "\"etcd-1=http://etcd-1:2380,etcd-2=http://etcd-2:2380,etcd-3=http://etcd-3:2380,etcd-4=http://etcd-4:2380,etcd-5=http://etcd-5:2380\""}, "changed": false}

TASK [Create a network] ********************************************************
ok: [localhost] => {"ansible_facts": {}, "changed": false}

TASK [Start some containers] ***************************************************
changed: [localhost] => (item=etcd-1) => {"ansible_facts": {}, "changed": true, "item": "etcd-1"}
changed: [localhost] => (item=etcd-2) => {"ansible_facts": {}, "changed": true, "item": "etcd-2"}
changed: [localhost] => (item=etcd-3) => {"ansible_facts": {}, "changed": true, "item": "etcd-3"}
changed: [localhost] => (item=etcd-4) => {"ansible_facts": {}, "changed": true, "item": "etcd-4"}
changed: [localhost] => (item=etcd-5) => {"ansible_facts": {}, "changed": true, "item": "etcd-5"}

TASK [Will debug current inventory groups and hosts] ***************************
ok: [localhost] => {
    "msg": {
        "all": [
            "unix://var/run/docker.sock"
        ],
        "docker_hosts": [
            "unix://var/run/docker.sock"
        ],
        "ungrouped": [
            "localhost"
        ]
    }
}

TASK [Assert that group image_quay.io/coreos/etcd:v3.1.3 is not available on first run] ***
ok: [localhost] => {
    "changed": false,
    "msg": "All assertions passed"
}

TASK [Refresh inventory] *******************************************************
included: /home/vagrant/refresh_inventory.yml for localhost

TASK [Assert that refresh_inventory is skipped when not first run] *************
skipping: [localhost] => {"changed": false, "skip_reason": "Conditional check failed", "skipped": true}

TASK [Assert that group image_quay.io/coreos/etcd:v3.1.3 is available] *********
ok: [localhost] => {
    "changed": false,
    "msg": "All assertions passed"
}

PLAY RECAP *********************************************************************
localhost                  : ok=10   changed=1    unreachable=0    failed=0

run2_output.txt

vagrant@vagrant-ubuntu-trusty-64:~$ ansible-playbook -i ./docker.py playbook.yaml -v
No config file found; using defaults

PLAY [Some play] ***************************************************************

TASK [setup] *******************************************************************
ok: [localhost]

TASK [Create list for the initial etcd cluster] ********************************
ok: [localhost] => {"ansible_facts": {"etcd_initial_cluster": []}, "changed": false}

TASK [Add {{ etcd_count }} etcds to the initial etcd cluster] ******************
ok: [localhost] => (item=1) => {"ansible_facts": {"etcd_initial_cluster": ["etcd-1"]}, "changed": false, "item": "1"}
ok: [localhost] => (item=2) => {"ansible_facts": {"etcd_initial_cluster": ["etcd-1", "etcd-2"]}, "changed": false, "item": "2"}
ok: [localhost] => (item=3) => {"ansible_facts": {"etcd_initial_cluster": ["etcd-1", "etcd-2", "etcd-3"]}, "changed": false, "item": "3"}
ok: [localhost] => (item=4) => {"ansible_facts": {"etcd_initial_cluster": ["etcd-1", "etcd-2", "etcd-3", "etcd-4"]}, "changed": false, "item": "4"}
ok: [localhost] => (item=5) => {"ansible_facts": {"etcd_initial_cluster": ["etcd-1", "etcd-2", "etcd-3", "etcd-4", "etcd-5"]}, "changed": false, "item": "5"}

TASK [initial cluster addresses] ***********************************************
ok: [localhost] => {"ansible_facts": {"etcd_initial_cluster_addresses": "\"etcd-1=http://etcd-1:2380,etcd-2=http://etcd-2:2380,etcd-3=http://etcd-3:2380,etcd-4=http://etcd-4:2380,etcd-5=http://etcd-5:2380\""}, "changed": false}

TASK [Create a network] ********************************************************
ok: [localhost] => {"ansible_facts": {}, "changed": false}

TASK [Start some containers] ***************************************************
ok: [localhost] => (item=etcd-1) => {"ansible_facts": {}, "changed": false, "item": "etcd-1"}
ok: [localhost] => (item=etcd-2) => {"ansible_facts": {}, "changed": false, "item": "etcd-2"}
ok: [localhost] => (item=etcd-3) => {"ansible_facts": {}, "changed": false, "item": "etcd-3"}
ok: [localhost] => (item=etcd-4) => {"ansible_facts": {}, "changed": false, "item": "etcd-4"}
ok: [localhost] => (item=etcd-5) => {"ansible_facts": {}, "changed": false, "item": "etcd-5"}

TASK [Will debug current inventory groups and hosts] ***************************
skipping: [localhost] => {"changed": false, "skip_reason": "Conditional check failed", "skipped": true}

TASK [Assert that group image_quay.io/coreos/etcd:v3.1.3 is not available on first run] ***
skipping: [localhost] => {"changed": false, "skip_reason": "Conditional check failed", "skipped": true}

TASK [Refresh inventory] *******************************************************
skipping: [localhost] => {"changed": false, "skip_reason": "Conditional check failed", "skipped": true}

TASK [Assert that refresh_inventory is skipped when not first run] *************
ok: [localhost] => {
    "changed": false,
    "msg": "All assertions passed"
}

TASK [Assert that group image_quay.io/coreos/etcd:v3.1.3 is available] *********
ok: [localhost] => {
    "changed": false,
    "msg": "All assertions passed"
}

PLAY RECAP *********************************************************************
localhost                  : ok=8    changed=0    unreachable=0    failed=0