Playbook tasks vs Role tasks

[b...@tanners.org]

I think I'm missing something fundamental.

I have a Playbook for doing Google Computer Engine (gce) stuff and it's based on playbooks I found on the Internet. The tasks are defined within the playbook.

- name: google compute engine testing

  hosts: localhost

  connection: localhost

  gather_facts: no

  vars:

    project_id: AAAA

    instance_names: BBBB

    service_account_email: m...@AAAA.iam.gserviceaccount.com

    credentials_file: CCCCC

    image: ubuntu-1604-xenial-v20160721

    machine_type: f1-micro

    zone: us-central1-b

  tasks:

    - name: create instance

      gce:

        instance_names: "{{ instance_names }}"

        zone: "{{ zone }}"

        machine_type: "{{ machine_type }}"

        image: "{{ image }}"

        project_id: "{{ project_id }}"

        credentials_file: "{{ credentials_file }}"

        service_account_email: "{{ service_account_email }}"

      register: gce

      tags: google

    - name: wait for ssh

      wait_for:

        host: "{{ item.public_ip }}"

        port: 22 

        delay: 10 

        timeout: 60 

        state: started

      with_items: "{{ gce.instance_data }}"

      tags: google

How would I change this into a Role called gce-instance?

I assume the vars: and tasks would just move to the Role's tasks/main.yml)?

But how do I get the below stuff into the Role?

- name: google compute engine testing

  hosts: localhost

  connection: localhost

  gather_facts: no

Sample Playbook 

- hosts: all

  vars:

  pre_tasks:

  roles:

    - { role: gce-instance }

I do not understand what 

- name: google compute engine testing

  hosts: localhost

  connection: localhost

  gather_facts: no

does. Is it setting up defaults for the below tasks?

  tasks:

    # gcloud compute machine-types list

    # gcloud compute images list

    #

    - name: create instance

      gce:

        instance_names: "{{ instance_names }}"

        zone: "{{ zone }}"

        machine_type: "{{ machine_type }}"

        image: "{{ image }}"

        project_id: "{{ project_id }}"

        credentials_file: "{{ credentials_file }}"

        service_account_email: "{{ service_account_email }}"

      register: gce

      tags: google

[Brian Coca]

first of all:

connection: localhost 

is wrong, you can omit it as the 'implicit localhost' already uses a local connection or use:

connection: local

So roles are meant to reuse tasks, even so you still need to setup target hosts, in the case of cloud modules that 'target' is normally localhost (target is where the module executes). 

That is why you always need a play, as roles do not target hosts, just provide a set of tasks and resources to run.

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Brian Coca