Google Cloud Platform Guide
===========================

.. gce_intro:

Introduction
--------------------------

Ansible + Google have been working together on a set of auto-generated
Ansible modules designed to consistently and comprehensively cover the entirety
of the Google Cloud Platform (GCP).

Ansible contains modules for managing Google Cloud Platform resources,
including creating instances, controlling network access, working with
persistent disks, managing load balancers, and a lot more.

These new modules can be found under a new consistent name scheme "gcp_*"
(Note: gcp_target_proxy and gcp_url_map are legacy modules, despite the "gcp_*"
name. Please use gcp_compute_target_proxy and gcp_compute_url_map instead).

Additionally, the gcp_compute inventory plugin can discover all
Google Compute Engine (GCE) instances
and make them automatically available in your Ansible inventory.

You may see a collection of other GCP modules that do not conform to this
naming convention. These are the original modules primarily developed by the
Ansible community. You will find some overlapping functionality such as with
the "gce" module and the new "gcp_compute_instance" module. Either can be
used, but you may experience issues trying to use them together.

While the community GCP modules are not going away, Google is investing effort
into the new "gcp_*" modules. Google is committed to ensuring the Ansible
community has a great experience with GCP and therefore recommends adopting
these new modules if possible.


Requisites
---------------
The GCP modules require both the ``requests`` and the
``google-auth`` libraries to be installed.

.. code-block:: bash

    $ pip install requests google-auth

Alternatively for RHEL / CentOS, the ``python-requests`` package is also
available to satisfy ``requests`` libraries.

.. code-block:: bash

    $ yum install python-requests

Credentials
-----------
It's easy to create a GCP account with credentials for Ansible. You have multiple options to
get your credentials - here are two of the most common options:

* Service Accounts (Recommended): Use JSON service accounts with specific permissions.
* Machine Accounts: Use the permissions associated with the GCP Instance you're using Ansible on.

For the following examples, we'll be using service account credentials.

To work with the GCP modules, you'll first need to get some credentials in the
JSON format:

1. `Create a Service Account <https://developers.google.com/identity/protocols/OAuth2ServiceAccount#creatinganaccount>`_
2. `Download JSON credentials <https://support.google.com/cloud/answer/6158849?hl=en&ref_topic=6262490#serviceaccounts>`_

Once you have your credentials, there are two different ways to provide them to Ansible:

* by specifying them directly as module parameters
* by setting environment variables

Providing Credentials as Module Parameters
``````````````````````````````````````````

For the GCE modules you can specify the credentials as arguments:

* ``auth_kind``: type of authentication being used (choices: machineaccount, serviceaccount, application)
* ``service_account_email``: email associated with the project
* ``service_account_file``: path to the JSON credentials file
* ``project``: id of the project
* ``scopes``: The specific scopes that you want the actions to use.

For example, to create a new IP address using the ``gcp_compute_address`` module,
you can use the following configuration:

.. code-block:: yaml

   - name: Create IP address
     hosts: localhost
     gather_facts: false

     vars:
       service_account_file: /home/my_account.json
       project: my-project
       auth_kind: serviceaccount
       scopes:
         - https://www.googleapis.com/auth/compute

     tasks:

      - name: Allocate an IP Address
        gcp_compute_address:
            state: present
            name: 'test-address1'
            region: 'us-west1'
            project: "{{ project }}"
            auth_kind: "{{ auth_kind }}"
            service_account_file: "{{ service_account_file }}"
            scopes: "{{ scopes }}"

Providing Credentials as Environment Variables
``````````````````````````````````````````````

Set the following environment variables before running Ansible in order to configure your credentials:

.. code-block:: bash

    GCP_AUTH_KIND
    GCP_SERVICE_ACCOUNT_EMAIL
    GCP_SERVICE_ACCOUNT_FILE
    GCP_SCOPES

GCE Dynamic Inventory
---------------------

The best way to interact with your hosts is to use the gcp_compute inventory plugin, which dynamically queries GCE and tells Ansible what nodes can be managed.

To be able to use this GCE dynamic inventory plugin, you need to enable it first by specifying the following in the ``ansible.cfg`` file:

.. code-block:: ini

  [inventory]
  enable_plugins = gcp_compute

Then, create a file that ends in ``.gcp.yml`` in your root directory.

The gcp_compute inventory script takes in the same authentication information as any module.

Here's an example of a valid inventory file:

.. code-block:: yaml

    plugin: gcp_compute
    projects:
      - graphite-playground
    auth_kind: serviceaccount
    service_account_file: /home/alexstephen/my_account.json


Executing ``ansible-inventory --list -i <filename>.gcp.yml`` will create a list of GCP instances that are ready to be configured using Ansible.

Create an instance
``````````````````

The full range of GCP modules provide the ability to create a wide variety of
GCP resources with the full support of the entire GCP API.

The following playbook creates a GCE Instance. This instance relies on other GCP
resources like Disk. By creating other resources separately, we can give as
much detail as necessary about how we want to configure the other resources, for example
formatting of the Disk. By registering it to a variable, we can simply insert the 
variable into the instance task. The gcp_compute_instance module will figure out the
rest.

.. code-block:: yaml

   - name: Create an instance
     hosts: localhost
     gather_facts: false
     vars:
         gcp_project: my-project
         gcp_cred_kind: serviceaccount
         gcp_cred_file: /home/my_account.json
         zone: "us-central1-a"
         region: "us-central1"

     tasks:
      - name: create a disk
        gcp_compute_disk:
            name: 'disk-instance'
            size_gb: 50
            source_image: 'projects/ubuntu-os-cloud/global/images/family/ubuntu-1604-lts'
            zone: "{{ zone }}"
            project: "{{ gcp_project }}"
            auth_kind: "{{ gcp_cred_kind }}"
            service_account_file: "{{ gcp_cred_file }}"
            scopes:
              - https://www.googleapis.com/auth/compute
            state: present
        register: disk
      - name: create a address
        gcp_compute_address:
            name: 'address-instance'
            region: "{{ region }}"
            project: "{{ gcp_project }}"
            auth_kind: "{{ gcp_cred_kind }}"
            service_account_file: "{{ gcp_cred_file }}"
            scopes:
              - https://www.googleapis.com/auth/compute
            state: present
        register: address
      - name: create a instance
        gcp_compute_instance:
            state: present
            name: test-vm
            machine_type: n1-standard-1
            disks:
              - auto_delete: true
                boot: true
                source: "{{ disk }}"
            network_interfaces:
                - network: null # use default
                  access_configs:
                    - name: 'External NAT'
                      nat_ip: "{{ address }}"
                      type: 'ONE_TO_ONE_NAT'
            zone: "{{ zone }}"
            project: "{{ gcp_project }}"
            auth_kind: "{{ gcp_cred_kind }}"
            service_account_file: "{{ gcp_cred_file }}"
            scopes:
              - https://www.googleapis.com/auth/compute
        register: instance

      - name: Wait for SSH to come up
        wait_for: host={{ address.address }} port=22 delay=10 timeout=60

      - name: Add host to groupname
        add_host: hostname={{ address.address }} groupname=new_instances


   - name: Manage new instances
     hosts: new_instances
     connection: ssh
     become: True
     roles:
       - base_configuration
       - production_server

Note that use of the "add_host" module above creates a temporary, in-memory group.  This means that a play in the same playbook can then manage machines
in the 'new_instances' group, if so desired.  Any sort of arbitrary configuration is possible at this point.

For more information about Google Cloud, please visit the `Google Cloud website <https://cloud.google.com>`_.

Migration Guides
----------------

gce.py -> gcp_compute_instance.py
`````````````````````````````````
As of Ansible 2.8, we're encouraging everyone to move from the ``gce`` module to the
``gcp_compute_instance`` module. The ``gcp_compute_instance`` module has better
support for all of GCP's features, fewer dependencies, more flexibility, and
better supports GCP's authentication systems.

The ``gcp_compute_instance`` module supports all of the features of the ``gce``
module (and more!). Below is a mapping of ``gce`` fields over to
``gcp_compute_instance`` fields.

============================  ==========================================  ======================
 gce.py                        gcp_compute_instance.py                     Notes
============================  ==========================================  ======================
 state                        state/status                                State on gce has multiple values: "present", "absent", "stopped", "started", "terminated". State on gcp_compute_instance is used to describe if the instance exists (present) or does not (absent). Status is used to describe if the instance is "started", "stopped" or "terminated".
 image                        disks[].initialize_params.source_image      You'll need to create a single disk using the disks[] parameter and set it to be the boot disk (disks[].boot = true)
 image_family                 disks[].initialize_params.source_image      See above.
 external_projects            disks[].initialize_params.source_image      The name of the source_image will include the name of the project.
 instance_names               Use a loop or multiple tasks.               Using loops is a more Ansible-centric way of creating multiple instances and gives you the most flexibility.
 service_account_email        service_accounts[].email                    This is the service_account email address that you want the instance to be associated with. It is not the service_account email address that is used for the credentials necessary to create the instance.
 service_account_permissions  service_accounts[].scopes                   These are the permissions you want to grant to the instance.
 pem_file                     Not supported.                              We recommend using JSON service account credentials instead of PEM files.
 credentials_file             service_account_file
 project_id                   project
 name                         name                                        This field does not accept an array of names. Use a loop to create multiple instances.
 num_instances                Use a loop                                  For maximum flexibility, we're encouraging users to use Ansible features to create multiple instances, rather than letting the module do it for you.
 network                      network_interfaces[].network
 subnetwork                   network_interfaces[].subnetwork
 persistent_boot_disk         disks[].type = 'PERSISTENT'
 disks                        disks[]
 ip_forward                   can_ip_forward
 external_ip                  network_interfaces[].access_configs.nat_ip  This field takes multiple types of values. You can create an IP address with ``gcp_compute_address`` and place the name/output of the address here. You can also place the string value of the IP address's GCP name or the actual IP address.
 disks_auto_delete            disks[].auto_delete
 preemptible                  scheduling.preemptible
 disk_size                    disks[].initialize_params.disk_size_gb
============================  ==========================================  ======================

An example playbook is below:

.. code:: yaml

  gcp_compute_instance:
      name: "{{ item }}"
      machine_type: n1-standard-1
      ... # any other settings
      zone: us-central1-a
      project: "my-project"
      auth_kind: "service_account_file"
      service_account_file: "~/my_account.json"
      state: present
  loop:
    - instance-1
    - instance-2
