Using the Google Compute Engine public cloud

Juju already has knowledge of the GCE cloud, so unlike previous versions there is no need to provide a specific configuration for it, it 'just works'. GCE will appear in the list of known clouds when you issue the command:

juju clouds

And you can see more specific information (e.g. the supported regions) by running:

juju show-cloud google

If at any point you believe Juju's information is out of date (e.g. Google just announced support for a new region), you can update Juju's public cloud data by running:

juju update-clouds

Preparing your GCE cloud for use by Juju

Although Juju knows how GCE works, there are some tasks you must perform manually in the GCE dashboard to prepare your account to work with Juju. We give an overview of the steps here. For greater detail, see the GCE site and the official GCE documentation.

Create a project

Firstly, you should create a new project for Juju. If you have already used GCE your existing projects will be listed in the pull-down menu with one being selected as your currently active project (here 'My First Project'). The dialog is found near the top-right corner:

create_gce_project_dropdown

Enter a project name (here 'My Juju-GCE Project'):

create_gce_project_details

The project id (used later) will be generated automatically. Click 'Edit' to change it.

Enable the GCE API

The Google Compute Engine API needs to be enabled for your new project in order for Juju to communicate with it. This is done automatically if a "billing method" has been set up. By following the below steps you will discover whether you need to set up billing or not.

At the top-left of the web UI there is an icon representing 'Products & services'. It is denoted by this icon, next to the 'Google Cloud Platform' title:

Product & services icon

Click through and select 'API Manager'. By default you will be on the 'Overview' screen, it will show this across the top:

API Manager screen

Click '+Enable API' and then from the list of available APIs you are shown, select 'Compute Engine API':

Compute Engine API

On the top of the page that opens, click 'Enable'. If the API is already enabled, this will display 'Disable'. Clicking it may prompt you to set up a billing method (if not already done).

Download credentials

Juju will need credential information to authenticate itself to the GCE cloud. This is provided in the form of a file which can be generated and downloaded from GCE.

In the GCE web interface, navigate back to the 'API Manager' screen you used above, and choose the 'Credentials' screen. By default you will be within the 'Credentials' tab. Click the 'Create credentials' button and choose 'Service account key' from the 3 options available:

Create credentials dialog #1

In the ensuing dialog, select 'Compute Engine default service account' and 'JSON' key type:

Create credentials dialog #2

Once the 'Create' button is pressed you will be prompted to download a file. This is the file we're after. Store it safely as this file cannot be regenerated (although a new one can easily be created).

Place this file where the Juju client can find it. This may or may not be on the computer you downloaded the file to. We recommend storing this file in the default Juju directory, to ensure that it is with your other Juju files in whatever system backups you perform.

For the current example, say the file is called My-Juju-GCE-Project-f33a6cdbd8e3.json (based on our project name of 'My Juju-GCE Project'), on Ubuntu we would store it here:

~/.local/share/juju/Juju-GCE-f33a6cdbd8e3.json

Or, you may place this information into a file at ~/.config/gcloud/application_default_credentials.json, or %APPDATA%/gcloud/application_default_credentials.json on Windows. It is also valid to set an environment variable GOOGLE_APPLICATION_CREDENTIALS containing the credential information.

Credentials

Armed with the file downloaded above, you can add the credential with the command:

juju add-credential google

The command will interactively prompt you for information about the credentials being added. For the authentication type, choose 'json' and then give the full path to the file downloaded.