gce-deploy-action

README

Deploy to Google Compute Engine

Github action to simplify deploys to Google Compute Engine. The action will perform a rolling update with a new Instance Template using the Instance Group Manager.

Concept

Managed instance groups support stateless apps that don't depend on the specific state of the underlying VM instances to run. This enables features like autoscaling and autohealing, where the managed instance group can delete and recreate instances automatically. Read more

Google Cloud Load Balancer can use an instance group as a backend service to distribute traffic across VM instances. Read more

Using the Container-Optimized OS and cloud-init, which can be set in the Instance Template, additional configuration can be applied when the instance boots. Alternativaly startup scripts can be used to run scripts at boot time. Read more

tldr This action will:

1. Clone an existing instance template (using it as base).
2. Update metadata config of the newly created instance template to run a startup script.
3. Tell the instance group manager to perform a rolling update with the new instance template.

Prerequisites

Set up the following resources manually in the Cloud Console or use a tool like Terraform.

• Create a base instance template to be cloned by this action.
• Create a managed instance group. Please note that currently only regional instance groups are supported.
• Set up Load Balancer to use instance group as backend service.
• Create Service Account with Roles "Compute Admin" and "Service Account User" and export a new JSON key.

Config

By default this action expects a deploy.yml in the root directory of the repository. Environment variables (syntax $FOO or ${FOO}) used in this file are replaced automatically. List of default variables.

Variable	Description
deploys.*.name	Required Name of the deploy
deploys.*.project	Name of the Google Cloud project
deploys.*.google_application_credentials	Either a path or the contents of a Service Account JSON Key. Required, if not specified in Github action.
deploys.*.region	Required Region of the instance group.
deploys.*.instance_group	Required Name of the instance group.
deploys.*.instance_template_base	Required Instance template to be used as base.
deploys.*.instance_template	Required Name of the newly created instance template.
deploys.*.startup_script	Path to script to run when VM boots. Read more
deploys.*.shutdown_script	Path to script to run when VM shuts down. Read more
deploys.*.cloud_init	Path to cloud-init file. Read more
deploys.*.vars	A set of additional key/value variables which will be available as variables (syntax $(FOO)) in either startup_script, shutdown_script or cloud_init. Vars take precedence over ENV vars.
deploys.*.labels	A set of key/value label pairs to assign to instances.
deploys.*.metadata	A set of key/value metadata pairs to make available from within instances.
deploys.*.tags	A list of tags to assign to instances.

Example deploy.yml

deploys:
  - name: my-app-deploy
    region: us-central1
    instance_group: my-app-instance-group
    instance_template_base: my-app-instance-template-base
    instance_template: my-app-$GITHUB_RUN_NUMBER-$GITHUB_SHA
    cloud_init: cloud-init.yml # see example dir
    labels:
      github-sha: $GITHUB_SHA
    tags:
      - my-tag123

Github Action Inputs

Variable	Description
dir	Working directory. Defaults to root directory of repository.
config	Path to config file. Default deploy.yml or deploy.yaml.
google_application_credentials	Either a path or the contents of a Service Account JSON Key.

Example Usage

uses: mattes/gce-deploy-action@master
with:
  config: production.yml
  google_application_credentials: ${{ secrets.GOOGLE_APPLICATION_CREDENTIALS }}