GitOps automation for SLATE instances

This repository provides a reference implementation of GitOps style automation for SLATE instances. This automation consists of:

-A small Python script, PushUpdates.py, responsible for reading changes and issuing requests to the SLATE API

-A GitHub Actions workflow for detecting changes and running the Python updater

The workflow looks for files that match values.yaml and instance.yaml. When a file associated with an instance is modified the workflow will update that instance. If a file is added, it will be deployed as a new instance.

Setup

Place the Values file values.yaml into a directory that represents the instance for each instance you want to manage. The directory can have any name, and can be nested. The values file must be called exactly values.yaml. Files at the repository root will be ignored. You will also need an instance.yaml for each instance.

Example:

    MY_INSTANCE/values.yaml
    MY_INSTANCE/instance.yaml

SLATE Token

You will need to add your SLATE user token (obtained from portal.slateci.io/cli) as a repository secret on your GitHub repository. To do this:

1. Navigate to Settings on the top bar of the GitHub repository interface
2. Choose Secrets from the left-hand side bar menu
3. Click the button that says New repository secret upper right
4. Name the secret SLATE_API_TOKEN

instance.yaml

For each instance, you must also have a file called instance.yaml that contains some details about the instance. For existing instances, only the instance field is needed to provide the ID. Info about the cluster, group, and app can be used to automatically deploy new instances too.

Optionally you can specify and update the version of the SLATE application with the version field in instance.yaml. If version is unspecified the latest version is the default.

New Instances

To deploy new instances you must include the cluster, group, and app. Version is optional.

    cluster: uutah-prod
    group: slate-dev
    app: nginx
    version: 1.2.0

Existing instances

To manage existing instances you only need to specify a SLATE instanceID.

    instance: instance_BrX9HtpP1L0

Copy the workflow

Once everything is setup, copy PushUpdates.py and .github/workflows/slate-deployment.yml into your repository.

Enable Actions in the GitHub UI

Once the workflow is added to the repository, you must allow it to run by navigating to the Actions tab in GitHub's interface.

Git force pushes

Force pushes rewrite history in git, and can corrupt the state of your instances. Force pushing should be avoided.

Other issues

If instance deletion is desired, it must currently be performed manually.

The automation will writeback the instance ID for instances that get deployed, this should be refactored to happen on a branch.