[FEATURE] - Drift Detection

[gambol99]

Drift detection when enabled by spec.enableDriftDetection periodicallyruns the terraform plan. It checks for drift from the expected state and if found, changes the status and raises an event against the resource. Effectively this is running another terraform plan and using the result to determine a change.

You can enable drift detection via

---
apiVersion: terraform.appvia.io/v1alpha1
kind: Configuration
metadata:
  name: bucket
spec:
  # ssh git::ssh://git@example.com/foo/bar
  module: https://github.com/terraform-aws-modules/terraform-aws-s3-bucket.git?ref=v3.1.0

  providerRef:
    namespace: terraform-system
    name: aws

  enableDriftDetection: true 

The controller has two new settings

• Drift Interval - which is the minimum amount of time it will wait before kicking a drift check
• Drift Threshold - which is the max percentage of configuratoins which can be running a drift at once. This ensure you don't overwhelm the cloud provider.

Note a new status field has been added to the resource which provides an overall status to the resources

[jest@starfury terraform-controller]$ k -n apps get configurations.terraform.appvia.io
NAME     MODULE                                                                            SECRET   ESTIMATED     SYNCHRONIZED   AGE
bucket   https://github.com/terraform-aws-modules/terraform-aws-s3-bucket.git?ref=v3.1.0   test     Not Enabled   InSync         3m5s

On detecting a resource has drifted the status will move to OutOfSync and a kubernetes event will be raised.