Configuring Terraform Runner

Customizing Fetch Interval

By default, Terraform Runner will run fetch (terraform plan) every 5 minutes. After the Service Instance converges, the fetch will run every hour to check for drifts. Both intervals can be customized:

runtime:
  terraformRunner:
    pollInterval: 300s  # interval when not converged
    steadyStatePollInterval: 3600s  # interval when converged
    ...

Templatizing Terraform Modules and Sharing Between Release Channels

Via the use of Terraform variables, you can reuse a single Terraform module source code across all your Release Channels. To do this, use extraInitArgs to pass additional -backend-config that is Release Channel specific, ensuring that each module's state is independent, then pass whatever extra variables are needed as environment variables.

service:
  name: my-tf-service
  application: my-app
  customRuntime:
    parameterValues:
      - name: image
        string: ...  # as needed
      - name: extraInitArgs
        string: '-backend-config="my-config=something/with/{{.Builtins.ReleaseChannel.Name}}"'
      - name: path
        string: ...  # as needed
  env:
    TF_VAR_release_channel_name:
      value: "{{.Builtins.ReleaseChannel.Name}}"

You can further combine this with Release-Channel-level constants for complex templating and Release-Channel-level environment variables to set variables at a Release-Channel level across all Services.