How to connect Terraform Operator for Kubernetes to an existing agent pool

Introduction

The Terraform Enterprise environment has an agent pool with workspaces connected to it. The Terraform Operator for Kubernetes has been implemented and you want to bring the existing agent pool under the Terraform Operator for Kubernetes management. 

Existing agent pool in Terraform Enterprise called example

The following Kubernetes manifest defines the AgentPool resource you want to create:

apiVersion: app.terraform.io/v1alpha2
kind: AgentPool
metadata:
  name: example
  namespace: orange
spec:
  organization: test
  token:
    secretKeyRef:
      name: terraformrc
      key: token
  name: example
  agentTokens:
    - name: example
  agentDeployment:
    replicas: 1
    spec:
      containers:
        - name: tfc-agent
          image: "hashicorp/tfc-agent:1.22.2"
# Enable autoscaling
  autoscaling:
    minReplicas: 2
    maxReplicas: 5
    targetWorkspaces:
    - wildcardName: test*
    cooldownPeriod:
      scaleUpSeconds: 30
      scaleDownSeconds: 30

Apply it using the command:

kubectl apply -f agentpool.yaml

agentpool.app.terraform.io/example created

The Terraform Operator show the follow error in the logs and no agents are starting

ERROR Reconcile Agent Pool {"agentpool": {"name":"example","namespace":"orange"}, 
"msg": "failed to create a new agent pool", 
"error": "invalid attribute\n\nName is already taken within the organization"} 

Expected Outcome

Adding the existing agent pool to the Terraform Operator management

Prerequisites

• Have the Terraform Operator for Kubernetes configured as described here

Procedure

• Get the agentpool id from terraform Enterprise.
  • Go to the agent pool and click on the agent pool and the url should contain something like the following apool-bN3GijECCj9YmVa8. This is the ID we need

• Retrieve the metadata.generation of the AgentPool Resource
  • To get the YAML output of the current AgentPool resource and extract the metadata.generation value

kubectl -n <namespace> get agentpool <metadata.name> -o yaml |grep generation

example

kubectl -n orange get agentpool example -o yaml |grep generation
generation: 2

• Update your agentpool resource with the following

kubectl patch -n <namespace> agentpool <metadata.name> --type=merge --subresource status --patch 'status: {observedGeneration: <metadata.generation>, agentPoolID: <agentpool_id>}'

Example with the above data

kubectl patch -n orange agentpool example --type=merge --subresource status --patch 'status: {observedGeneration: 2, agentPoolID: apool-WGaTSkPAnPtZWXR3}' 

• Now it should succeed and you should see the agents start and connect

Additional Information

• Terraform Operator for Kubernetes Github repository can be found here
• Official documentation for the Terraform Operator can be found here