ARC Runner Terraform Deployment Skill

ARC Runner Terraform Deployment Skill

Overview

This skill covers Terraform patterns for deploying GitHub Actions Runner Controller (ARC) on Rackspace Spot Kubernetes. Key challenge: managing resources that depend on CRDs installed during the same apply.

Critical Learning: CRD Installation Timing

The Problem

When deploying ARC, ArgoCD Applications are CRDs that don't exist until ArgoCD Helm chart is installed. Using kubernetes_manifest fails:

Error: Provider produced inconsistent result after apply
The CRD "applications.argoproj.io" does not exist

The Solution: Use kubectl_manifest Instead

WRONG - kubernetes_manifest validates at plan time:

resource "kubernetes_manifest" "argocd_app" {
  manifest = {
    apiVersion = "argoproj.io/​v1alpha1"
    kind       = "Application"
    # ...
  }
}
# ERROR: CRD doesn't exist during terraform plan

CORRECT - kubectl_manifest applies at runtime:

resource "kubectl_manifest" "argocd_app" {
  yaml_body = yamlencode({
    apiVersion = "argoproj.io/​v1alpha1"
    kind       = "Application"
    # ...
  })

  depends_on = [
    helm_release.argocd,
    time_sleep.wait_for_crds
  ]
}

Why This Works

Pattern: CRD Registration Wait

After installing Helm charts that provide CRDs, add explicit wait:

resource "helm_release" "argocd" {
  name       = "argocd"
  chart      = "argo-cd"
  repository = "https://argoproj.github.io/​argo-helm"
  namespace  = "argocd"

  # ... chart configuration
}

resource "time_sleep" "wait_for_crds" {
  depends_on = [helm_release.argocd]

  create_duration = "30s"  # Wait for CRDs to register with K8s API
}

resource "kubectl_manifest" "bootstrap_app" {
  yaml_body = yamlencode({
    apiVersion = "argoproj.io/​v1alpha1"
    kind       = "Application"
    # ...
  })

  depends_on = [time_sleep.wait_for_crds]
}

Why 30 seconds?

• CRDs must register with Kubernetes API server
• API server must propagate to all control plane nodes
• 30s provides safe buffer for registration

Pattern: Namespace Management

The Conflict

When both Terraform and ArgoCD try to create namespaces:

1. Terraform creates namespace
2. ArgoCD tries to create namespace with CreateNamespace=true
3. Namespace already exists → sync drift

The Solution: Let ArgoCD Own Namespaces

WRONG - Terraform creates namespace:

resource "kubernetes_namespace" "arc_runners" {
  metadata {
    name = "arc-runners"
  }
}

resource "kubectl_manifest" "argocd_app" {
  yaml_body = yamlencode({
    # ...
    spec = {
      destination = {
        namespace = "arc-runners"  # Already exists
      }
      syncPolicy = {
        syncOptions = ["CreateNamespace=true"]  # Conflict!
      }
    }
  })
}

CORRECT - ArgoCD creates namespace:

resource "kubectl_manifest" "argocd_app" {
  yaml_body = yamlencode({
    apiVersion = "argoproj.io/​v1alpha1"
    kind       = "Application"
    metadata = {
      name      = "arc-runners"
      namespace = "argocd"
    }
    spec = {
      destination = {
        namespace = "arc-runners"  # ArgoCD will create this
      }
      syncPolicy = {
        automated = {
          prune    = true
          selfHeal = true
        }
        syncOptions = ["CreateNamespace=true"]  # ArgoCD manages it
      }
    }
  })
}

Exception: Namespace needs pre-created secrets

If you need to create secrets BEFORE the application deploys:

resource "kubernetes_namespace" "arc_runners" {
  metadata {
    name = "arc-runners"
  }
}

resource "kubernetes_secret" "github_token" {
  metadata {
    name      = "arc-org-github-secret"
    namespace = kubernetes_namespace.arc_runners.metadata[0].name
  }

  data = {
    github_token = var.github_token
  }

  type = "Opaque"
}

resource "kubectl_manifest" "argocd_app" {
  yaml_body = yamlencode({
    # ...
    spec = {
      destination = {
        namespace = "arc-runners"
      }
      syncPolicy = {
        syncOptions = []  # Do NOT include CreateNamespace - we created it
      }
    }
  })

  depends_on = [
    kubernetes_namespace.arc_runners,
    kubernetes_secret.github_token
  ]
}

Common Deployment Patterns

Pattern 1: ArgoCD Installation

module "argocd" {
  source = "./​modules/​argocd"

  kubeconfig_path     = module.cloudspace.kubeconfig_path
  github_token_secret = var.github_token
  bootstrap_repo_url  = "https://github.com/​Matchpoint-AI/​matchpoint-github-runners-helm"
}

Module responsibilities:

1. Install ArgoCD Helm chart
2. Wait for CRDs to register
3. Create bootstrap Application (App-of-Apps)

Pattern 2: Runner Scale Set Deployment

ArgoCD manages runner deployments via ApplicationSet:

# argocd/​applicationset.yaml
apiVersion: argoproj.io/​v1alpha1
kind: ApplicationSet
metadata:
  name: github-runners
spec:
  generators:
  - list:
      elements:
      - name: arc-beta-runners
        valuesFile: examples/​beta-runners-values.yaml
  template:
    metadata:
      name: '{{name}}'
    spec:
      source:
        repoURL: https://github.com/​Matchpoint-AI/​matchpoint-github-runners-helm
        targetRevision: main
        path: charts/​github-actions-runners
        helm:
          releaseName: '{{name}}'  # CRITICAL: Must match runnerScaleSetName
          valueFiles:
          - '../​../​{{valuesFile}}'

Troubleshooting

Error: "Provider produced inconsistent result"

Symptom:

Error: Provider produced inconsistent result after apply
The CRD "applications.argoproj.io" does not exist

Fix: Change from kubernetes_manifest to kubectl_manifest

Error: "Namespace already exists"

Symptom:

ArgoCD sync failed: namespace "arc-runners" already exists

Fix: Remove CreateNamespace=true from ArgoCD Application if Terraform created the namespace

Error: "Application CRD not found"

Symptom:

kubectl_manifest failed: no matches for kind "Application"

Fix: Add time_sleep resource after ArgoCD Helm release:

resource "time_sleep" "wait_for_crds" {
  depends_on      = [helm_release.argocd]
  create_duration = "30s"
}

Diagnostic Commands

# Check if ArgoCD CRDs are registered
kubectl api-resources | grep argoproj

# Verify ArgoCD installation
kubectl get pods -n argocd

# Check Application CRD definition
kubectl get crd applications.argoproj.io

# View terraform state for ArgoCD resources
cd terraform
terraform state list | grep argocd

# Check for orphaned kubernetes resources
terraform state list | grep kubernetes_

Best Practices

1. Always use kubectl_manifest for ArgoCD Applications - They depend on CRDs from the same apply
2. Add time_sleep after Helm releases that install CRDs - 30s is safe default
3. Let ArgoCD manage namespaces when possible - Reduces terraform/​ArgoCD conflicts
4. Use depends_on explicitly - Makes dependencies clear and prevents race conditions
5. Separate infrastructure from application config - Terraform for infra, ArgoCD for apps

Related Skills

• infrastructure-cd - CD workflows for terraform
• argocd-bootstrap - App-of-Apps pattern
• terraform-state-recovery - Cleaning orphaned state

Related Issues

• #121 - releaseName/​runnerScaleSetName mismatch
• #122 - ApplicationSet fix
• #112 - CI jobs stuck investigation

References

• kubectl provider docs
• Terraform time_sleep
• ArgoCD Application CRD