In this article, I want to share with you my recent experience with GKE to deploy a CD tool like ArgoCD. I will use Terraform to deploy the GKE cluster and deploy my Helm chart within the newly created cluster.
Here's what it will look like:
Prerequisites
Terraform v1.0.0+
gcloud cli authenticated- gcloud plugin gke-gcloud-auth-plugin
kubectl binary
Service account with the required permissions (following Least Privilege principle) and its access key.
Setup
Firstly, we need to do is to add the Terraform providers for Helm and for our GKE cluster. Create the file providers.tf. Add these lines to specify where Kubernetes and Helm resources must apply:
# providers.tf
provider "kubernetes" {
host = "https://${data.google_container_cluster.my_cluster.endpoint}"
token = data.google_client_config.default.access_token
cluster_ca_certificate = base64decode(data.google_container_cluster.my_cluster.master_auth[0].cluster_ca_certificate)
}
provider "helm" {
kubernetes = {
host = "https://${data.google_container_cluster.my_cluster.endpoint}"
token = data.google_client_config.default.access_token
cluster_ca_certificate = base64decode(data.google_container_cluster.my_cluster.master_auth[0].cluster_ca_certificate)
}
}
As you can see we use variables referenced as data sources. So let's create the file data.tf. Then add the data sources.
# data.tf
data "google_container_cluster" "my_cluster" {
name = "autopilot-cluster-1"
location = var.region
project = var.project_id
}
data "google_client_config" "default" {}
The client config fetch a short-live token in order to access your cluster.
Then we create the variables.tf.
# variables.tf
variable "project_id" {
type = string
}
variable "region" {
type = string
}
Terraform state
Terraform is a stateful language. It means that it stores the state of each services deployed. Every time you run terraform plan/apply it will check the state file to determine which resource needs to be deployed or edited. We have multiple ways to store it. In my case, I chose to store it on Gitlab. It is easy to setup you just need your gitlab personal token with scope set to api. Create a backend.tf file.
# backend.tf
terraform {
backend "http" {
}
}
When you run your terraform init command, you will need to specify the backend config. Gitlab gives you the template command :
export GITLAB_ACCESS_TOKEN=<YOUR-ACCESS-TOKEN>
export TF_STATE_NAME=argo-state
terraform init \
-backend-config="address=https://gitlab.example.com/api/v4/projects/<id>/terraform/state/$TF_STATE_NAME" \
-backend-config="lock_address=https://gitlab.example.com/api/v4/projects/<id>/terraform/state/$TF_STATE_NAME/lock" \
-backend-config="unlock_address=https://gitlab.example.com/api/v4/projects/<id>/terraform/state/$TF_STATE_NAME/lock" \
-backend-config="username=<your-user>" \
-backend-config="password=$GITLAB_ACCESS_TOKEN" \
-backend-config="lock_method=POST" \
-backend-config="unlock_method=DELETE" \
-backend-config="retry_wait_min=5"
Part 1: Helm chart
In the first part, we will focus on ArgoCD deployment. I am going to use the official chart. Let's create our first file main.tf. I will put all the Kubernetes resources in it. Declare the following resource:
# main.tf
resource "helm_release" "argocd" {
name = "argocd"
repository = "https://argoproj.github.io/argo-helm"
chart = "argo-cd"
namespace = kubernetes_namespace_v1.argocd_ns.metadata[0].name
create_namespace = false
version = "9.4.6"
values = [ file("values/argocd-values.yaml")]
depends_on = [ kubernetes_manifest.argocd_backend_config ]
}
You can either set 'create_namespace = true' or create the namespace using a kubernetes resource like this:
resource "kubernetes_namespace_v1" "argocd_ns" {
metadata {
name = "argocd"
labels = {
"name" = "argocd"
}
}
}
Now, let's create the values file. It contains the basic setup of the deployment. Inside you can configure resource limitation that can be useful considering the billing method in use by GKE. Here is the values file I use:
# argocd-values.yaml
global:
domain: argo.example.com
nodeSelector:
cloud.google.com/gke-spot: "true"
tolerations:
- key: "cloud.google.com/gke-spot"
operator: "Equal"
value: "true"
effect: "NoSchedule"
server:
# Run multiple replicas for high availability
replicas: 1
service:
type: NodePort
annotations:
cloud.google.com/backend-config: '{"default": "argocd-backend-config"}'
# Resource limits prevent runaway memory consumption
resources:
limits:
cpu: 500m
memory: 512Mi
requests:
cpu: 100m
memory: 256Mi
# Enable metrics for Prometheus scraping
metrics:
enabled: true
serviceMonitor:
enabled: true
controller:
# Controller handles sync operations - scale for large deployments
replicas: 1
resources:
limits:
cpu: 1000m
memory: 1Gi
requests:
cpu: 250m
memory: 512Mi
repoServer:
# Repo server renders Helm templates - critical for performance
replicas: 1
resources:
limits:
cpu: 1000m
memory: 1Gi
requests:
cpu: 250m
memory: 512Mi
configs:
params:
# Disable TLS for internal communication (use ingress for external TLS)
server.insecure: true
Part 2: Networking
Now that we have our ArgoCD ready, we need to expose the argo-server service to ensure its access from outside. For that we will create an ingress that trigger the creation of an external application load balancer (L7) by GKE. We need to reserve a static external IP address for the ALB. For our ArgoCD to be secured, we let GCP generate a SSL certificate for our domain name using ManagedCertificate.
Let's start with the ingress config:
# main.tf
resource "kubernetes_ingress_v1" "argo_ingress" {
metadata {
name = "argocd-ingress"
namespace = kubernetes_namespace_v1.argocd_ns.metadata[0].name
annotations = {
"kubernetes.io/ingress.class" = "gce"
"kubernetes.io/ingress.global-static-ip-name" = "argocd-static-ip"
"networking.gke.io/managed-certificates" = "argo-cert"
"cloud.google.com/backend-config" = jsonencode({ "default" = "argocd-backend-config" })
}
}
spec {
rule {
host = "argo.example.com"
http {
path {
path = "/"
path_type = "Prefix"
backend {
service {
name = "argocd-server"
port {
number = 80
}
}
}
}
}
}
}
}
I created a new file for the load balancer resources named lb-gke.tf. Inside, you reserve the IP address for the ALB. Then you create the backend config that is required for the ALB to do health check on your service. The last thing is the cert manager to provide an SSL certificate.
# lb-gke.tf
resource "google_compute_global_address" "argocd_static_ip" {
name = "argocd-static-ip"
project = var.project_id
}
resource "kubernetes_manifest" "argocd_backend_config" {
manifest = {
apiVersion = "cloud.google.com/v1"
kind = "BackendConfig"
metadata = {
name = "argocd-backend-config"
namespace = "argocd"
}
spec = {
healthCheck = {
checkIntervalSec = 30
timeoutSec = 5
healthyThreshold = 1
unhealthyThreshold = 2
type = "HTTP"
requestPath = "/healthz"
port = 8080
}
}
}
depends_on = [ kubernetes_namespace_v1.argocd_ns ]
}
resource "kubernetes_manifest" "argocd_managed_cert" {
manifest = {
apiVersion = "networking.gke.io/v1"
kind = "ManagedCertificate"
metadata = {
name = "argo-cert"
namespace = kubernetes_namespace_v1.argocd_ns.metadata[0].name
}
spec = {
domains = ["argo.example.com"]
}
}
}
Part 3: Deploy your ArgoCD
We are done with the config. Now it is time to deploy !
Create the file outputs.tf and add these lines :
output "argocd_lb_ip" {
value = google_compute_global_address.argocd_static_ip.address
}
When Terraform will be done applying, it will output the reserved IP for your ALB.
Run your init command then you can run terraform plan command to ensure it will deploy the right resources. Finally, run terraform apply.
There you go you have your ArgoCD deployed !
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