Run ArgoCD with Istio Service Mesh in a Kubernetes Cluster


It’s been quite a while since I installed Flux CD V2 in my garage Kubernetes lab, as there’s a lot of debate going on between Flux and ArgoCD I decided to give ArgoCD a go. The other reason to try ArgoCD is that it supports Jsonnet.

By default installation, ArgoCD will use self-signed TLS certificate and enforce TLS connection, which means users get to see the security warning and have to trust the certificate to continue. Naturally with Istio handles ingress and TLS termination, I would like to enable Istio sidecar for ArgoCD and run it in HTTP mode.

Here are the steps to configure and install ArgoCD along side with Istio:

Enalbe Istio Sidecar

I choose to enable automatic Istio sidecar injection for ArgoCD’s namespace.

# create the namespace, by default it's argocd
kubectl create namespace argocd
# turn on istio injection
kubectl label namespace argocd istio-injection=enabled

Install ArgoCD the Normal Way

kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

Disable TLS for argocd-server Deployment

This can be done before or after the deployment being applied to the cluster in the above step, eg. edit the install.yaml before the apply command or use kubectl edit deployment command afterwards. It may probably be easier if using Helm for this tweak.

# kubectl edit deployment argocd-server
# and add --insecure argument
...
      containers:
      - command:
        - argocd-server
      - args:
        - --insecure
...
# then save and exit. A new pod with --insecure will start and replace the old one

Sample Gateway Schema

apiVersion: networking.istio.io/v1beta1
kind: Gateway
metadata:
  name: argocd-gateway
spec:
  selector:
    istio: ingressgateway
  servers:
    - hosts:
        - argo.example.com
      port:
        name: https
        number: 443
        protocol: HTTPS
      tls:
        mode: SIMPLE
        # argo-cert is a tls secret in istio-system namespace, containing a valid TLS cert for the domain name argo.example.com
        credentialName: argo-cert
    - hosts:
        - argo.example.com
      port:
        name: http
        number: 80
        protocol: HTTP
      tls:
        httpsRedirect: true

I use cert-manager and let’s encrypt to provision free TLS certificates for my personal projects. For more info please see this.

Sample VirtualService Schema

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: argocd
spec:
  gateways:
    - argocd-gateway
  hosts:
    - argo.example.com
  http:
    - route:
      - destination:
          host: argocd-server
          port:
            number: 80

If the DNS is already working and pointing to the Istio ingress gateway, I can see ArgoCD in my browser with a valid TLS certificate.

🙂


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