argocd-demo

A simple demo of ArgoCD

Setup of ArgoCD on a cluster

First we need to set up ArgoCD on the cluster. For this part we follow the instruction given by ArgoCD. After this step we have the ArgoCD controller installed along with the CRDs that ArgoCD defines.

Setup of a simple application

Next we deploy a simple application with ArgoCD. For this purpose we first create a new namespace for our application:

kubectl create ns awesome-gitops

Now we are ready to deploy the Application resource which ArgoCD needs to know the details about our application:

kubectl -n argocd apply -f ./application-simple.yml

If we check the ArgoCD web application, we see that the application is being deployed.

Make a change to the application

Lets make a change to the application's Deployment resource. We will upgrade to a new version of awesome-image and manually set a new title. The new Deployment ressource should look like this

apiVersion: apps/v1
kind: Deployment
metadata:
  name: awesome-app-deployment
  labels:
    app: awesome-app
spec:
  replicas: 3
  selector:
    matchLabels:
      component: awesome-app
  template:
    metadata:
      labels:
        component: awesome-app
    spec:
      serviceAccountName: awesome-app-sa
      containers:
        - name: awesome-app
          image: bespinian/awesome-image:2.0.0
          imagePullPolicy: Always
          env:
            - name: APP_TITLE
              value: "Something even awesomer!"
            - name: DB_HOST
              valueFrom:
                configMapKeyRef:
                  name: awesome-app-config
                  key: dbHost
            - name: APP_VERSION
              valueFrom:
                configMapKeyRef:
                  name: awesome-app-config
                  key: appVersion
          ports:
            - containerPort: 8080

When we commit and push this change to this repo, we see that ArgoCD applies the new state to the cluster.