ArgoCD

• Typical deployment into k8s
  
• GitOps
  
• Argo cd can be configure with Git repo for
  • manifests
  • helm
  • kustomize
• To configure argo with git we can execute
  • commands
  • manifest files (yaml)

Argo CD Tutorial

Argo CD Tutorial with a Kubernetes Manifest Example in a Git Repository

• official docs
• Git repo used in class

---

Step 1: Set Up the Git Repository

1. Create a Git Repository:
   Create a new Git repository on your preferred Git hosting service (e.g., GitHub, GitLab).
2. Add a Sample Kubernetes Manifest:
   Clone your repository and add a sample Kubernetes manifest. Below is an example of a guestbook application.

Directory Structure:
my-repo/
└── manifests/
├── deployment.yaml
├── service.yaml

deployment.yaml:
yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: guestbook
labels:
app: guestbook
spec:
replicas: 3
selector:
matchLabels:
app: guestbook
template:
metadata:
labels:
app: guestbook
spec:
containers:
- name: guestbook
image: redis:alpine
ports:
- containerPort: 6379

service.yaml:
yaml
apiVersion: v1
kind: Service
metadata:
name: guestbook
spec:
selector:
app: guestbook
ports:
- protocol: TCP
port: 80
targetPort: 6379
type: ClusterIP

1. Push the Files to Git:
   bash
git add .
git commit -m "Add guestbook Kubernetes manifests"
git push origin main

---

Step 2: Install Argo CD

Follow the installation steps provided in the main tutorial:
1. Create the namespace:
bash
kubectl create namespace argocd
2. Install Argo CD:
bash
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml
3. Port-forward the service to access the UI:
bash
kubectl port-forward svc/argocd-server -n argocd 8080:443

---

Step 3: Create the Argo CD Application

1. Login to Argo CD:
   Retrieve the admin password:
   bash
kubectl get secret argocd-initial-admin-secret -n argocd -o jsonpath="{.data.password}" | base64 -d
   Login via the CLI:
   bash
argocd login localhost:8080
2. Add Your Git Repository to Argo CD:
   Replace <GIT_REPO_URL> with the URL of your repository:
   bash
argocd repo add <GIT_REPO_URL>
3. Create an Argo CD Application:
   Run the following command to create an application in Argo CD:
   bash
argocd app create guestbook \
--repo <GIT_REPO_URL> \
--path manifests \
--dest-server https://kubernetes.default.svc \
--dest-namespace default

Example:
bash
argocd app create guestbook \
--repo https://github.com/your-username/my-repo.git \
--path manifests \
--dest-server https://kubernetes.default.svc \
--dest-namespace default

---

Step 4: Sync the Application

1. Sync the Application via CLI:
   bash
argocd app sync guestbook
2. Sync the Application via UI:
3. Access the Argo CD web UI at https://localhost:8080.
4. Login using the admin credentials.
5. Click on the guestbook application.
6. Click the “Sync” button to deploy the application.
7. Verify the Deployment:
   Check the resources in the Kubernetes cluster:
   bash
kubectl get all -n default

---

Step 5: Monitor and Manage the Application

1. Check Application Status:
   bash
argocd app get guestbook
2. View Logs:
   To view logs of a specific pod:
   bash
kubectl logs <POD_NAME> -n default
3. Update the Application:
4. Modify the manifests in the Git repository.
5. Commit and push the changes.
6. Argo CD will detect the changes and show the application as OutOfSync.
7. Sync Again:
   bash
argocd app sync guestbook

---

Step 6: Enable Automatic Sync (Optional)

To enable auto-sync for the guestbook application:

argocd app set guestbook --sync-policy automated

---

Step 7: Clean Up

To delete the application and resources:

argocd app delete guestbook

To uninstall Argo CD:

kubectl delete namespace argocd

Argo CD Tutorial with Helm Chart Deployment

Step 1: Set Up the Git Repository with Helm Charts

1. Create a Git Repository:
2. Create a new repository to store your Helm chart or use an existing one.
3. Add a Sample Helm Chart:
4. You can create a Helm chart using the helm create command or download an existing one.

Example directory structure for a Helm chart:
my-repo/
└── helm/
└── guestbook/
├── Chart.yaml
├── values.yaml
├── templates/
├── deployment.yaml
├── service.yaml

Chart.yaml:
yaml
apiVersion: v2
name: guestbook
description: A sample Helm chart for a Kubernetes application
version: 1.0.0
appVersion: 1.0.0

values.yaml:
yaml
replicas: 3
image:
repository: redis
tag: alpine
service:
type: ClusterIP
port: 6379

templates/deployment.yaml:
yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ .Chart.Name }}
labels:
app: {{ .Chart.Name }}
spec:
replicas: {{ .Values.replicas }}
selector:
matchLabels:
app: {{ .Chart.Name }}
template:
metadata:
labels:
app: {{ .Chart.Name }}
spec:
containers:
- name: {{ .Chart.Name }}
image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
ports:
- containerPort: {{ .Values.service.port }}

templates/service.yaml:
yaml
apiVersion: v1
kind: Service
metadata:
name: {{ .Chart.Name }}
spec:
type: {{ .Values.service.type }}
ports:
- port: 80
targetPort: {{ .Values.service.port }}
selector:
app: {{ .Chart.Name }}

1. Push the Chart to Git:
   bash
git add .
git commit -m "Add Helm chart for guestbook application"
git push origin main

---

Step 2: Install Argo CD

Follow the installation steps as described in the Argo CD installation tutorial. Ensure Argo CD is installed and running in your Kubernetes cluster.

---

Step 3: Deploy the Helm Chart Using Argo CD

1. Add Your Git Repository to Argo CD:
   bash
argocd repo add <GIT_REPO_URL>
2. Create an Argo CD Application for the Helm Chart:
   Replace <GIT_REPO_URL> and <APP_NAME> with your repository URL and application name.

bash
argocd app create guestbook-helm \
--repo <GIT_REPO_URL> \
--path helm/guestbook \
--dest-server https://kubernetes.default.svc \
--dest-namespace default \
--helm-set replicas=3 \
--helm-set image.repository=redis \
--helm-set image.tag=alpine

Example:
bash
argocd app create guestbook-helm \
--repo https://github.com/your-username/my-repo.git \
--path helm/guestbook \
--dest-server https://kubernetes.default.svc \
--dest-namespace default

1. Sync the Application:
   bash
argocd app sync guestbook-helm

---

Step 4: Use Helm Repository (Optional)

If you want to deploy a chart directly from a Helm repository (e.g., Bitnami charts), follow these steps:

1. Add the Helm Repository:
   bash
argocd repo add https://charts.bitnami.com/bitnami --type helm
2. Create an Application Using a Helm Chart:
   bash
argocd app create guestbook-helm \
--repo https://charts.bitnami.com/bitnami \
--helm-chart redis \
--revision 17.4.0 \
--dest-server https://kubernetes.default.svc \
--dest-namespace default \
--helm-set replicaCount=3
3. Sync the Application:
   bash
argocd app sync guestbook-helm

---

Step 5: Monitor and Manage the Application

1. Check Application Status:
   bash
argocd app get guestbook-helm
2. View Application Details in the Web UI:
3. Access the Argo CD web UI at https://localhost:8080.
4. Navigate to the guestbook-helm application to see deployment details, status, and logs.
5. Update the Helm Values:
   To update Helm values (e.g., change the number of replicas):
   bash
argocd app set guestbook-helm --helm-set replicas=5
argocd app sync guestbook-helm
6. Rollback to a Previous Version:
   bash
argocd app rollback guestbook-helm <REVISION_NUMBER>

---

Step 6: Enable Auto-Sync for Helm Applications

Enable auto-sync for the guestbook-helm application:

argocd app set guestbook-helm --sync-policy automated

---

Step 7: Clean Up

To delete the Helm application and resources:

argocd app delete guestbook-helm

To uninstall Argo CD:

kubectl delete namespace argocd

Well known k8s issues and how to resolve them

• k8s troubleshooting docs