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Deploying an App ​

This guide explains how to add a new application to your cluster and have it automatically deployed by ArgoCD whenever you push to your infra repo.

How it works (GitOps loop) ​

You push to infra/       GitHub fires webhook      ArgoCD syncs cluster
kubernetes/apps/myapp/ ──────────────────────────▶ argocd.kevindb.dev ──▶ k8s applies
  1. Create app manifests in infra/kubernetes/apps/<appname>/
  2. Create an ArgoCD Application in infra/kubernetes/argocd/apps/<appname>.yaml
  3. Apply the ArgoCD Application once — from then on, git push = deploy

Step 1 — Create your app manifests ​

Create a directory in your infra repo:

infra/
  kubernetes/
    apps/
      myapp/
        deployment.yaml
        service.yaml
        ingress.yaml

deployment.yaml ​

yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
  namespace: apps
spec:
  replicas: 2
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
        - name: myapp
          image: myimage:latest
          ports:
            - containerPort: 80
          resources:
            requests:
              cpu: 50m
              memory: 64Mi
            limits:
              cpu: 200m
              memory: 128Mi

service.yaml ​

yaml
apiVersion: v1
kind: Service
metadata:
  name: myapp
  namespace: apps
spec:
  selector:
    app: myapp
  ports:
    - port: 80
      targetPort: 80

ingress.yaml ​

yaml
# TLS certificate (cert-manager → Let's Encrypt)
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: myapp-tls
  namespace: apps
spec:
  secretName: myapp-tls
  issuerRef:
    name: letsencrypt-production
    kind: ClusterIssuer
  dnsNames:
    - myapp.kevindb.dev
---
# Traefik IngressRoute
apiVersion: traefik.io/v1alpha1
kind: IngressRoute
metadata:
  name: myapp
  namespace: apps
spec:
  entryPoints:
    - websecure
  routes:
    - match: Host(`myapp.kevindb.dev`)
      kind: Rule
      services:
        - name: myapp
          port: 80
  tls:
    secretName: myapp-tls

Replace myapp.kevindb.dev with your actual subdomain.

Step 2 — Add a DNS record ​

Point your subdomain to the cluster's external IP (same IP as all other apps):

bash
kubectl --context k3s-infra get svc -n ingress traefik \
  -o jsonpath='{.status.loadBalancer.ingress[0].ip}'

Add an A record in your DNS provider:

TypeNameValue
Amyapp<traefik-ip>

Step 3 — Create the ArgoCD Application ​

Create infra/kubernetes/argocd/apps/myapp.yaml:

yaml
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: myapp
  namespace: argocd
  finalizers:
    - resources-finalizer.argocd.argoproj.io
spec:
  project: default

  source:
    repoURL: git@github.com:KevinDeBenedetti/infra.git
    targetRevision: main
    path: kubernetes/apps/myapp

  destination:
    server: https://kubernetes.default.svc
    namespace: apps

  syncPolicy:
    automated:
      prune: true      # remove resources deleted from Git
      selfHeal: true   # revert manual kubectl changes
    syncOptions:
      - CreateNamespace=true
      - ServerSideApply=true

repoURL must use the SSH format (git@github.com:...) to match the deploy key secret.

Step 4 — Apply and push ​

bash
# Register the ArgoCD Application in the cluster
kubectl --context k3s-infra apply -f kubernetes/argocd/apps/myapp.yaml

# Commit and push all manifests
git add kubernetes/apps/myapp/ kubernetes/argocd/apps/myapp.yaml
git commit -m "feat: add myapp"
git push

ArgoCD detects the push (via webhook) and syncs within seconds.

Step 5 — Verify ​

bash
# Check ArgoCD sync status
kubectl --context k3s-infra get application myapp -n argocd

# Check pods
kubectl --context k3s-infra get pods -n apps

# Check certificate
kubectl --context k3s-infra get certificate myapp-tls -n apps

Or open the ArgoCD UI: https://argocd.kevindb.dev

Day-to-day: updating an app ​

After initial setup, deploying a change is just:

bash
# Edit any manifest — e.g. bump the image tag
vim infra/kubernetes/apps/myapp/deployment.yaml

git add -A && git commit -m "chore: bump myapp to v1.2.3" && git push

ArgoCD auto-syncs. No kubectl apply needed.

Removing an app ​

bash
# Delete the ArgoCD Application (triggers prune → removes cluster resources)
kubectl --context k3s-infra delete application myapp -n argocd

# Remove the manifests from git
rm -rf kubernetes/apps/myapp/ kubernetes/argocd/apps/myapp.yaml
git add -A && git commit -m "chore: remove myapp" && git push

Checklist ​

  • [ ] DNS A record pointing to Traefik IP
  • [ ] kubernetes/apps/myapp/ directory with deployment, service, ingress
  • [ ] kubernetes/argocd/apps/myapp.yaml with SSH repoURL
  • [ ] kubectl apply -f kubernetes/argocd/apps/myapp.yaml (once)
  • [ ] git push — ArgoCD handles the rest

See also ​