Home

Appearance

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
apps/myapp/ ─────────────────────────────────────▶ argocd.example.com ──▶ k8s applies
  1. Create app manifests in infra/apps/<appname>/
  2. ArgoCD ApplicationSets auto-discover the new app directory
  3. git push = deploy — no manual kubectl apply needed

Step 1 — Create your app manifests ​

Create a directory in your infra repo:

infra/
  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 via DNS-01/Cloudflare)
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
  annotations:
    # external-dns: automatically creates/updates the A record in Cloudflare
    external-dns.alpha.kubernetes.io/hostname: myapp.kevindb.dev
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 — ArgoCD auto-discovers via ApplicationSets ​

ArgoCD uses ApplicationSets with a Git directory generator that automatically creates an Application for every subdirectory in apps/. No manual Application manifest is needed.

The ApplicationSet is defined in infra/argocd/applicationsets/apps.yaml:

yaml
apiVersion: argoproj.io/v1alpha1
kind: ApplicationSet
metadata:
  name: apps
  namespace: argocd
spec:
  generators:
    - git:
        repoURL: git@github.com:KevinDeBenedetti/infra.git
        revision: main
        directories:
          - path: apps/*
  template:
    metadata:
      name: "{{path.basename}}"
    spec:
      project: apps
      source:
        repoURL: git@github.com:KevinDeBenedetti/infra.git
        targetRevision: main
        path: "{{path}}"
      destination:
        server: https://kubernetes.default.svc
        namespace: apps
      syncPolicy:
        automated:
          prune: true
          selfHeal: true

Add a new directory under apps/ and push — ArgoCD handles the rest.

Step 3 — Push ​

bash
# Commit and push all manifests
git add apps/myapp/
git commit -m "feat: add myapp"
git push

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

Step 4 — Verify ​

bash
# Check DNS was created in Cloudflare (within ~1 min)
dig myapp.kevindb.dev +short

# 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 (DNS-01 — works even before DNS resolves)
kubectl --context k3s-infra get certificate myapp-tls -n apps

# Check external-dns logs
make external-dns-logs

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/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
# Remove the app directory from git — ArgoCD prunes cluster resources
rm -rf apps/myapp/
git add -A && git commit -m "chore: remove myapp" && git push

Checklist ​

  • [ ] external-dns.alpha.kubernetes.io/hostname annotation on IngressRoute (DNS A record auto-created)
  • [ ] apps/myapp/ directory with deployment, service, ingress
  • [ ] git push — ApplicationSets auto-discover and ArgoCD handles the rest

See also ​