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Deploying Applications

Purpose: For application developers, shows how to create an app repo, configure FluxCD, deploy pods, and verify traffic.

Outcome​

By the end of this tutorial you'll have a running application on an openCenter cluster, accessible over HTTPS through Gateway API, with FluxCD reconciling changes from your Git repository.

Prerequisites​

  • An openCenter cluster with FluxCD bootstrapped
  • kubectl configured with cluster access
  • A Git repository for your application (GitHub, GitLab, or Gitea)
  • The platform team has created a namespace for your application

Step 1 — Scaffold Your Application Repository​

Create a repository following the openCenter-customer-app-example pattern:

my-app/
├── kustomization.yaml
├── namespace.yaml
├── deployment.yaml
├── service.yaml
├── httproute.yaml
└── networkpolicy.yaml

Start with the root kustomization.yaml:

# kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  - namespace.yaml
  - deployment.yaml
  - service.yaml
  - httproute.yaml
  - networkpolicy.yaml

Step 2 — Define the Deployment and Service​

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
  namespace: my-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
        - name: my-app
          image: harbor.opencenter.example.com/customer-apps/my-app:1.0.0-abc1234
          ports:
            - containerPort: 8080
          resources:
            requests:
              cpu: 100m
              memory: 128Mi
            limits:
              cpu: 500m
              memory: 256Mi
          livenessProbe:
            httpGet:
              path: /healthz
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 10
          readinessProbe:
            httpGet:
              path: /readyz
              port: 8080
            initialDelaySeconds: 3
            periodSeconds: 5
      securityContext:
        runAsNonRoot: true
        seccompProfile:
          type: RuntimeDefault
---
# service.yaml
apiVersion: v1
kind: Service
metadata:
  name: my-app
  namespace: my-app
spec:
  selector:
    app: my-app
  ports:
    - port: 80
      targetPort: 8080
      protocol: TCP

Step 3 — Configure HTTPS Routing​

Create an HTTPRoute that routes traffic through the shared Gateway:

# httproute.yaml
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: my-app
  namespace: my-app
spec:
  parentRefs:
    - name: platform-gateway
      namespace: gateway-system
  hostnames:
    - "my-app.example.com"
  rules:
    - matches:
        - path:
            type: PathPrefix
            value: /
      backendRefs:
        - name: my-app
          port: 80

TLS is handled by the Gateway listener and cert-manager. You don't need to configure certificates in your HTTPRoute — the platform Gateway already has a wildcard or per-host certificate.

Step 4 — Request Platform Team Onboarding​

Push your repository to Git. Then ask the platform team to create the FluxCD resources in the cluster's GitOps repo:

# Platform team creates: services/sources/my-app.yaml
apiVersion: source.toolkit.fluxcd.io/v1
kind: GitRepository
metadata:
  name: my-app
  namespace: flux-system
spec:
  url: ssh://git@github.com/my-org/my-app.git
  ref:
    branch: main
  interval: 5m
  secretRef:
    name: my-app-deploy-key
---
# Platform team creates: services/fluxcd/my-app.yaml
apiVersion: kustomize.toolkit.fluxcd.io/v1
kind: Kustomization
metadata:
  name: my-app
  namespace: flux-system
spec:
  sourceRef:
    kind: GitRepository
    name: my-app
  path: ./
  interval: 10m
  prune: true
  targetNamespace: my-app

After the platform team commits these files, FluxCD picks up your application within the next reconciliation interval (default: 5 minutes).

Check Your Work​

Verify the deployment is running:

kubectl get pods -n my-app
# Expected: 2/2 Running

kubectl get httproute -n my-app
# Expected: my-app with parentRef platform-gateway

Test HTTPS access:

curl -s https://my-app.example.com/healthz
# Expected: 200 OK

Check FluxCD reconciliation status:

flux get kustomizations -n flux-system | grep my-app
# Expected: Applied revision: main@sha1:abc1234

Next Steps​