# With Kustomize > Use the release file as a Kustomize base, and patch the namespace, message, Service and path prefix without Helm. Kustomize is built into `kubectl`. Use the [release file](https://paulbouwer.github.io/hello-kubernetes/docs/deploy/kubectl.md) as a base, and patch what you need. You don’t need Helm. | Needs | Installs into | You get | | - | - | - | | `kubectl` and a cluster | the namespace in your `kustomization.yaml` | the app with your changes | Each example is a folder with a `kustomization.yaml`. Pin the release file to a version, so the base doesn’t change under you. ## A namespace, a message and ClusterIP *File: kustomization.yaml* ```yaml apiVersion: kustomize.config.k8s.io/v1beta1 kind: Kustomization namespace: hello resources: - namespace.yaml - https://github.com/paulbouwer/hello-kubernetes/releases/download/v1.11.0/hello-kubernetes.yaml patches: - target: { kind: Service, name: hello-kubernetes-demo } patch: |- - op: replace path: /spec/type value: ClusterIP - target: { kind: Deployment, name: hello-kubernetes-demo } patch: |- - op: replace path: /spec/replicas value: 3 - op: add path: /spec/template/spec/containers/0/env/- value: { name: MESSAGE, value: "Deployed with Kustomize" } ``` *File: namespace.yaml* ```yaml apiVersion: v1 kind: Namespace metadata: name: hello ``` Apply it: ```bash kubectl apply -k . kubectl rollout status deployment/hello-kubernetes-demo --namespace hello ``` `op: add` with `env/-` adds to the end of the list. The release file already sets `KUBERNETES_NAMESPACE`, `KUBERNETES_POD_NAME`, `KUBERNETES_NODE_NAME` and `CONTAINER_IMAGE`. To change one of those, use `op: replace` on its position instead, or a strategic merge patch. ## A load balancer on port 8080 On k3s, k3d and Rancher Desktop, the built-in Traefik already uses port 80. Keep the `LoadBalancer` Service, and move it to port 8080: *File: kustomization.yaml* ```yaml apiVersion: kustomize.config.k8s.io/v1beta1 kind: Kustomization resources: - https://github.com/paulbouwer/hello-kubernetes/releases/download/v1.11.0/hello-kubernetes.yaml patches: - target: { kind: Service, name: hello-kubernetes-demo } patch: |- - op: replace path: /spec/ports/0/port value: 8080 ``` Apply it with `kubectl apply -k .`. `kubectl get service hello-kubernetes-demo` then shows an `EXTERNAL-IP`, and the app is at `http://:8080/`. With k3d, create the cluster with `-p "8080:8080@loadbalancer"`, and open `http://localhost:8080/`. ## An Ingress The release file has no Ingress. Add your own, and patch the app to serve under the prefix. This passes the prefix on, as `rewritePath: false` does in the chart, so the Ingress needs no annotations. The same pattern adds an `HTTPRoute` instead. *File: ingress.yaml* ```yaml apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: hello-kubernetes-demo spec: ingressClassName: traefik # or nginx, which also needs a host: below rules: - http: paths: - path: /app/hello pathType: Prefix backend: service: name: hello-kubernetes-demo port: number: 80 ``` *File: kustomization.yaml* ```yaml apiVersion: kustomize.config.k8s.io/v1beta1 kind: Kustomization namespace: hello resources: - namespace.yaml - https://github.com/paulbouwer/hello-kubernetes/releases/download/v1.11.0/hello-kubernetes.yaml - ingress.yaml patches: - target: { kind: Service, name: hello-kubernetes-demo } patch: |- - op: replace path: /spec/type value: ClusterIP - target: { kind: Deployment, name: hello-kubernetes-demo } patch: |- - op: add path: /spec/template/spec/containers/0/env/- value: { name: HANDLER_PATH_PREFIX, value: /app/hello } - op: add path: /spec/template/spec/containers/0/env/- value: { name: RENDER_PATH_PREFIX, value: /app/hello } - op: replace path: /spec/template/spec/containers/0/livenessProbe/httpGet/path value: /app/hello/ - op: replace path: /spec/template/spec/containers/0/readinessProbe/httpGet/path value: /app/hello/ ``` Use the same `namespace.yaml` as the first example. Apply it with `kubectl apply -k .`, and open `http:///app/hello/`. ## What each chart value changes To make a change that the chart has a value for, change the YAML like this: | Chart value | What it changes in the YAML | | - | - | | `message` | Adds the `MESSAGE` env var to the container | | `pathPrefix` | Sets `RENDER_PATH_PREFIX`; the path on the Ingress or HTTPRoute | | `rewritePath: false` | Also sets `HANDLER_PATH_PREFIX` to `pathPrefix`; the probes use `/` | | `rewritePath: true` | Sets `HANDLER_PATH_PREFIX` to `""`; the HTTPRoute gets a `URLRewrite` filter; an Ingress needs your controller’s annotation | | `service.type`, `service.port` | The Service `spec.type` and port | | `ingress.*` | Creates an Ingress, with the class, host, TLS and annotations | | `httpRoute.*` | Creates an HTTPRoute, with the parent refs and host names | | `deployment.replicaCount` | The Deployment `spec.replicas` | | `deployment.container.image.*` | The container `image` and `imagePullPolicy`, and the `CONTAINER_IMAGE` env var | | `deployment.container.port` | The `containerPort`, the probes’ port, and a `PORT` env var when it isn’t `8080` | | `deployment.container.securityContext` | The container `securityContext` | | `deployment.podSecurityContext` | The pod `securityContext` | | `deployment.resources`, `nodeSelector`, `tolerations`, `affinity` | Copied into the pod spec as they are | The root filesystem is read-only, so the Deployment mounts an `emptyDir` at `/tmp`. Keep it if you change the security settings. The container also has a `preStop` sleep of 5 seconds, so that an upgrade doesn’t drop requests while the pods are replaced. ## Verify ```bash kubectl port-forward service/hello-kubernetes-demo 8080:80 --namespace hello ``` Open `http://localhost:8080/`. In the first example, you see **Deployed with Kustomize**, from one of 3 pods. ## Upgrade Change the version in the release file’s URL, and apply again with `kubectl apply -k .`. Your patches apply to the new base. ## Uninstall ```bash kubectl delete -k . ``` This also deletes the namespace, when the folder has `namespace.yaml`. ## Requirements - Kubernetes 1.35 or newer, and the `kubectl` that matches it. CI tests 1.35 and the current release, on kind and k3d. - `linux/amd64` or `linux/arm64` nodes.