K
Q

Migrate to istio from nginx ingress

5/15/2018

I've simple single page golang web application, I'm trying to migrate to istio.

My prod setup (via nginx ingress):

---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: goapp
  annotations:
     kubernetes.io/ingress.class: nginx
     kubernetes.io/tls-acme: "true"
spec:
  tls:
  - hosts:
    - mycustomapp.mycustomapp.com
    secretName: go-tls
  rules:
  - host: mycustomapp.mycustomapp.com
    http:
      paths:
      - path: /
        backend:
          serviceName: mycustomapp
          servicePort: 80

And I'm trying to build at least http configuration for istio

    apiVersion: extensions/v1beta1
    kind: Ingress
    metadata:
      name: goapp
      annotations:
         kubernetes.io/ingress.class: istio
    spec:
      rules:
      - host: mycustomapp.mycustomapp.com
        http:
          paths:
          - path: /
            backend:
              serviceName: mycustomapp
              servicePort: 80

But I always get 404 from istio lb on clean cluster with istio 0.7.1 only installed. Samples like bookinfo and httpbin works well

Application yaml:

   kind: Deployment
    apiVersion: apps/v1
    metadata:
      labels:
        k8s-app: mycustomapp
      name: mycustomapp
    spec:
      replicas: 1
      selector:
        matchLabels:
          k8s-app: mycustomapp
      template:
        metadata:
          labels:
            k8s-app: mycustomapp
        spec:
          containers:
          - name: mycustomapp
            image: xxxx.azurecr.io/mycustomapp:999
            ports:
            - containerPort: 80
              protocol: TCP
          imagePullSecrets:
          - name: xxxx
          serviceAccountName: mycustomapp
    ---
    kind: Service
    apiVersion: v1
    metadata:
      annotations:
        prometheus.io/scrape: 'true'
      labels:
        k8s-app: mycustomapp
      name: mycustomapp
    spec:
      type: ClusterIP
      ports:
        - port: 80
          targetPort: 80
      selector:
        k8s-app: mycustomapp
-- J. Doe
istio
kubernetes
kubernetes-ingress

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1 Answer

5/18/2018

To get rid of the 404 error in your case, it should be enough to add the correct port name to the service and deployment YAML files, and add istio sidecar to the deployment YAML file. Then you should redeploy all changed files.

Perhaps you may need to add label app: mycustomapp to the service and deployment, but I'm not sure is it required or optional.

Here is example of the service.yaml file with the correct port name (more about the port names you can read here):

kind: Service
apiVersion: v1
metadata:
  annotations:
    prometheus.io/scrape: 'true'
  labels:
    app: mycustomapp
    k8s-app: mycustomapp
  name: mycustomapp
spec:
  type: ClusterIP
  ports:
    - name: http-80
      port: 80
      targetPort: 80
  selector:
    k8s-app: mycustomapp

Ensure you have also the correct port name in your deployment file.

You can add the istio sidecar to the container manually, following these steps:

  1. download and unpack latest istio release, suitable for your OS from https://github.com/istio/istio/releases

  2. Change directory to istio package. For example, if the package is istio-0.7

    cd istio-0.7

  3. Create inject config:

    kubectl create -f install/kubernetes/istio-sidecar-injector-configmap-release.yaml --dry-run -o=jsonpath='{.data.config}' > inject-config.yaml

  4. Create mesh config:

    kubectl -n istio-system get configmap istio -o=jsonpath='{.data.mesh}' > mesh-config.yaml

  5. Add istio sidecar container to your deployment:

    bin/istioctl kube-inject \ --injectConfigFile inject-config.yaml \ --meshConfigFile mesh-config.yaml \ --filename path/to/original/deployment.yaml \ --output deployment-injected.yaml

  6. Deploy new deployment: kubectl apply -f deployment-injected.yaml

If you want to have automatic sidecar injection, follow this manual.

You can check if the sidecar has been injected into the deployment:

$ kubectl get deployment mycustomapp -o wide
NAME          DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE       CONTAINERS                IMAGES                                    SELECTOR
mycustomapp   1         1         1            1           3h        mycustomapp,istio-proxy   nginx:1.7.9,docker.io/istio/proxy:0.7.1   k8s-app=mycustomapp
-- VAS
Source: StackOverflow