days to Istio 1.5

Deploy a Custom Ingress Gateway Using Cert-Manager

Custom ingress gateway

This post provides instructions to manually create a custom ingress gateway with automatic provisioning of certificates based on cert-manager.

The creation of custom ingress gateway could be used in order to have different loadbalancer in order to isolate traffic.

Before you begin

  • Setup Istio by following the instructions in the Installation guide.
  • Setup cert-manager with helm chart
  • We will use demo.mydemo.com for our example, it must be resolved with your DNS

Configuring the custom ingress gateway

  1. Check if cert-manager was installed using Helm with the following command:

    $ helm ls
    

    The output should be similar to the example below and show cert-manager with a STATUS of DEPLOYED:

    NAME   REVISION UPDATED                  STATUS   CHART                     APP VERSION   NAMESPACE
    istio     1     Thu Oct 11 13:34:24 2018 DEPLOYED istio-1.0.X               1.0.X         istio-system
    cert      1     Wed Oct 24 14:08:36 2018 DEPLOYED cert-manager-v0.6.0-dev.2 v0.6.0-dev.2  istio-system
    
  2. To create the cluster’s issuer, apply the following configuration:

    apiVersion: certmanager.k8s.io/v1alpha1
    kind: ClusterIssuer
    metadata:
      name: letsencrypt-demo
      namespace: kube-system
    spec:
      acme:
        # The ACME server URL
        server: https://acme-v02.api.letsencrypt.org/directory
        # Email address used for ACME registration
        email: <REDACTED>
        # Name of a secret used to store the ACME account private key
        privateKeySecretRef:
          name: letsencrypt-demo
        dns01:
          # Here we define a list of DNS-01 providers that can solve DNS challenges
          providers:
          - name: your-dns
            route53:
              accessKeyID: <REDACTED>
              region: eu-central-1
              secretAccessKeySecretRef:
                name: prod-route53-credentials-secret
                key: secret-access-key
    
  3. If you use the route53 provider, you must provide a secret to perform DNS ACME Validation. To create the secret, apply the following configuration file:

    apiVersion: v1
    kind: Secret
    metadata:
      name: prod-route53-credentials-secret
    type: Opaque
    data:
      secret-access-key: <REDACTED BASE64>
    
  4. Create your own certificate:

    apiVersion: certmanager.k8s.io/v1alpha1
    kind: Certificate
    metadata:
      name: demo-certificate
      namespace: istio-system
    spec:
      acme:
        config:
        - dns01:
            provider: your-dns
          domains:
          - '*.mydemo.com'
      commonName: '*.mydemo.com'
      dnsNames:
      - '*.mydemo.com'
      issuerRef:
        kind: ClusterIssuer
        name: letsencrypt-demo
      secretName: istio-customingressgateway-certs
    

    Make a note of the value of secretName since a future step requires it.

  5. To scale automatically, declare a new horizontal pod autoscaler with the following configuration:

    apiVersion: autoscaling/v1
    kind: HorizontalPodAutoscaler
    metadata:
      name: my-ingressgateway
      namespace: istio-system
    spec:
      maxReplicas: 5
      minReplicas: 1
      scaleTargetRef:
        apiVersion: apps/v1beta1
        kind: Deployment
        name: my-ingressgateway
      targetCPUUtilizationPercentage: 80
    status:
      currentCPUUtilizationPercentage: 0
      currentReplicas: 1
      desiredReplicas: 1
    
  6. Apply your deployment with declaration provided in the yaml definition

  7. Create your service:

    apiVersion: v1
    kind: Service
    metadata:
      name: my-ingressgateway
      annotations:
        service.beta.kubernetes.io/aws-load-balancer-type: nlb
      labels:
        app: my-ingressgateway
        istio: my-ingressgateway
    spec:
      type: LoadBalancer
      selector:
        app: my-ingressgateway
        istio: my-ingressgateway
      ports:
        -
          name: http2
          nodePort: 32380
          port: 80
          targetPort: 80
        -
          name: https
          nodePort: 32390
          port: 443
        -
          name: tcp
          nodePort: 32400
          port: 31400
    
  8. Create your Istio custom gateway configuration object:

    apiVersion: networking.istio.io/v1alpha3
    kind: Gateway
    metadata:
      annotations:
      name: istio-custom-gateway
      namespace: default
    spec:
      selector:
        istio: my-ingressgateway
      servers:
      - hosts:
        - '*.mydemo.com'
        port:
          name: http
          number: 80
          protocol: HTTP
        tls:
          httpsRedirect: true
      - hosts:
        - '*.mydemo.com'
        port:
          name: https
          number: 443
          protocol: HTTPS
        tls:
          mode: SIMPLE
          privateKey: /etc/istio/ingressgateway-certs/tls.key
          serverCertificate: /etc/istio/ingressgateway-certs/tls.crt
    
  9. Link your istio-custom-gateway with your VirtualService:

    apiVersion: networking.istio.io/v1alpha3
    kind: VirtualService
    metadata:
      name: my-virtualservice
    spec:
      hosts:
      - "demo.mydemo.com"
      gateways:
      - istio-custom-gateway
      http:
      - route:
        - destination:
            host: my-demoapp
    
  10. Correct certificate is returned by the server and it is successfully verified (SSL certificate verify ok is printed):

    $ curl -v `https://demo.mydemo.com`
    Server certificate:
      SSL certificate verify ok.
    

Congratulations! You can now use your custom istio-custom-gateway gateway configuration object.

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