Deploy a Custom Ingress Gateway Using Cert-Manager

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.