Ingress Controller

Learn about installing Istio ingress controller in a Kubernetes cluster running Seldon Core 2.

An ingress controller functions as a reverse proxy and load balancer, implementing a Kubernetes Ingress. It adds an abstraction layer for traffic routing by receiving traffic from outside the Kubernetes platform and load balancing it to Pods running within the Kubernetes cluster.

Seldon Core 2 works seamlessly with any service mesh or ingress controller, offering flexibility in your deployment setup. This guide provides detailed instructions for installing and configuring Istio with Seldon Core 2.

Istio

Istio implements the Kubernetes ingress resource to expose a service and make it accessible from outside the cluster. You can install Istio in either a self-hosted Kubernetes cluster or a managed Kubernetes service provided by a cloud provider that is running the Seldon Core 2.

Prerequisites

• Install Seldon Core 2.

• Ensure that you install a version of Istio that is compatible with your Kubernetes cluster version. For detailed information on supported versions, refer to the Istio Compatibility Matrix.

Installing Istio ingress controller

Installing Istio ingress controller in a Kubernetes cluster running Seldon Core 2 involves these tasks:

1. Install Istio

2. Install Istio Ingress Gateway

3. Expose Seldon mesh service

Install Istio

1. Add the Istio Helm charts repository and update it:

   helm repo add istio https://istio-release.storage.googleapis.com/charts
   helm repo update

2. Create the istio-system namespace where Istio components are installed:

   kubectl create namespace istio-system

3. Install the base component:

   helm install istio-base istio/base -n istio-system

4. Install Istiod, the Istio control plane:

   helm install istiod istio/istiod -n istio-system --wait

Install Istio Ingress Gateway

1. Install Istio Ingress Gateway:

   helm install istio-ingressgateway istio/gateway -n istio-system

2. Verify that Istio Ingress Gateway is installed:

   kubectl get svc istio-ingressgateway -n istio-system

   This should return details of the Istio Ingress Gateway, including the external IP address.

3. Verify that all Istio Pods are running:

   kubectl get pods -n istio-system

   The output is similar to:

   NAME                          READY   STATUS    RESTARTS   AGE
   istiod-xxxxxxx-xxxxx          1/1     Running   0          2m
   istio-ingressgateway-xxxxx    1/1     Running   0          2m

4. Inject Envoy sidecars into application Pods in the namespace seldon-mesh:

   kubectl label namespace seldon-mesh istio-injection=enabled

5. Verify that the injection happens to the Pods in the namespace seldon-mesh:

   kubectl get namespace seldon-mesh --show-labels

6. Find the IP address of the Seldon Core 2 instance running with Istio:

   ISTIO_INGRESS=$(kubectl get svc seldon-mesh -n seldon-mesh -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
   
   echo "Seldon Core 2: http://$ISTIO_INGRESS"
   

   Make a note of the IP address that is displayed in the output. This is the IP address that you require to test the installation.

Expose Seldon mesh service

It is important to expose seldon-service service to enable communication between deployed machine learning models and external clients or services. The Seldon Core 2 inference API is exposed through the seldon-mesh service in the seldon-mesh namespace. If you install Core 2 in multiple namespaces, you need to expose the seldon-mesh service in each of namespace.

1. Verify if the seldon-mesh service is running for example, in the namespace seldon.

   kubectl get svc -n seldon-mesh

   When the services are running you should see something similar to this:

   mlserver-0               ClusterIP      None             <none>          9000/TCP,9500/TCP,9005/TCP                                                                  43m
   seldon-mesh              LoadBalancer   34.118.225.130   34.90.213.15    80:32228/TCP,9003:31265/TCP                                                                 45m
   seldon-pipelinegateway   ClusterIP      None             <none>          9010/TCP,9011/TCP                                                                           45m
   seldon-scheduler         LoadBalancer   34.118.225.138   35.204.34.162   9002:32099/TCP,9004:32100/TCP,9044:30342/TCP,9005:30473/TCP,9055:32732/TCP,9008:32716/TCP   45m
   triton-0                 ClusterIP      None             <none>          9000/TCP,9500/TCP,9005/TCP 

2. Create a YAML file to create a VirtualService named iris-route in the namespace seldon-mesh. For example, create the seldon-mesh-vs.yaml file. Use your preferred text editor to create and save the file with the following content:

   apiVersion: networking.istio.io/v1alpha3
   kind: VirtualService
   metadata:
     name: iris-route
     namespace: seldon-mesh
   spec:
     gateways:
       - istio-system/seldon-gateway
     hosts:
       - "*"
     http:
       - name: iris-http
         match:
           - uri:
               prefix: /v2
         route:
           - destination:
               host: seldon-mesh.seldon-mesh.svc.cluster.local

3. Create a virtual service to expose the seldon-mesh service.

   kubectl apply -f seldon-mesh-vs.yaml

   When the virtual service is created, you should see this:

   virtualservice.networking.istio.io/iris-route created

Next Steps

Verify the installation

Additional Resources

• Istio Documentation

• GKE Ingress Guide

• AWS Documentation