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Lab 3 - Exposing services through Istio Ingress Gateway

The components deployed on the service mesh by default are not exposed outside the cluster. An Ingress Gateway is deployed as a Kubernetes service of type LoadBalancer (or NodePort). To make Bookinfo accessible external to the cluster, you have to create an Istio Gateway for the Bookinfo application and also define an Istio VirtualService with the routes we need.

3.1 Inspecting the Istio Ingress Gateway

The ingress gateway gets exposed as a normal Kubernetes service of type LoadBalancer (or NodePort):

kubectl get svc istio-ingressgateway -n istio-system -o yaml

Because the Istio Ingress Gateway is an Envoy Proxy you can inspect it using the admin routes. First find the name of the istio-ingressgateway:

kubectl get pods -n istio-system

Copy and paste your ingress gateway's pod name. Execute:

kubectl -n istio-system exec -it <istio-ingressgateway-...> bash

You can view the statistics, listeners, routes, clusters and server info for the Envoy proxy by forwarding the local port:

curl localhost:15000/help
curl localhost:15000/stats
curl localhost:15000/listeners
curl localhost:15000/clusters
curl localhost:15000/server_info

See the admin docs for more details.

Also it can be helpful to look at the log files of the Istio ingress controller to see what request is being routed.

Before we check the logs, let us get out of the container back on the host:

exit

Now let us find the ingress pod and output the log:

kubectl logs istio-ingressgateway-... -n istio-system

3.2 View Istio Ingress Gateway for Bookinfo

3.2.1 - View the Gateway and VirtualServices

Check the created Istio Gateway and Istio VirtualService to see the changes deployed:

kubectl get gateway
kubectl get gateway -o yaml

kubectl get virtualservices
kubectl get virtualservices -o yaml

3.2.2 - Find the external port of the Istio Ingress Gateway by running:

kubectl get service istio-ingressgateway -n istio-system -o wide

To just get the first port of istio-ingressgateway service, we can run this:

kubectl get service istio-ingressgateway -n istio-system --template='{{(index .spec.ports 1).nodePort}}'

3.2.3 - Create a DNS entry:

Modify you local /etc/hosts file to add an entry for your sample application.

127.0.0.1. bookinfo.meshery.io

The HTTP port is usually 31380.

Or run these commands to retrieve the full URL:

echo "http://$(kubectl get nodes --selector=kubernetes.io/role!=master -o jsonpath={.items[0].status.addresses[?\(@.type==\"InternalIP\"\)].address}):$(kubectl get svc istio-ingressgateway -n istio-system -o jsonpath='{.spec.ports[1].nodePort}')/productpage"

The HTTP port is usually 31380.

Or run these commands to retrieve the full URL:

echo "http://$(kubectl get nodes --selector=kubernetes.io/role!=master -o jsonpath={.items[0].status.addresses[?\(@.type==\"InternalIP\"\)].address}):$(kubectl get svc istio-ingressgateway -n istio-system -o jsonpath='{.spec.ports[1].nodePort}')/productpage"

3.3 Apply default destination rules

Before we start playing with Istio's traffic management capabilities we need to define the available versions of the deployed services. They are called subsets, in destination rules.

Using Meshery, navigate to the Custom yaml page, and apply the below to create the subsets for BookInfo:

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: productpage
spec:
  host: productpage
  subsets:
    - name: v1
      labels:
        version: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
    - name: v1
      labels:
        version: v1
    - name: v2
      labels:
        version: v2
    - name: v3
      labels:
        version: v3
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: ratings
spec:
  host: ratings
  subsets:
    - name: v1
      labels:
        version: v1
    - name: v2
      labels:
        version: v2
    - name: v2-mysql
      labels:
        version: v2-mysql
    - name: v2-mysql-vm
      labels:
        version: v2-mysql-vm
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: details
spec:
  host: details
  subsets:
    - name: v1
      labels:
        version: v1
    - name: v2
      labels:
        version: v2

This creates destination rules for each of the BookInfo services and defines version subsets

Manual step for can be found here

In a few seconds we should be able to verify the destination rules created by using the command below:

kubectl get destinationrules


kubectl get destinationrules -o yaml

3.4 - Browse to BookInfo

Browse to the website of the Bookinfo. To view the product page, you will have to have a DNS configured for bookinfo.meshery.io to localhost. Now visit bookinfo.meshery.io/productpage to view the page.

3.4.1 - Reload Page

Now, reload the page multiple times and notice how it round robins between v1, v2 and v3 of the reviews service.

3.4.2 - More Details

The Detailed description of how it works can be found here.

3.5 Inspect the Istio proxy of the productpage pod

To better understand the istio proxy, let's inspect the details. Let us exec into the productpage pod to find the proxy details. To do so we need to first find the full pod name and then exec into the istio-proxy container:

kubectl get pods
kubectl exec -it productpage-v1-... -c istio-proxy  sh

Once in the container look at some of the envoy proxy details by inspecting it's config file:

ps aux
ls -l /etc/istio/proxy
cat /etc/istio/proxy/envoy-rev0.json

For more details on envoy proxy please check out their admin docs.

As a last step, lets exit the container:

exit

Appendix

Default destination rules

Run the following command to create default destination rules for the Bookinfo services:

kubectl apply -f samples/bookinfo/networking/destination-rule-all-mtls.yaml

Continue to Lab 4: Observability


Alternative, manual installation steps are provided for reference below. No need to execute these if you have performed the steps above.

Run the following command to create default destination rules for the Bookinfo services:

kubectl apply -f samples/bookinfo/networking/destination-rule-all-mtls.yaml

3.2.1 - Configure the Bookinfo route with the Istio Ingress gateway:

We can create a virtualservice & gateway for bookinfo app in the ingress gateway by running the following:

kubectl apply -f samples/bookinfo/networking/bookinfo-gateway.yaml

3.2.2 - View the Gateway and VirtualServices