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Distributing Bookinfo services across clusters with Skupper

This tutorial demonstrates how to distribute Istio Bookinfo Application microservices across multiple public and private clusters. The services require no coding changes to work in the distributed application environment. With Skupper the application behaves as if all the services are running in the same cluster.

This example further illustrates how services in a public cluster may access services in a private cluster when the private cluster will not accept incoming network connections and the private cluster has no ingress routes. Skupper infrastructure securely provides this connectivity and it does so without special user permissions, firewall rules, VPNs, sidecars, or system administrator actions.

In this tutorial you will deploy the productpage and ratings services on a remote, public cluster in namespace aws-eu-west and the details and reviews services in a local, on-premises cluster in namespace laptop.

Watch a video demonstrating this tutorial:

Overview
Prerequisites
Step 1: Deploy the Bookinfo application
Step 2: Expose the public productpage service
Step 3: Observe that the application does not work
Step 4: Set up Skupper
Step 5: Connect your Skupper installations
Step 6: Virtualize the services you want shared
Step 7: Observe that the application works
Clean up
Next steps
Credits

Overview

Figure 1 - Bookinfo service deployment

Figure 1 shows how the services will be deployed.

Each cluster runs two of the application services.
An ingress route to the productpage service provides internet user access to the application.

If all the services were installed on the public cluster then the application would work as originally designed. However, since two of the services are on the laptop cluster the application fails. productpage can not send requests to details or to reviews.

This demo will show how Skupper can solve the connectivity problem presented by this arrangement of service deployments.

Figure 2 - Bookinfo service deployment with Skupper

Figure 2 shows how the clusters appear after Skupper has been set up.

Skupper is a distributed system with installations running in one or more clusters or namespaces. Connected Skupper installations share information about what services each installation exposes. Each Skupper installation learns which services are exposed on every other installation. Skupper then runs proxy service endpoints in each namespace to properly route requests to or from every exposed service.

In the public namespace the details and reviews proxies intercept requests for their services and forward them to the Skupper network.
In the private namespace the details and reviews proxies receive requests from the Skupper network and send them to the related service.
In the private namespace the ratings proxy intercepts requests for its service and forwards them to the Skupper network.
In the public namespace the ratings proxy receives requests from the Skupper network and sends them to the related service.

Prerequisites

To run this tutorial you will need:

The kubectl command-line tool, version 1.15 or later (installation guide)
The skupper command-line tool, the latest version (installation guide)
The oc command-line tool, if using OKD for your public cluster (installation guide)
Two Kubernetes namespaces, from any providers you choose, on any clusters you choose
The yaml files from https://github.com/skupperproject/skupper-example-bookinfo.git
Two logged-in console terminals, one for each cluster or namespace
If you are using minikube as your public cluster, run $ minikube tunnel in a separate terminal

Step 1: Deploy the Bookinfo application

This step creates a service and a deployment for each of the four Bookinfo microservices.

Namespace aws-eu-west:

$ kubectl apply -f public-cloud.yaml
service/productpage created
deployment.extensions/productpage-v1 created
service/ratings created
deployment.extensions/ratings-v1 created

Namespace laptop:

$ kubectl apply -f private-cloud.yaml 
service/details created
deployment.extensions/details-v1 created
service/reviews created
deployment.extensions/reviews-v3 created

Step 2: Expose the public productpage service

Namespace aws-eu-west:

$ kubectl expose deployment/productpage-v1 --port 9080 --type LoadBalancer

The Bookinfo application is accessed from the public internet through this ingress port to the productpage service.

If you are running your public cluster namespace aws-eu-west on OKD, then you might need to create a route:

$ oc create route edge productpage --service=productpage

Step 3: Observe that the application does not work

The web address for the Bookinfo application can be discovered from namespace aws-eu-west:

$ echo $(kubectl get service/productpage -o jsonpath='http://{.status.loadBalancer.ingress[0].hostname}:9080')

If you are running a minikube cluster, then use:

$ echo $(kubectl get service/productpage -o jsonpath='http://{.status.loadBalancer.ingress[0].ip}:9080')

If you are running an OKD cluster, then use:

$ echo $(oc get route/productpage -o jsonpath='https://{.status.ingress[0].host}')

Open the address in a web browser. Productpage responds but the page will show errors because the services in namespace laptop are not reachable.

Let's fix that now.

Step 4: Set up Skupper

This step initializes the Skupper environment on each cluster.

Namespace laptop:

$ skupper init

Namespace aws-eu-west:

$ skupper init

Now the Skupper infrastructure is running. Use skupper status in each console terminal to see that Skupper is available.

$ skupper status
Skupper is enabled for namespace '"<ns>" in interior mode'. It is not connected to any other sites. It has no exposed services.

As you move through the steps that follow, you can use skupper status at any time to check your progress.

Step 5: Connect your Skupper installations

Now you need to connect your namespaces with a Skupper connection. This is a two step process.

The skupper token create <file> command directs Skupper to generate a secret token file with certificates that grant permission to other Skupper instances to connect to this Skupper's network.

Note: Protect this file as you would any file that holds login credentials.
The skupper link create <file> command directs Skupper to connect to another Skupper's network. This step completes the Skupper connection.

Note that in this arrangement the Skupper instances join to form peer networks. Typically the Skupper opening the network port will be on the public cluster. A cluster running on laptop may not even have an address that is reachable from the internet. After the connection is made the Skupper network members are peers and it does not matter which Skupper opened the network port and which connected to it.

The console terminals in this demo are run by the same user on the same host. This makes the token file in the ${HOME} directory available to both terminals. If your terminals are on different machines then you may need to use scp or a similar tool to transfer the token file to the system hosting the laptop terminal.

Generate a Skupper network connection token

Namespace aws-eu-west:

$ skupper token create ${HOME}/PVT-to-PUB-connection-token.yaml

Open a Skupper connection

Namespace laptop:

$ skupper link create ${HOME}/PVT-to-PUB-connection-token.yaml

Check the connection

Namespace aws-eu-west:

$ skupper status
Skupper is enabled for namespace '"aws-eu-west" in interior mode'. It is connected to 1 other site. It has no exposed service.

Namespace laptop:

$ skupper status
Skupper is enabled for namespace '"laptop" in interior mode'. It is connected to 1 other site. It has no exposed service.

Step 6: Virtualize the services you want shared

You now have a Skupper network capable of multi-cluster communication but no services are associated with it. This step uses the kubectl annotate command to notify Skupper that a service is to be included in the Skupper network.

Skupper uses the annotation as the indication that a service must be virtualized. The service that receives the annotation is the physical target for network requests and the proxies that Skupper deploys in the other namespaces are the virtual targets for network requests. The Skupper infrastructure then routes requests between the virtual services and the target service.

Namespace aws-eu-west:

$ kubectl annotate service ratings skupper.io/proxy=http
service/ratings annotated

Namespace laptop:

$ kubectl annotate service details skupper.io/proxy=http
service/details annotated

$ kubectl annotate service reviews skupper.io/proxy=http
service/reviews annotated

Alternatively, Skupper command expose can be used as well:

Namespace aws-eu-west:

$ skupper expose service ratings --address ratings --protocol http
service ratings exposed as ratings

Namespace laptop:

$ skupper expose service details --address details --protocol http
service details exposed as details

$ skupper expose service reviews --address reviews --protocol http
service reviews exposed as reviews

Skupper is now making the annotated services available to every namespace in the Skupper network. The Bookinfo application will work because the productpage service on the public cluster has access to the details and reviews services on the private cluster and because the reviews service on the private cluster has access to the ratings service on the public cluster.

Step 7: Observe that the application works

The web address for the Bookinfo app can be discovered from namespace aws-eu-west:

$ echo $(kubectl get service/productpage -o jsonpath='http://{.status.loadBalancer.ingress[0].hostname}:9080')

If you are running a minikube cluster, then use:

$ echo $(kubectl get service/productpage -o jsonpath='http://{.status.loadBalancer.ingress[0].ip}:9080')

If you are running an OKD cluster, then use:

$ echo $(oc get route/productpage -o jsonpath='https://{.status.ingress[0].host}')

Open the address in a web browser. The application now works with no errors.

Clean up

Skupper and the Bookinfo services may be removed from the clusters.

Namespace aws-eu-west:

skupper delete
kubectl delete -f public-cloud.yaml

Namespace laptop:

skupper delete
kubectl delete -f private-cloud.yaml

Next steps

Credits

This demo uses public Bookinfo images provided by docker.io/maistra.

Awesome

Distributing Bookinfo services across clusters with Skupper

Table of contents

Overview

Figure 1 - Bookinfo service deployment

Figure 2 - Bookinfo service deployment with Skupper

Prerequisites

Step 1: Deploy the Bookinfo application

Step 2: Expose the public productpage service

Step 3: Observe that the application does not work

Step 4: Set up Skupper

Step 5: Connect your Skupper installations

Generate a Skupper network connection token

Open a Skupper connection

Check the connection

Step 6: Virtualize the services you want shared

Step 7: Observe that the application works

Clean up

Next steps

Credits