Introduction

We will demonstrate how to perform a traffic split between two Kubernetes services. Specifically, we’ll divide the traffic sent to the root bookstore service between the bookstore-v1 and bookstore-v2 backends, also referred to as leaf services.

Requirements

• Azure subscription

• VS Code

• Azure CLI

Configure Traffic Split between Two Services

• First create a resource group inside your Azure portal by running az group create -l [region] -n [resource-group-name]

• Create Azure Kubernetes Service (AKS) cluster by running az aks create -g [resource-group-name] -n [cluster-name] -a open-service-mesh --generate-ssh-keys

The -a switch is used to add any add-ons, and in this case, to install Open Service Mesh.

• Set the default group to the resource group created by running

  az configure --defaults group=[resource-group-name]

• Merge your credentials with your local profile using

  az aks get-Credentials --name [aks-name]

• Check your current context to be sure it is set to your aks cluster kubectl config current-context

• Create three namespaces: bookstore, bookbuyer and bookwarehouse.

kubectl create ns bookbuyer

kubectl create ns bookstore

kubectl create ns bookwarehouse

• Confirm that the namespaces were created using kubectl get ns

• Add the namespaces to the open service mesh control plane by going to the Azure portal, opening your AKS cluster, and clicking Add

  

• Select the three namespaces and click Add

  

• Confirm that the namespaces has been added.

  

• Deploy three bookstore apps using the yaml file located here

kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.2/manifests/apps/bookbuyer.yaml

kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.2/manifests/apps/bookstore.yaml


kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.2/manifests/apps/bookwarehouse.yaml

• In order to see the changes in action, use one of the pods in any of the namespaces, I will be using bookbuyer. To do this, run kubectl get pod -n bookbuyer

• Copy the name of the pod and use kubectl port-forward [name-of-pod] -n bookbuyer 8081:14001 to map the app to your local machine on port 8081.

• Open your browser and search for localhost:8081 this piped via the terminal.

  

  As you can see, the version 1 of the app is seeing traffic which is simulated by the app.

NOTE: The OSM traffic policy is set to deny by default. We can see the services talking to each other and the bookbuyer service is able to access bookstore app.

• Turn enablePermissiveTrafficPolicyMode off using Azure portal. Navigate to your AKS in Azure portal and select Open Service Mesh and click Edit configuration

  

• Change it to false and click Review+create

  

• Tick confirm manifest changes and select Save

  

• As soon as you save the manifest changes, back on the portal, transaction stops.

  

• You can fix this by applying allow traffic policy which explicitly allow traffic across these services using kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.2/manifests/access/traffic-access-v1.yaml

• If you check your localhost browser, you will notice that the sales has resumed.

  

• Run the last command which is deploying the version 2 of the bookstore using kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.2/manifests/apps/bookstore-v2.yaml

• Traffic is now directed to version 2 of the bookstore app.

  

• Deploy the SMI TrafficSplit policy to route 100% of the traffic from the root bookstore service to the bookstore-v1 service backend. This ensures that all traffic is initially served by version v1 of the bookstore app, which corresponds to the pods behind bookstore-v1. Later, the TrafficSplit configuration will be updated to gradually route a portion of the traffic to version v2 via the bookstore-v2 service.

kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.2/manifests/split/traffic-split-v1.yaml

• The count for the books sold from the bookstore-v2 browser window should stop incrementing. This is because the current traffic split policy is weighted 100 for bookstore-v1 which exludes pods backing the bookstore-v2 service. You can verify the traffic split policy by running the following and viewing the Backends properties:

kubectl describe trafficsplit bookstore-split -n bookstore

• Update the SMI Traffic Split policy to direct 50 percent of the traffic sent to the root bookstore service to the bookstore service and 50 perfect to bookstore-v2 service by adding the bookstore-v2 backend to the spec and modifying the weight fields.

kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.2/manifests/split/traffic-split-50-50.yaml

• Update the bookstore-split TrafficSplit to configure all traffic to go to bookstore-v2:

kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.2/manifests/split/traffic-split-v2.yaml