Deploy a sample application

Meshery, collaborative Kubernetes manager

To play with Istio and demonstrate some of it’s capabilities, you will deploy the example BookInfo application, which is included the Istio package.

This application is a polyglot composition of microservices are written in different languages and sample BookInfo application displays information about a book, similar to a single catalog entry of an online book store. Displayed on the page is a description of the book, book details (ISBN, number of pages, and so on), and a few book reviews.

It’s worth noting that these services have no dependencies on Istio, but make an interesting service mesh example, particularly because of the multitude of services, languages and versions for the reviews service.

As shown in the figure below, proxies are sidecarred to each of the application containers.

Figure: BookInfo deployed on the mesh

Sidecars proxy can be either manually or automatically injected into the pods. Automatic sidecar injection requires that your Kubernetes api-server supports admissionregistration.k8s.io/v1 or admissionregistration.k8s.io/v1beta1 or admissionregistration.k8s.io/v1beta2 APIs. Verify whether your Kubernetes deployment supports these APIs by executing:

kubectl api-versions | grep admissionregistration

If your environment does NOT supports either of these two APIs, then you may use manual sidecar injection to deploy the sample app.

As part of Istio deployment in Previous chapter, you have deployed the sidecar injector.

Deploying Sample App with Automatic sidecar injection

Istio, deployed as part of this workshop, will also deploy the sidecar injector. Let us now verify sidecar injector deployment.

kubectl -n istio-system get configmaps istio-sidecar-injector

Output:

NAME                     DATA   AGE
istio-sidecar-injector   2      9h

NamespaceSelector decides whether to run the webhook on an object based on whether the namespace for that object matches the selector.

kubectl get namespace -L istio-injection

Output:

NAME           STATUS    AGE       ISTIO-INJECTION
default        Active    1h        enabled
istio-system   Active    1h        disabled
kube-public    Active    1h
kube-system    Active    1h

Using Meshery, navigate to the Istio management page.

  1. Enter default in the Namespace field.
  2. Click the (+) icon on the Sample Application card and select BookInfo Application from the list.

This will do 3 things:

  1. Label default namespace for sidecar injection.
  2. Deploys all the BookInfo services in the default namespace.
  3. Deploys the virtual service and gateway needed to expose the BookInfo’s productpage application in the default namespace.
  1. Verify that the deployments are all in a state of AVAILABLE before continuing.
watch kubectl get deployment
  1. Choose a service, for instance productpage, and view it’s container configuration:
kubectl get po

kubectl describe pod productpage-v1-.....
  1. Examine details of the services:
kubectl describe svc productpage

Next, you will expose the BookInfo application to be accessed external from the cluster.

Follow this if the above steps did not work for you

Label the default namespace with istio-injection=enabled

kubectl label namespace default istio-injection=enabled

kubectl get namespace -L istio-injection

Output:

NAME           STATUS    AGE       ISTIO-INJECTION
default        Active    1h        enabled
istio-system   Active    1h        disabled
kube-public    Active    1h
kube-system    Active    1h

Applying this yaml file included in the Istio package you collected in Getting Started will deploy the BookInfo app in you cluster.

kubectl apply -f samples/bookinfo/platform/kube/bookinfo.yaml

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

Manual Sidecar Injection

Use this only when Automatic Sidecar injection doesn't work

To do a manual sidecar injection we will be using istioctl command:

curl https://raw.githubusercontent.com/istio/istio/master/samples/bookinfo/platform/kube/bookinfo.yaml | istioctl kube-inject -f - > newBookInfo.yaml

Observing the new yaml file reveals that additional container Istio Proxy has been added to the Pods with necessary configurations:

        image: docker.io/istio/proxyv2:1.3.0
        imagePullPolicy: IfNotPresent
        name: istio-proxy

We need to now deploy the new yaml using kubectl

kubectl apply -f newBookInfo.yaml

To do both in a single command:

kubectl apply -f <(curl https://raw.githubusercontent.com/istio/istio/master/samples/bookinfo/platform/kube/bookinfo.yaml | istioctl kube-inject -f -)

Now continue to Verify Bookinfo deployment.