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Lab1 - Creating Distributed Services

In this step, we'll install a sample application into the system. This application is included in Istio itself for demonstrating various aspects of it, but the application isn't tied exclusively to Istio - it's an ordinary microservice application that could be installed to any OpenShift instance with or without Istio.

The sample application is called Bookinfo, a simple application that 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.

The BookInfo application is broken into four separate microservices:

  • productpage - The productpage microservice calls the details and reviews microservices to populate the page.
  • details - The details microservice contains book information.
  • reviews - The reviews microservice contains book reviews. It also calls the ratings microservice to show a "star" rating for each book.
  • ratings - The ratings microservice contains book rating information that accompanies a book review.

There are 3 versions of the reviews microservice:

  • Version v1 does not call the ratings service.
  • Version v2 calls the ratings service, and displays each rating as 1 to 5 black stars.
  • Version v3 calls the ratings service, and displays each rating as 1 to 5 red stars.

The end-to-end architecture of the application is shown below.

![Bookinfo Architecture]({% image_path istio_bookinfo.png %})

####1. Deploy Bookinfo Application

First, open a new browser with the [OpenShift web console]({{ CONSOLE_URL}}){:target="_blank"}

![openshift_login]({% image_path openshift_login.png %})

Login using:

  • Username: userXX
  • Password: r3dh4t1!

NOTE: Use of self-signed certificates

When you access the [OpenShift web console]({{ CONSOLE_URL}}) or other URLs via HTTPS protocol, you will see browser warnings like Your Connection is not secure since this workshop uses self-signed certificates (which you should not do in production!). For example, if you're using Chrome, to accept the warning, Click on Advanced then Proceed to... to access the page.

![warning]({% image_path browser_warning.png %})

Other browsers have similar procedures to accept the security exception.

Once logged in, uou will see the OpenShift landing page:

![openshift_landing]({% image_path openshift_landing.png %})

The project displayed in the landing page depends on which labs you will run today. If you will develop Service Mesh and Identity then you will see pre-created projects as the above screeenshot.

Although your Eclipse Che workspace is running on the Kubernetes cluster, it's running with a default restricted Service Account that prevents you from creating most resource types. If you've completed other modules, you're probably already logged in, but let's login again: open a Terminal and issue the following command:

oc login https://$KUBERNETES_SERVICE_HOST:$KUBERNETES_SERVICE_PORT --insecure-skip-tls-verify=true

Enter your username and password assigned to you:

  • Username: userXX
  • Password: r3dh4t1!

You should see like:

Login successful.

You have access to the following projects and can switch between them with 'oc project <projectname>':

  * default
    istio-system
    userXX-bookinfo
    userXX-catalog
    userXX-cloudnative-pipeline
    userXX-cloudnativeapps
    userXX-inventory

Using project "default".
Welcome! See 'oc help' to get started.

Change to the empty userXX-bookinfo project via CodeReady Workspaces Terminal and this command (you should replace userXX with your username):

oc project userXX-bookinfo

Deploy the Bookinfo application in the bookinfo project:

oc apply -f /projects/cloud-native-workshop-v2m3-labs/istio/bookinfo.yaml

Next, open the istio/bookinfo-gateway.yaml file in CodeReady.

Look for the REPLACE WITH YOUR BOOKINFO APP URL (there are 2 of them) and replace them with your custom url:

userXX-bookinfo-istio-system.{{ROUTE_SUBDOMAIN}}

Be sure to substitute your username for userXX!

![gateway]({% image_path bookinfo-gateway.png %})

And then create the ingress gateway for Bookinfo:

oc apply -f /projects/cloud-native-workshop-v2m3-labs/istio/bookinfo-gateway.yaml

For your conveience, set an environment variable in the CodeReady Workspaces Terminal:

echo "export BOOK_URL=REPLACE WITH YOUR BOOKINFO APP URL" >> ~/.bashrc && source ~/.bashrc (again, replace the same value as above).

When the app is installed, each Pod will get an additional sidecar container as described earlier.

Let's wait for our application to finish deploying. Go to the overview page in userxx-bookinfo project:

![bookinfo]({% image_path bookinfo-deployed.png %})

Or you can execute the following commands to wait for the deployment to complete and result successfully rolled out:

oc rollout status -w deployment/productpage-v1 && \
 oc rollout status -w deployment/reviews-v1 && \
 oc rollout status -w deployment/reviews-v2 && \
 oc rollout status -w deployment/reviews-v3 && \
 oc rollout status -w deployment/details-v1 && \
 oc rollout status -w deployment/ratings-v1

Confirm that Bookinfo has been successfully deployed via your own Gateway URL:

curl -o /dev/null -s -w "%{http_code}\n" http://$BOOK_URL/productpage

You should get 200 as a response.

Add default destination rules (we'll alter this later to affect routing of requests):

oc apply -f /projects/cloud-native-workshop-v2m3-labs/istio/destination-rule-all.yaml

List all available destination rules:

oc get destinationrules -o yaml

####2. Access Bookinfo

Open the application in your web browser to make sure if it's working. You will find the URL via running the following command in CodeReady Workspaces Terminal:

echo http://$BOOK_URL/productpage

It should look something like:

![Bookinfo App]({% image_path bookinfo.png %})

Reload the page multiple times. The three different versions of the Reviews service show the star ratings differently - v1 shows no stars at all, v2 shows black stars, and v3 shows red stars:

  • v1: ![no stars]({% image_path stars-none.png %})
  • v2: ![black stars]({% image_path stars-black.png %})
  • v3: ![red stars]({% image_path stars-red.png %})

That's because there are 3 versions of reviews deployment for our reviews service. Istio’s load-balancer is using a round-robin algorithm to iterate through the 3 instances of this service.

You should now have your OpenShift Pods running and have an Envoy sidecar in each of them alongside the microservice. The microservices are productpage, details, ratings, and reviews. Note that you'll have three versions of the reviews microservice:

oc get pods --selector app=reviews

NAME                          READY   STATUS    RESTARTS   AGE
reviews-v1-7754bbd88-dm4s5    2/2     Running   0          12m
reviews-v2-69fd995884-qpddl   2/2     Running   0          12m
reviews-v3-5f9d5bbd8-sz29k    2/2     Running   0          12m

Notice that each of the microservices shows 2/2 containers ready for each service (one for the service and one for its sidecar).

Now that we have our application deployed and linked into the Istio service mesh, let's take a look at the immediate value we can get out of it without touching the application code itself!

#####Congratulations!