Kubernetes Workshop

Workshop Register:

2019-02-04 CNCJ Meetup: The Kubernetes Playground

Table of Contents

• Preparation
• Reference
• Lab 1: Getting to know the environment [5 minutes]
  • Accessing the Kubernetes cluster
  • 1.1 Accessing the cluster
  • 1.2 Accessing the dashboard
• Lab 2: Deploy your BookInfo application [10 minutes]
  • 2.1 Deploy using the manifest (without Helm)
  • 2.2 Check the status of the pods from the dashboard
  • 2.3 View the application logs
  • 2.4 Access your BookInfo application
  • 2.5 Update Details to version 2
  • 2.6 Deploying reviews-v2 and reviews-v3 alongside reviews-v1
• Lab 3: Cluster metrics with Prometheus [5 minutes]
  • 3.1 Cluster Metrics
    • Advanced
• Lab 4: Trace with Jaeger [5 minutes]
  • 4.1 Enable Istio
  • 4.2 Access Jaeger
• Lab 5: Deploy BookInfo using Helm [30 minutes]
  • 5.1 Clean up your BookInfo services
  • 5.2 Install tiller into your own namespace
  • 5.3 Install BookInfo using 4 helm charts
  • 5.4 Upgrade Reviews service to version 2
  • 5.5 Rollback Review service to version 1
  • 5.6 Install Reviews service version 3 alongside version 1
    • Advanced
• Lab 6: Assign a hostname to BookInfo [5 minutes]
  • 6.1 Installing Istio's VirtualService
    • Advanced
• Lab 7: Clean up [5 minutes]
  • 7.1 Delete the helm releases

Preparation

The Kubernetes cluster should be created prior to this workshop with the following addons:

• Kubernetes Dashboard
• Prometheus + Grafana (through prometheus-operator)
• Istio (with cert-manager enaabled) + Jaeger

You should have the following installed on your local machine:

• bash
  • Any shell/terminal that has bash, since there will be some bash scripts that need to be run.
• kubectl
  • Ensure that kubectl is in the $PATH of bash.
• helm

Reference

• username - The user that is created for you by the organiser of this workshop. This should be your first name appended with the first letter of your last name.
• your_namespace - The namespace that is created for you by the organiser for this workshop. This should be the same as your username.

Lab 1: Getting to know the environment [5 minutes]

Since everyone will be working in the same Kubernetes cluster, it is important that everyone works in their own namespace without interfering others.

Accessing the Kubernetes cluster

Your namespace should have been created for you by the organiser prior the workshop.

1.1 Accessing the cluster

The interaction with the cluster is done through kubectl. This is the Kubernetes client installed on your local machine that interacts with the Kubernetes cluster.

1. A bash script (enroll.sh) is provided in the repo root directory. Execute the provided script to enroll as a service account. Replace USERNAME=your_namespace (line 7) with the username that is given to you. E.g. USERNAME=harryl. Run the following in a bash terminal.

   chmod +x enroll.sh
   ./enroll.sh <token>

   • Your namespace/user name and <token> will be emailed to the email address that you entered in the Workshop Register.

2. Run kubectl get all --namespace your_namespace to verify that you can access the cluster. Don't worry, it's working if you see No resources found.

1.2 Accessing the dashboard

The Kubernetes dashboard is a powerful tool which provides a GUI for you to visualise the internal workings of the Kubernetes cluster.

1. Run kubectl config view.

2. Copy the token.

3. Run kubectl proxy, leave it running and do not close the terminal.

4. Open your web browser and navigate to: http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:https/proxy/.

5. Log in using the token method (paste the token that you retrieved from step 2).

6. Now you can view resources in your namespace.

Lab 2: Deploy your BookInfo application [10 minutes]

Disclaimer: The code for this lab is taken from Istio's BookInfo Application Tutorial.

We have a BookInfo application that is composed of 4 microservices. They have been "dockerised" and the docker images are stored on Docker Hub (public repository). Let's see how we can deploy these 4 services into our Kubernetes cluster.

2.1 Deploy using the manifest (without Helm)

1. Replace all namespace in the Deployment and Service resources in bookinfo.yml with your_namespace.

   # replace namespace: your_namespace with the namespace that is assigned to you.
   # e.g.
   namespace: harryl

2. Deploy the 4 services of BookInfo into your namespace

   kubectl apply -f bookinfo.yml

2.2 Check the status of the pods from the dashboard

We have just deployed our BookInfo application (as 4 separate services) into our cluster. Let's see how they are doing.

1. From the Kubernetes dashboard, navigate to your namespace.

2. Verify that the 4 services associated with the 6 pods are created correctly. They should be named, productpage-v1, details-v1, reviews-v1, reviews-v2, reviews-v3 and ratings-v1.

2.3 View the application logs

We can access the logs of the pods from the Kubernetes dashboard.

1. Select pods and view the logs of your pods (try and find where they are). Productpage does not log to stdout, so you won't be able to view any logs for this pod.

2.4 Access your BookInfo application

Now our services and pods are running fine. Let's access Productpage and see it in action.

1. Access the Productpage service (ensure that the proxy is still running)

   http://localhost:8001/api/v1/namespaces/your_namespace/services/productpage:9080/proxy/productpage

   • Replace your_namespace

2. Voila, You should be able to see your Productpage with a details section (Details service) and reviews section (Reviews service).

2.5 Update Details to version 2

So we realised that the information displayed in the details section is missing a Publisher field. We quickly made the changes to the Details service, build the docker image and pushed. Now let's see how we can swap out the old version.

1. Replace the container image with version 2 on line 47 of bookinfo.yml

   spec:
     containers:
     - name: details
       image: istio/examples-bookinfo-details-v2:1.8.0

2. Deploy the new version of Details

   kubectl apply -f bookinfo.yml

3. From the Kubernetes Dashboard, verify that the image for details-v1 pod is updated.

4. Access the Productpage service to see the new changes for the Details service. You should now see two new fields in the details section.

2.6 Deploying reviews-v2 and reviews-v3 alongside reviews-v1

You can route traffic between multiple pods by attaching them to a single service.

1. You will notice that under Reviews service in bookinfo.yml, there are two deployments (v2 and v3) that are commented out. Remove the comments and apply the manifest file again.

   # After you have uncommented the two reviews deployments
   kubectl apply -f bookinfo.yml

2. Refresh Productpage in your web browser. You will see that each time you refresh, the reviews section is different (no stars, black stars and red stars.)

Lab 3: Cluster metrics with Prometheus [5 minutes]

Now your application is deployed. Let's see how it's doing from the cluster's perspective.

3.1 Cluster Metrics

The Kubernetes cluster natively exposes metrics in the Prometheus format. We can view the metrics through Grafana.

1. Accessing Grafana through port forwarding.

   kubectl -n monitoring port-forward svc/grafana 3000

2. Login with username: user password: user.

3. Click Home on the top left. You should see a list of dashboards. You can now go and explore what each dashboard does.

Advanced

Prometheus can also be integrated with your application to expose any type of metrics you want. This requires you to instrument your code (this part does not come for free). The source code for the 4 microservices can be found at Bookinfo Sample. You can look at how you can instrument the code at Prometheus Client Libraries.

Lab 4: Trace with Jaeger [5 minutes]

Let's take a look at how a request to Productpage triggers a chain of events to the other 3 services. We can do this through tracing with Jaeger (integrated with Istio).

4.1 Enable Istio

1. Istio needs to be enabled for your namespace. Please ask any member of the workshop committee to enable Istio for your namespace.

2. After you have confirmation that Istio has been enabled for your namespace, head over to your Kubernetes Dashboard and delete all the pods (don't delete the deployments).

3. Your pods (the 4 Bookinfo services) will start up again. This time, you will see that every pod now has an istio-proxy sidecar container. This is the container that will monitor traffic to and from your pod.

4.2 Access Jaeger

1. Use port-forwarding to access Jaeger:

   kubectl -n istio-system port-forward svc/jaeger-query 16686

2. Now you can access the Jaeger UI from your web browser: http://localhost:16686

3. Note that you are viewing the requests coming in to the service mesh of the entire cluster, so you will see traffic to the other namespaces, not just yours.

Lab 5: Deploy BookInfo using Helm [30 minutes]

Let's install the BookInfo services using Helm charts. The helm charts for the services have already been created for you in the helm-charts directory.

5.1 Clean up your BookInfo services

1. Delete the deployments and services that we created before through a manifest.

   kubectl delete -f bookinfo.yml

2. Verify that all deployments and services are deleted by making use of the Kubernetes Dashboard.

5.2 Install tiller into your own namespace

For more info on this approach: Deploy Tiller in a namespace, restricted to deploying resources only in that namespace

1. Simply run:

   helm init --service-account tiller --tiller-namespace your_namespace

2. Ensure tiller is running:

   helm --tiller-namespace your_namespace list

5.3 Install BookInfo using 4 helm charts

1. Run the commands below from the helm-charts directory.

   helm --tiller-namespace your_namespace install \
   --namespace your_namespace \
   --name productpage \
   --set service.enabled=true \
   productpage --debug

2. Now do the same for the other 3 services.

   helm --tiller-namespace your_namespace install \
   --namespace your_namespace \
   --name reviews \
   --set service.enabled=true \
   reviews --debug

   helm --tiller-namespace your_namespace install \
   --namespace your_namespace \
   --name details \
   --set service.enabled=true \
   details --debug

   helm --tiller-namespace your_namespace install \
   --namespace your_namespace \
   --name ratings \
   --set service.enabled=true \
   ratings --debug

3. View the status of all 4 helm releases

   helm --tiller-namespace your_namespace list

4. Verify that your Productpage services is running from the Kubernetes Dashboard

5.4 Upgrade Reviews service to version 2

You will notice that we only have reviews-v1 deployed as a helm release. We have just added a new feature to display ratings as black stars as part of the Reviews service (reviews-v2). Let's upgrade our Reviews service to version 2.

1. We have already pushed a new image with the new feature, let's upgrade our release.

   helm --tiller-namespace your_namespace upgrade \
   --namespace your_namespace \
   --set service.enabled=true \
   --set image.repository=istio/examples-bookinfo-reviews-v2 \
   reviews reviews --debug

2. Check Productpage to see black stars under the Reviews section.

5.5 Rollback Review service to version 1

We realised that no one likes black stars for ratings! We have to revert back to version 1.

1. Have a look at the new revision for Reviews that you have created in 5.4

   helm --tiller-namespace your_namespace list

   • You should see two revisions for the reviews release.

2. Rollback to a previous version

   helm --tiller-namespace your_namespace rollback \
   reviews 1 --debug

5.6 Install Reviews service version 3 alongside version 1

Let's try using stars for ratings again. This time, we will use red stars instead of black stars. Let's deploy version 3 with version 1 so that we can do some A/B testing.

1. Install another helm release, but without enabling an extra service since we are using the same service as Reviews version 1.

   helm --tiller-namespace your_namespace install \
   --namespace your_namespace \
   --name reviews-v3 \
   --set image.repository=istio/examples-bookinfo-reviews-v3 \
   reviews --debug

2. Refresh Productpage a few times to see the Reviews section alternate between version 1 and version 3.

Advanced

Istio has advanced traffic management which includes Traffic Shifting. This is particularly useful if you want to do canary or A/B testing on your application. After you have completed Lab 6 you can experiment with this.

Lab 6: Assign a hostname to BookInfo [5 minutes]

We can access our BookInfo via kubectl proxy. But surely this is not how our users will access our application! Let's create an URL for our BookInfo.

6.1 Installing Istio's VirtualService

Istio has its own gateway and virtualservice custom resources that we can use to create a public facing endpoint. Configuring ingress using an Istio Gateway

A Gateway has been created for you in the default namespace. For the sake of simplicity and ease of management, you will deploy your own virtualservice to the default namespace as well.

The Gateway is integrated with cert-manager which provides a wild card certificate for our domain (*.library.yun.technology) via LetsEncrypt.

Let's install a Virtual Service for BookInfo.

1. Replace all occurrence of your_namespace in bookinfo-virtualservice.yml with your namespace.

2. Apply the manifest and wait about 3 minutes.

   kubectl apply -f bookinfo-virtualservice.yml

3. Access your Productpage service at https://your_namespace.library.yun.technology/productpage

Advanced

You can explore the different routing methods/strategies that virtualservice enables you to do with your application such as Traffic Shifting.

Lab 7: Clean up [5 minutes]

Delete all resources that you have created in your namespace.

7.1 Delete the helm releases

helm --tiller-namespace your_namespace delete productpage
helm --tiller-namespace your_namespace delete reviews
helm --tiller-namespace your_namespace delete reviews-v3
helm --tiller-namespace your_namespace delete details
helm --tiller-namespace your_namespace delete ratings