Hello K8s in Windows - Part 2

This is the second in a multi-part series that will show how to easily get Kubernetes up and running in Windows and deploy a sample application. Almost everything also applies to Linux, MacOS, etc.

The source code for this example can be found at https://github.com/cleverswine/hello-k8s-win

These posts are based on an intoductory presentation that I gave to my company.

Deploy to a local Kubernetes (k8s) cluster

Install the tools

Docker Desktop - enable Kubernetes after installing (https://hub.docker.com/editions/community/docker-ce-desktop-windows)
kubectl (https://kubernetes.io/docs/tasks/tools/install-kubectl/)

Verify connectivity to the k8s cluster

Once your local k8s cluster is up and running, you should be able to interact with it using kubectl.

PS> kubectl cluster-info
Kubernetes master is running at https://localhost:6445
KubeDNS is running at https://localhost:6445/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy

PS> kubectl get nodes
NAME                 STATUS    ROLES     AGE       VERSION
docker-for-desktop   Ready     master    2d        v1.10.3

Clone the sample repository

git clone https://github.com/cleverswine/hello-k8s-win

Build Docker images for the applications

Since the k8s cluster is running locally, we can just build the images locally and k8s will be able to find them. No need to publish to a remote repository.

PS> docker build -t calculator:1.0.0 ./src/Calculator/
...
Successfully built 6b8146f7fdeb
Successfully tagged calculator:1.0.0

PS> docker build -t webui:1.0.0 ./src/WebUI/
...
Successfully built 6b8146f7fdeb
Successfully tagged webui:1.0.0

Install rabbitmq and the applications

Use kubectl to do the installations

PS> kubectl apply -f deploy/rabbitmq.yaml
...
service/rabbitmq-headless created
service/rabbitmq created
statefulset.apps/rabbitmq created

PS> kubectl apply -f deploy/calculator.yaml
secret/calculator created
service/calculator created
deployment.apps/calculator created

PS> kubectl apply -f deploy/webui.yaml
secret/webui created
service/webui created
deployment.apps/webui created

Verify the installation

Use kubectl to explore what was deployed. Try things like: kubectl get all, kubectl get svc, etc.

PS> kubectl get pods
NAME                         READY     STATUS    RESTARTS   AGE
calculator-87dbdcdff-qh7f7   1/1       Running   0          16m
rabbitmq-0                   1/1       Running   0          16m
webui-675bfd674d-nthbz       1/1       Running   0          16m

Visit http://localhost:32500/ in the browser to see the WebUI in action.

Scale out the calculator

Manually scale the calculator service to two instances.

kubectl scale --replicas=2 deployment/calculator

Extras

Install the Kubernetes Dashboard (UI)

PS> kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v1.10.1/src/deploy/alternative/kubernetes-dashboard.yaml
...
deployment.apps "kubernetes-dashboard" created
service "kubernetes-dashboard" created

View the Kubernetes Dashboard

PS> kubectl proxy
Starting to serve on 127.0.0.1:8001

Visit http://localhost:8001/api/v1/namespaces/kube-system/services/kubernetes-dashboard/proxy in the browser.

Try some things

Scale out the service to increase parallel processing of messages

kubectl scale --replicas=3 deployment/calculator

Roll out an upgrade and note that there is 0 downtime

kubectl apply -f deploy/calculator.yaml

Kill the service (simulating a crash) and watch it recover

kubectl delete po --selector=app=webui

View application logs

kubectl logs --selector=app=webui
# stream the logs:
kubectl logs -f $(kubectl get po --selector=app=webui--output=jsonpath={.items..metadata.name})

Next: manage deployments with Helm (to be written)