This tutorial shows you how to run a simple Hello World Node.js app on Kubernetes using Minikube and Katacoda. Katacoda provides a free, in-browser Kubernetes environment.
Note: You can also follow this tutorial if you’ve installed Minikube locally.
This tutorial provides a container image built from the following files:
minikube/server.js
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minikube/Dockerfile
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For more information on the docker build
command, read the Docker documentation.
Click Launch Terminal
Note: If you installed Minikube locally, runminikube start
.
Open the Kubernetes dashboard in a browser:
minikube dashboard
Katacoda environment only: At the top of the terminal pane, click the plus sign, and then click Select port to view on Host 1.
Katacoda environment only: Type 30000
, and then click Display Port.
A Kubernetes Pod is a group of one or more Containers, tied together for the purposes of administration and networking. The Pod in this tutorial has only one Container. A Kubernetes Deployment checks on the health of your Pod and restarts the Pod’s Container if it terminates. Deployments are the recommended way to manage the creation and scaling of Pods.
Use the kubectl create
command to create a Deployment that manages a Pod. The
Pod runs a Container based on the provided Docker image.
kubectl create deployment hello-node --image=gcr.io/hello-minikube-zero-install/hello-node
View the Deployment:
kubectl get deployments
The output is similar to:
NAME READY UP-TO-DATE AVAILABLE AGE
hello-node 1/1 1 1 1m
View the Pod:
kubectl get pods
The output is similar to:
NAME READY STATUS RESTARTS AGE
hello-node-5f76cf6ccf-br9b5 1/1 Running 0 1m
View cluster events:
kubectl get events
View the kubectl
configuration:
kubectl config view
Note: For more information aboutkubectl
commands, see the kubectl overview.
By default, the Pod is only accessible by its internal IP address within the
Kubernetes cluster. To make the hello-node
Container accessible from outside the
Kubernetes virtual network, you have to expose the Pod as a
Kubernetes Service.
Expose the Pod to the public internet using the kubectl expose
command:
kubectl expose deployment hello-node --type=LoadBalancer --port=8080
The --type=LoadBalancer
flag indicates that you want to expose your Service
outside of the cluster.
View the Service you just created:
kubectl get services
The output is similar to:
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
hello-node LoadBalancer 10.108.144.78 <pending> 8080:30369/TCP 21s
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 23m
On cloud providers that support load balancers,
an external IP address would be provisioned to access the Service. On Minikube,
the LoadBalancer
type makes the Service accessible through the minikube service
command.
Run the following command:
minikube service hello-node
Katacoda environment only: Click the plus sign, and then click Select port to view on Host 1.
Katacoda environment only: Note the 5 digit port number displayed opposite to 8080
in services output. This port number is randomly generated and it can be different for you. Type your number in the port number text box, then click Display Port. Using the example from earlier, you would type 30369
.
This opens up a browser window that serves your app and shows the “Hello World” message.
Minikube has a set of built-in addonsResources that extend the functionality of Kubernetes. that can be enabled, disabled and opened in the local Kubernetes environment.
List the currently supported addons:
minikube addons list
The output is similar to:
addon-manager: enabled
dashboard: enabled
default-storageclass: enabled
efk: disabled
freshpod: disabled
gvisor: disabled
helm-tiller: disabled
ingress: disabled
ingress-dns: disabled
logviewer: disabled
metrics-server: disabled
nvidia-driver-installer: disabled
nvidia-gpu-device-plugin: disabled
registry: disabled
registry-creds: disabled
storage-provisioner: enabled
storage-provisioner-gluster: disabled
Enable an addon, for example, metrics-server
:
minikube addons enable metrics-server
The output is similar to:
metrics-server was successfully enabled
View the Pod and Service you just created:
kubectl get pod,svc -n kube-system
The output is similar to:
NAME READY STATUS RESTARTS AGE
pod/coredns-5644d7b6d9-mh9ll 1/1 Running 0 34m
pod/coredns-5644d7b6d9-pqd2t 1/1 Running 0 34m
pod/metrics-server-67fb648c5 1/1 Running 0 26s
pod/etcd-minikube 1/1 Running 0 34m
pod/influxdb-grafana-b29w8 2/2 Running 0 26s
pod/kube-addon-manager-minikube 1/1 Running 0 34m
pod/kube-apiserver-minikube 1/1 Running 0 34m
pod/kube-controller-manager-minikube 1/1 Running 0 34m
pod/kube-proxy-rnlps 1/1 Running 0 34m
pod/kube-scheduler-minikube 1/1 Running 0 34m
pod/storage-provisioner 1/1 Running 0 34m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/metrics-server ClusterIP 10.96.241.45 <none> 80/TCP 26s
service/kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP 34m
service/monitoring-grafana NodePort 10.99.24.54 <none> 80:30002/TCP 26s
service/monitoring-influxdb ClusterIP 10.111.169.94 <none> 8083/TCP,8086/TCP 26s
Disable metrics-server
:
minikube addons disable metrics-server
The output is similar to:
metrics-server was successfully disabled
Now you can clean up the resources you created in your cluster:
kubectl delete service hello-node
kubectl delete deployment hello-node
Optionally, stop the Minikube virtual machine (VM):
minikube stop
Optionally, delete the Minikube VM:
minikube delete
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