Hello Minikube

This tutorial shows you how to run a sample app on Kubernetes using minikube. The tutorial provides a container image that uses NGINX to echo back all the requests.

Objectives

• Deploy a sample application to minikube.
• Run the app.
• View application logs.

Before you begin

This tutorial assumes that you have already set up minikube. See Step 1 in minikube start for installation instructions.

You also need to install kubectl. See Install tools for installation instructions.

Create a minikube cluster

minikube start

Open the Dashboard

Open the Kubernetes dashboard. You can do this two different ways:

• Launch a browser
• URL copy and paste

# Start a new terminal, and leave this running.
minikube dashboard

# Start a new terminal, and leave this running.
minikube dashboard --url

Create a Deployment

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.

1. Use the kubectl create command to create a Deployment that manages a Pod. The Pod runs a Container based on the provided Docker image.

   # Run a test container image that includes a webserver
   kubectl create deployment hello-node --image=registry.k8s.io/e2e-test-images/agnhost:2.39 -- /agnhost netexec --http-port=8080
   

2. 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
   

3. 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
   

4. View cluster events:

   kubectl get events
   

5. View the kubectl configuration:

   kubectl config view
   

6. View application logs for a container in a pod.

   kubectl logs hello-node-5f76cf6ccf-br9b5
   

   The output is similar to:

   I0911 09:19:26.677397       1 log.go:195] Started HTTP server on port 8080
   I0911 09:19:26.677586       1 log.go:195] Started UDP server on port  8081
   

Create a Service

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.

1. 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.

   The application code inside the test image only listens on TCP port 8080. If you used kubectl expose to expose a different port, clients could not connect to that other port.

2. View the Service you 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.

3. Run the following command:

   minikube service hello-node
   

   This opens up a browser window that serves your app and shows the app's response.

Enable addons

The minikube tool includes a set of built-in addons that can be enabled, disabled and opened in the local Kubernetes environment.

1. 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
   

2. Enable an addon, for example, metrics-server:

   minikube addons enable metrics-server
   

   The output is similar to:

   The 'metrics-server' addon is enabled
   

3. View the Pod and Service you created by installing that addon:

   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
   

4. Check the output from metrics-server:

   kubectl top pods
   

   The output is similar to:

   NAME                         CPU(cores)   MEMORY(bytes)   
   hello-node-ccf4b9788-4jn97   1m           6Mi             
   

   If you see the following message, wait, and try again:

   error: Metrics API not available
   

5. Disable metrics-server:

   minikube addons disable metrics-server
   

   The output is similar to:

   metrics-server was successfully disabled
   

Clean up

Now you can clean up the resources you created in your cluster:

kubectl delete service hello-node
kubectl delete deployment hello-node

Stop the Minikube cluster

minikube stop

Optionally, delete the Minikube VM:

# Optional
minikube delete

If you want to use minikube again to learn more about Kubernetes, you don't need to delete it.

Conclusion

This page covered the basic aspects to get a minikube cluster up and running. You are now ready to deploy applications.

What's next

• Tutorial to deploy your first app on Kubernetes with kubectl.
• Learn more about Deployment objects.
• Learn more about Deploying applications.
• Learn more about Service objects.