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 webserverkubectl 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 

   (It may take some time for the pod to become available. If you see "0/1", try again in a few seconds.)

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 (replace pod name with the one you got from kubectl get pods).

   Note:

   Replace hello-node-5f76cf6ccf-br9b5 in the kubectl logs command with the name of the pod from the kubectl get pods command output.

   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:

# Optionalminikube 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.