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.
Note:
Only execute the instructions in Step 1, Installation. The rest is covered on this page.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:
Open a new terminal, and run:
# Start a new terminal, and leave this running.
minikube dashboard
Now, switch back to the terminal where you ran minikube start
.
Note:
The dashboard
command enables the dashboard add-on and opens the proxy in the default web browser.
You can create Kubernetes resources on the dashboard such as Deployment and Service.
To find out how to avoid directly invoking the browser from the terminal and get a URL for the web dashboard, see the "URL copy and paste" tab.
By default, the dashboard is only accessible from within the internal Kubernetes virtual network.
The dashboard
command creates a temporary proxy to make the dashboard accessible from outside the Kubernetes virtual network.
To stop the proxy, run Ctrl+C
to exit the process.
After the command exits, the dashboard remains running in the Kubernetes cluster.
You can run the dashboard
command again to create another proxy to access the dashboard.
If you don't want minikube to open a web browser for you, run the dashboard
subcommand with the
--url
flag. minikube
outputs a URL that you can open in the browser you prefer.
Open a new terminal, and run:
# Start a new terminal, and leave this running.
minikube dashboard --url
Now, you can use this URL and switch back to the terminal where you ran minikube start
.
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.
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
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.)
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
View application logs for a container in a pod (replace pod name with the one you got from
kubectl get pods
).Note:
Replacehello-node-5f76cf6ccf-br9b5
in thekubectl logs
command with the name of the pod from thekubectl 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.
Warning:
The agnhost container has a/shell
endpoint, which is useful for
debugging, but dangerous to expose to the public internet. Do not run this on an
internet-facing cluster, or a production cluster.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.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 theminikube service
command.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.
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:
The 'metrics-server' addon is enabled
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
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
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.