Setting up Kubernetes with Minikube on an Elastic Metal server

• compute
• Kubernetes
• Minikube
• server
• Elastic-Metal-server

Kubernetes is an open-source platform for managing containerized workloads and services with a rapidly growing ecosystem. Kubernetes orchestrates computing, networking, and storage infrastructure on behalf of user workloads. The tool facilitates both: declarative configuration and automation and was released to the public by Google in 2014.

Kubernetes has several features. It can be thought of as:

• a container platform
• a microservices platform
• a portable cloud platform and a lot more.

Minikube runs a single-node Kubernetes cluster inside a VM on your computer or cloud server for developing and testing applications.

Minikube supports Kubernetes features such as:

• DNS
• NodePorts
• ConfigMaps and Secrets
• Dashboards
• Container Runtime: Docker, rkt, CRI-O and containerd
• Enabling CNI (Container Network Interface)
• Ingress

Downloading and Installing Minikube

1. Check if the CPU of your server supports hardware virtualization. The output of the following command shall not be empty:

   egrep --color 'vmx|svm' /proc/cpuinfo
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2. Minikube relies on a Hypervisor to run the Kubernetes VM. This tutorial uses KVM (Kernel Virtual Machine), but it is also possible to run Minikube on VirtualBox.

   apt-get install qemu qemu-kvm libvirt-bin virtinst curl
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3. Download the Minikube binary and make it executable:

   curl -Lo minikube https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64 && chmod +x minikube
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4. Copy the binary file to /usrlocal/bin/ to make it available system-wide, then remove the downloaded binary:

   cp minikube /usr/local/bin && rm minikube
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5. Download and install the KVM driver for Minikube:

   curl -LO https://storage.googleapis.com/minikube/releases/latest/docker-machine-driver-kvm2 && chmod +x docker-machine-driver-kvm2
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6. Copy the binary file to /usrlocal/bin/ to make it available system-wide, then remove the downloaded binary:

   cp docker-machine-driver-kvm2 /usr/local/bin/ && rm docker-machine-driver-kvm2
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7. Download and install kubectl, a CLI tool to manage Kubernetes:

   curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl && chmod +x kubectl
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8. Copy the binary file to /usrlocal/bin/ to make it available system-wide, then remove the downloaded binary:

   cp kubectl /usr/local/bin && rm kubectl
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Using Minikube

1. Start Minikube:

   minikube start --vm-driver=kvm2
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   An output informs you about the status of Minikube:

   ```
   😄  minikube v1.1.0 on linux (amd64)
   2019/05/27 15:11:47 No matching credentials were found, falling back on anonymous
   🔥  Creating kvm2 VM (CPUs=2, Memory=2048MB, Disk=20000MB) ...
   🐳  Configuring environment for Kubernetes v1.14.2 on Docker 18.09.6
   💾  Downloading kubeadm v1.14.2
   💾  Downloading kubelet v1.14.2
   🚜  Pulling images ...
   🚀  Launching Kubernetes ...
   ⌛  Verifying: apiserver proxy etcd scheduler controller dns
   🏄  Done! kubectl is now configured to use "minikube"
   ```
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2. Check the health status of minikube:

   minikube status
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   host: Running
   kubelet: Running
   apiserver: Running
   kubectl: Correctly Configured: pointing to minikube-vm at 192.168.39.101
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3. Start an Echoserver deployment:

   kubectl run hello-minikube --image=k8s.gcr.io/echoserver:1.14 --port=8080
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   Once the deployment is created, a message confirms the step:

   deployment.apps/hello-minikube created
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4. Check the running pods and configured deployments:

   kubectl get pods
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   NAME                              READY   STATUS    RESTARTS   AGE
   hello-minikube-56cdb79778-qj7sd   1/1     Running   0          3m47s
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   kubectl get deployments
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   NAME             READY   UP-TO-DATE   AVAILABLE   AGE
   hello-minikube   1/1     1            1           5m59s
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   Expose an echoserver deployment with NodePort

   kubectl expose deployment hello-minikube --type=NodePort
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5. curl the service created by running the following command:

   curl $(minikube service hello-minikube --url)
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   A response similar to this example is shown:

   Hostname: hello-minikube-56cdb79778-qj7sd
   
   Pod Information:
       -no pod information available-
   
   Server values:
       server_version=nginx: 1.13.3 - lua: 10008
   
   Request Information:
       client_address=172.17.0.1
       method=GET
       real path=/
       query=
       request_version=1.1
       request_scheme=http
       request_uri=http://192.168.39.101:8080/
   
   Request Headers:
       accept=*/*
       host=192.168.39.101:30090
       user-agent=curl/7.58.0
   
   Request Body:
       -no body in request-
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6. Delete the hello-minikube service:

   kubectl delete services hello-minikube
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7. Delete the deployment:

   kubectl delete deployment hello-minikube
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   A confirmation displays:

   deployment.extensions "hello-minikube" deleted
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8. Stop Minikube:

   minikube stop
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   A confirmation displays:

   ✋  Stopping "minikube" in kvm2 ...
   🛑  "minikube" stopped.
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For more information regarding Minikube and Kubernetes, check out the official documentation and the Minikube GitHub repository.