What is MiniKube?

Whether you are a newbie to Kubernetes looking for a small setup to start or a developer who uses Kubernetes on a daily basis, Minikube is the tool that helps you quickly set up and run a Kubernetes environment locally. Minikube runs a single-node Kubernetes cluster inside a VM on your laptop for users looking to try out Kubernetes or develop with it day-to-day.

There are several options available for developers to install Minikube based on an operating system. You can read the detailed instructions for the three most popular operating systems in Minikube Setup.

However, if you are already an experienced Minikube user, skip the Minikube setup instructions and jump directly to the Setup OpenEBS section.

In this post, I will explain how to set up Kubernetes using Minikube directly on Ubuntu 16.04 (without using any VM drivers) and how to configure OpenEBS in hyper-converged mode or, more accurately, create your Container-Converged Infrastructure using OpenEBS Container Attached Storage (CAS).

Prerequisites

Minimum requirements for Minikube:

Hardware

• Machine Type – minimum 4 vCPUs.
• RAM – minimum 4 GB.
• VT-x/AMD-v virtualization must be enabled in your system BIOS

Software

• kubectl
• If using macOS:
  • xhyve driver, VirtualBox, or VMware Fusion.
• If using Linux:
  • VirtualBox or KVM.

NOTE: Minikube supports the --vm-driver=none option that runs Kubernetes components on the host and not in a VM. Docker is required to use this driver, but no the hypervisor.

• If using Windows:
  • VirtualBox or Hyper-V. VMware Workstation is not supported.

Since VirtualBox is available on all three platforms, I will describe this option.

Install VirtualBox

I will not cover the details of VirtualBox installation since it is very common and instructions are widely available online.

1. 1. Go to the Virtualbox website.
   2. Download and install the binaries required for your operating system.

Make sure that you install VirtualBox 5.2.0 Oracle VM VirtualBox Extension Pack as well.

When I was writing this blog post, the most current version was VirtualBox-5.2.0-118431.

Once VirtualBox is installed, you will see a screen similar to the following:

NOTE:  You can also use KVM, Hyper-V, and VMware Fusion.

Install Ubuntu

1. Create a new VM with 4 vCPUs, 4Gb memory, and 10GB disk space.
2. Download your preferred version of Ubuntu. I will be using Ubuntu 16.04.3 LTS.
3. Under VM Settings/Storage, mount your ISO image and power on the VM.
4. Install Ubuntu with default options. I used openebs/password as username/password for simplicity. If you use something else make sure to replace it with yours when you follow the instructions.
5. Finally login to your Ubuntu VM.
6. On your Ubuntu host, install the SSH server:
   sudo apt-get install openssh-server
7. Now you should be able to access your VM using SSH. Check the status by running:
   sudo service ssh status

   
   Example:
   

8. Disable firewall on your Ubuntu VM by running:
   sudo ufw disable
9. Install curl if it’s not already installed:
   sudo apt install curl
10. By default, for each virtual machine, VirtualBox creates a private network (10.0.2.x) which is connected to your laptop’s network using NAT. However, you may not be able to your VMs from your local host through SSH just yet. To access your VM, you need to configure port forwarding. In the network setting of the VM. Click on Advanced/Port Forwarding and create a rule with the Host port 3022 and Guest Port 22. Name it SSH and leave other fields blank.
11. Now you can connect to your Ubuntu VM from your laptop using SSH with localhost as the address and port 3022 instead of 22. Connect to your Ubuntu VM using the following credentials: openebs/password

Install Docker

To get the latest version of Docker, install it from the official Docker repository.

1. On your Ubuntu VM, run the following commands:
   curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
   sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
   sudo apt-get update

   

2. Confirm that you want to install the binaries from the Docker repository instead of the default Ubuntu repository by running:
   sudo apt-get install -y docker-ce

   

3. Install Docker and make sure it’s up and running after installation is complete:
   sudo apt-get install -y docker-ce
   sudo systemctl status docker

   

Add iSCSI Support

OpenEBS uses iSCSI to connect to the block volumes. Therefore, you need to install the open-iscsi package on your Ubuntu machine.

1. On your Ubuntu host, run:
   sudo apt-get update
   sudo apt-get install open-iscsi
   sudo service open-iscsi restart

   

2. Check that the iSCSI initiator name is configured:
   sudo cat /etc/iscsi/initiatorname.iscsi
3. Verify the iSCSI service is up and running:
   sudo service open-iscsi status

   Example:
   

Set up minikube and kubectl

1. On your Ubuntu host, install minikube by running:
   curl -Lo minikube https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
   chmod +x minikube
   sudo mv minikube /usr/local/bin/

   

2. Install kubectl:
   curl -Lo kubectl 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
   sudo mv kubectl /usr/local/bin/

   

3. Set up directories for storing minkube and kubectl configurations:
   mkdir $HOME/.kube || true touch $HOME/.kube/config
4. Set up an environment for minikube by adding the following lines to the end of the ~/.profile file:
   export MINIKUBE_WANTUPDATENOTIFICATION=false
   export MINIKUBE_WANTREPORTERRORPROMPT=false
   export MINIKUBE_HOME=$HOME
   export CHANGE_MINIKUBE_NONE_USER=true
   export KUBECONFIG=$HOME/.kube/config
5. Confirm that environment variables are saved in your profile file:
   cat ~/.profile

   Example:
   

6. Start minikube:
   sudo -E minikube start --vm-driver=none

   

7. If you forgot to install Docker, you will get the following error:
8. When using the none driver, the kubectl config and credentials generated will be root-owned and will appear in the root home directory. To fix this, set the correct permissions:
   sudo chown -R $USER $HOME/.kube
   sudo chgrp -R $USER $HOME/.kube
   sudo chown -R $USER $HOME/.minikube
   sudo chgrp -R $USER $HOME/.minikube

Verify minikube configuration

Verify that minikube is configured correctly and it has started by running:

Example:

Note

• If the minikube status displays Stopped, add the sudo minikube start command.
• If you forgot to set the permissions, minikube will display errors indicating permissions denied to configuration files, fix the permissions by running the following commands:
  sudo chown -R $USER $HOME/.kube
  sudo chgrp -R $USER $HOME/.kube
  sudo chown -R $USER $HOME/.minikube
  sudo chgrp -R $USER $HOME/.minikube

Verify Kubernetes configuration

Check that kubectl is configured and services are up and running by getting the list of Kubernetes nodes and pods:

Example:

Set up OpenEBS

1. Download the latest OpenEBS Operator files using the following commands:
   git clone https://github.com/openebs/openebs.git
   cd openebs/k8s

   Example:
   

2. By default, OpenEBS launches OpenEBS Volumes with two replicas. To set one replica, as is the case with a single-node Kubernetes cluster, in the openebs-operator.yaml file, specify the environment variable DEFAULT_REPLICA_COUNT=1. This is supported in OpenEBS version 0.4 onwards.
3. Apply the configuration changes:
   kubectl apply -f openebs-operator.yaml

   

4. Add the OpenEBS storage classes that can then be used by developers and applications:
   kubectl apply -f openebs-storageclasses.yaml

   

Running stateful applications with OpenEBS storage

To use OpenEBS as persistent storage for your stateful workloads, set the storage class in the Persistent Volume Claim (PVC) of your application to one of the OpenEBS storage class.

1. 1. Get the list of storage classes using the following command. Choose the storage class that best suits your application.
      kubectl get sc

      

You can find samples of YAML files for stateful workloads using OpenEBS under the the openebs/k8s/demo folder.

Now you have your Kubernetes cluster up and running. In my next blog posts, I will cover installation of stateful workloads such as Cassandra and PostgreSQL, as well as benefits of running your stateful workloads on OpenEBS. Stay tuned!

Also published on Medium.