Introduction

This project provides tools for preparing kubernetes certifications such as CKA, CKS and CKAD. The unique feature of the project is that it runs the kubernetes clusters on VirtualBox or libvirt so that you can use your own PC or laptop without incurring the cost of cloud. It creates kubernetes cluster according to the following criteria:

• certification type(default CKS, set via environment variable CERTIFICATION_TYPE)
• mock test set(default 01, set via environment variable MOCK_SET)
• question number(mandatory, set via environment variable QUESTION)

So if you wish to prepare a kubernetes cluster to solve the question 1 of the CKS '01' mock set, you lanuch the cluster as follows:

 QUESTION=1 MOCK_SET=01 CERTIFICATION_TYPE=CKS vagrant up

Due to limited resources on PC and laptop, you should remove existing cluster before creating a new one:

vagrant destroy

Otherwise, you will encounter error similar to the one that follows:

You are requesting cluster CKS-M01-C9(Q17), you have to destroy the existing cluster CKS-M01-C10(Q18) first!

To learn the current cluster, you run:

vagrant status

And you will get output like:

##################################################################
#                                                                #
#              Kubernetes cluster CKS-M01-C10(Q18)               #
#                                                                #
##################################################################
Current machine states:

master                    running (libvirt)
slave-1                   running (libvirt)
slave-2                   running (libvirt)

This environment represents multiple VMs. The VMs are all listed
above with their current state. For more information about a specific
VM, run `vagrant status NAME`.

which displays the certification type, mock set, cluster number and question nubmer as indicated in the parenthesis of the third line.

Pre-requisite

You need the following tools required by this project:

• libvirt(Linux) or Virtualbox(Windows/MacOS)
• Vagrant
• vagrant-libvirt
• vagrant-hostmanager
• Ansible

Although VirtualBox also works on Linux, it is recommended you use libvirt as it provisions virtual machines faster. Install these tools using the package manager of operating systems such as apt-get on Debian/Ubuntu or pacman on Arch Linux.

The vagrant-hostmanager is a vagrant plugin which enables you to access the kubernetes nodes using host name by creating entries in the /etc/hosts file on the host. To install this plugin, you type:

vagrant plugin install vagrant-hostmanager

If you use libvirt on Linux, you need the vagrant-libvirt plugin, which can be installed as follows:

vagrant plugin install vagrant-libvirt

Available test sets

Currently, there is very limited number of test set.

Type	Set	Questions	Link	notes
CKS	01	18	Test set spec

Launch a kubernetes certification cluster

Firstly, you clone this project. Open a command line window, nagivate to the root directory of this project. Then run the following commands if you use libvirt:

QUESTION=n vagrant up --provider=libvirt

Otherwise, run this command instead:

QUESTION=n vagrant up

Substitute the question number n with the one you are going to solve. If everything goes smoothly, the master and work nodes will be installed and configured automatically and mock test related setup will be conducted. In case the provision of master fails, you may trigger the setup by:

QUESTION=1 vagrant reload master --provision

Likewise, if the provision of work node fails for reasons such as network connectivity, you may re-run ansible as follows:

QUESTION=1 vagrant reload slave-? --provision

Substitute the question mark with the appropriate slave number.

kubectl setup

You need install kubectl on your laptop and copy the /tmp/kubeconfig, which is feteched from the master node, to ~/.kube/config or alternatively you set the KUBECONFIG environment variable as follows:

export KUBECONFIG=/tmp/kubeconfig

It is highly recommended that you setup alias k for kubectl to save typing. Follow the official kubernetes documentation to properly configure your environment.

notes on internet access and VPN

If you prepare the certification practice in an environnent where access to sites such as:

• docker.io
• pkgs.k8s.io
• github.com

is restricted and you have VPN as an alternative, you should make sure the MTU of the VPN matches the virtual machine and virtual NICs on which the kubernetes cluster in running. If your VPN or tunnel's MTU is lower than 1500, then you should configure the variables MTU and libvirt__mtu in the Vagrantfile appropriately. Otherwise, you will experience extreme slow network transmission or broken connections.