I decided to recommission decent spec desktop (16 core – Threadripper 1950x, 32GB RAM) into a server of VMs. With the first project to be to build out a HA Kubernetes cluster. Why? When you can get a Kubernetes cluster in a click from a cloud vendor? For fun and to learn! This blog series will take you through the journey of building out the cluster.
To start on the project I decided to use VMware’s ESXI to host the VMs. For those who don’t know ESXI is an OS that only exists to allow you to serve VMs. If you want the full blown product it is very expensive but luckily you can get it for FREE from VMware, simply by registering for a free license and added once installed. There are a couple of limitations on the free license but none that will get in the way of most hobbiests. The limitations are you can only have 2 real CPUs in your VMs and as most people are going to put this on a single machine that won’t matter and the way backups are of the whole fleet of VMs is restricted, again this is not a concern for me. So for free this is a pretty good deal.
To install, I simply downloaded the x86 64bit ISO and put it on a USB drive using BalenaEtcher. Then simply boot from the USB drive and hit next a few times through the ESXI install. Once installed a web url is displayed showing the IP address of the machine, that is how you interact with ESXI. The UI is a bit 1990s but remember we are talking about a free license here!
For the cluster VMs I decided to use Ubuntu 20.04 LTS server edition. For my use case I don’t need the added bloat that comes with desktop Ubuntu. I created a new VM and attached the Ubuntu ISO and ran through the installer. What is very cool is the default way ESXI sets up the VMs is that it makes them available on the main network. So for example in my home network I’m using 192.168.1.1/24 and the VMs get an IP address in that CIDR. That means that from another machine when you SSH into the VM you don’t even know that its a VM, you can treat it like any other machine on the network. ESXI setups up a virtual switch on routes traffic through the host machine to the VM automatically.
I named my first machine master01 as for my HA Kubernetes cluster I’m going to build out 3 master nodes to run the control plane and 3 worker nodes. Once the first machine is up and running there is a really easy way to create the other 5. Simply shutdown the VM and then clone it, this Youtube video explains how to clone a VM so I’m not going to repeat the instructions here.
Once all 6 machines have been created, there are a few things we need to do to tidy them up. Firstly, I wanted them all to have sequential IPs in my network so I would remember where they were. To do this we simply need to edit the file /etc/netplan/00-installer-config.yaml to something like the following:
network:
ethernets:
ens160:
dhcp4: false
addresses: [192.168.1.202/24]
gateway4: 192.168.1.1
nameservers:
addresses: [8.8.8.8,8.8.4.4]
version: 2
In the above configuration we are setting the static IP of the machine to 192.168.1.202 with a default gateway of 192.168.1.1 to make this config apply run sudo netplan apply. The next thing we need to do is rename the machines, as currently they all have the same hostname as the copied VM. To do this first we update the hostname in /etc/hostname and then update any reference to the old machine name in /etc/hosts to the new one. With those changes in place we need to reboot to make them apply.
Lastly to make the machines easier to work with, I setup the /etc/hosts file on my laptop to the following:
192.168.1.200 master01
192.168.1.201 master02
192.168.1.202 master03
192.168.1.203 worker01
192.168.1.204 worker02
192.168.1.205 worker03
This means that we can SSH into each machine using a friendly name rather than the IP address.
And with that we now have our 6 machines ready to go, in part 2 we will get on to installing Kubernetes…
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