.. description: Deploying a kubernetes cluster locally on KVM.
.. type: text
I wanted to explore *kubernetes* even more for myself and for this blog. I've worked on pieces of this at work but not the totality of the work which I would like to understand for myself. I wanted, also to explore new tools and ways to leverage the power of *kubernetes*.
So far, I have been using *minikube* to do the deployments but there is an inherit restriction that comes with using a single bundled node. Sure, it is easy to get it up and running but at some point I had to use ``nodePort`` to go around the IP restriction. This is a restriction that you will have in an actual *kubernetes* cluster but I will show you later how to go around it. For now, let's just get a local cluster up and running.
.. TEASER_END
Objective
=========
I needed a local *kubernetes* cluster using all open source tools and easy to deploy. So I went with using *KVM* as the hypervisor layer and installed ``virt-manager`` for shallow management. As an OS, I wanted something light and made for *kubernetes*. As I already know of Rancher (being an easy way to deploy *kubernetes* and they have done a great job so far since the launch of their Rancer 2.0) I decided to try *RancherOS*. So let's see how all that works together.
Requirements
============
Let's start by thinking about what we actually need. Rancher, the dashboard they offer is going to need a VM by itself and they `recommend <https://rancher.com/docs/rancher/v2.x/en/quick-start-guide/deployment/quickstart-vagrant/>`_*4GB of RAM*. I only have *16GB of RAM* on my machine so I'll have to do the math to see how much I can afford to give this *dashboard* and *manager*. By looking at the *RancherOS* hardware `requirements <https://rancher.com/docs/os/v1.x/en/>`_, I can tell that by giving a each node *2GB* of RAM I should be able to host a *3 node cluster* and with *2* more for the *dashboard* that puts me right on *8GB of RAM*. So we need to create *4 VMs* with *2GB of RAM* each.
Installing RancherOS
====================
Once all 4 nodes have been created, when you boot into the *RancherOS*`ISO <https://rancher.com/docs/os/v1.x/en/installation/running-rancheros/workstation/boot-from-iso/>`_ do the following.
..note::
Because I was using *libvirt*, I was able to do ``virsh console <vm>`` and run these commands.
Virsh Console
=============
If you are running these VMs on *libvirt*, then you can console into the box and run ``vi``.
..code:: text
# virsh list
Id Name State
-------------------------
21 kube01 running
22 kube02 running
23 kube03 running
24 rancher running
# virsh console rancher
Configuration
=============
If you read the *RancherOS*`documentation <https://rancher.com/docs/os/v1.x/en/>`_, you'll find out that you can configure the *OS* with a ``YAML`` configuration file so let's do that.
..code:: text
$ vi cloud-config.yml
And that file should hold.
..code:: yaml
---
hostname: rancher.kube.loco
ssh_authorized_keys:
- ssh-rsa AAA...
rancher:
network:
interfaces:
eth0:
address: 192.168.122.5/24
dhcp: false
gateway: 192.168.122.1
mtu: 1500
Make sure that your **public***ssh key* is replaced in the example before and if you have a different network configuration for your VMs, change the network configuration here.
Do the same for the rest of the servers and their names and IPs should be as follows (if you are following this tutorial):
..code:: text
192.168.122.5 rancher.kube.loco
192.168.122.10 kube01.kube.loco
192.168.122.11 kube02.kube.loco
192.168.122.12 kube03.kube.loco
Post Installation Configuration
===============================
After *RancherOS* has been installed, one will need to configure ``/etc/hosts`` and it should look like the following if one is working off of the *Rancher* box.
..code:: text
$ sudo vi /etc/hosts
..code:: text
127.0.0.1 rancher.kube.loco
192.168.122.5 rancher.kube.loco
192.168.122.10 kube01.kube.loco
192.168.122.11 kube02.kube.loco
192.168.122.12 kube03.kube.loco
Do the same on the rest of the servers while changing the ``127.0.0.1`` hostname to the host of the server.
Installing Rancher
==================
At this point, I have to stress a few facts:
- This is not the Rancher recommended way to deploy *kubernetes*.
- The recommended way is of course `RKE <https://rancher.com/docs/rke/v0.1.x/en/>`_.
- This is for testing, so I did not take into consideration backup of anything.
- There are ways to backup Rancher configuration by mounting storage from the ``rancher`` docker container.
If those points are understood, let's go ahead and deploy Rancher.
Optionally, you can choose your **Network Providor**, in my case I chose **Calico**. Then I clicked on **show advanced** at the bottom right corner then expanded the *newly shown tab***Advanced Cluster Options**.
We will disable the **Nginx Ingress** and the **Pod Security Policy Support** for the time being. This will become more apparent why in the future, hopefully. Then hit **Next**.
Make sure that you select all **3 Node Roles**. Set the **Public Address** and the **Node Name** to the first node and then copy the command and paste it on the *first* node.
Do the same for *all the rest*. Once the first docker image gets downloaded and ran you should see a message pop at the bottom.
Do **NOT** click *done* until you see all *3 nodes registered*.
Finalizing
==========
Now that you have *3 registered nodes*, click **Done** and go grab yourself a cup of coffee. Maybe take a long walk, this will take time. Or if you are curious like me, you'd be looking at the logs, checking the containers in a quad pane ``tmux`` session.
After a long time has passed, our story ends with a refresh and a welcome with this page.
At this point, you can check that all the nodes are healthy and you got yourself a kubernetes cluster. In future blog posts we will explore an avenue to deploy *multiple ingress controllers* on the same cluster on the same ``port: 80`` by giving them each an IP external to the cluster.
But for now, you got yourself a kubernetes cluster to play with. Enjoy.
