blog.lazkani.io-20200902-historical/posts/kubernetes/local-kubernetes-cluster-on-kvm.org

#+BEGIN_COMMENT
.. title: Local Kubernetes Cluster on KVM
.. date: 2019-02-17
.. updated: 2019-06-21
.. status: published
.. tags: kubernetes, rancher, rancheros, kvm, libvirt,
.. category: kubernetes
.. slug: local-kubernetes-cluster-on-kvm
.. authors: Elia el Lazkani
.. description: Deploying a kubernetes cluster locally on KVM.
.. type: text
#+END_COMMENT

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 [[https://rancher.com/docs/rancher/v2.x/en/quick-start-guide/deployment/quickstart-vagrant/][recommend]] /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 [[https://rancher.com/docs/os/v1.x/en/][requirements]], 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/ [[https://rancher.com/docs/os/v1.x/en/installation/running-rancheros/workstation/boot-from-iso/][ISO]] do the following.

#+BEGIN_EXPORT html
<div class="admonition note">
<p class="admonition-title">Note</p>
#+END_EXPORT
Because I was using /libvirt/, I was able to do =virsh console <vm>= and
run these commands.
#+BEGIN_EXPORT html
</div>
#+END_EXPORT

* Virsh Console
If you are running these VMs on /libvirt/, then you can console into the box and run =vi=.

#+BEGIN_EXAMPLE
 # virsh list
 Id   Name      State
 -------------------------
 21   kube01    running
 22   kube02    running
 23   kube03    running
 24   rancher   running

 # virsh console rancher
#+END_EXAMPLE

* Configuration
If you read the /RancherOS/ [[https://rancher.com/docs/os/v1.x/en/][documentation]], you'll find out that you can configure the /OS/ with a =YAML= configuration file so let's do that.

#+BEGIN_EXAMPLE
 $ vi cloud-config.yml
#+END_EXAMPLE

And that file should hold.

#+BEGIN_SRC 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
#+END_SRC

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.

After you save that file, install the /OS/.

#+BEGIN_EXAMPLE
 $ sudo ros install -c cloud-config.yml -d /dev/sda
#+END_EXAMPLE

Do the same for the rest of the servers and their names and IPs should be as follows (if you are following this tutorial):

#+BEGIN_EXAMPLE
 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
#+END_EXAMPLE

* 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.

#+BEGIN_EXAMPLE
 $ sudo vi /etc/hosts
#+END_EXAMPLE

#+BEGIN_EXAMPLE
 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
#+END_EXAMPLE

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 [[https://rancher.com/docs/rke/v0.1.x/en/][RKE]].
- 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.
First, =$ ssh rancher@192.168.122.5= then:

#+BEGIN_EXAMPLE
 [rancher@rancher ~]$ docker run -d --restart=unless-stopped -p 80:80 -p 443:443 rancher/rancher
#+END_EXAMPLE

Give it a few minutes for the container to come up and the application as well. Meanwhile configure your =/etc/hosts= file on your machine.

#+BEGIN_EXAMPLE
 192.168.122.5    rancher.kube.loco
#+END_EXAMPLE

Now that all that is out of the way, you can login to [[https://rancher.kube.loco]] and set your =admin= password and the =url= for Rancher.

* Deploying Kubernetes
Now that everything is ready, let's deploy /kubernetes/ the easy way.

At this point you should be greeted with a page that looks like the
following.

#+BEGIN_EXPORT html
<a class="reference" href="/images/local-kubernetes-cluster-on-kvm/01-add-cluster.png" alt="Add Cluster Page" align="center">
<img src="/images/local-kubernetes-cluster-on-kvm/01-add-cluster.thumbnail.png">
#+END_EXPORT
#+BEGIN_EXPORT html
</a>
#+END_EXPORT

Click on the *Add Cluser*

#+BEGIN_EXPORT html
<a class="reference" href="/images/local-kubernetes-cluster-on-kvm/02-custom-cluster.png" alt="Custom Cluster Page" align="center">
<img src="
/images/local-kubernetes-cluster-on-kvm/02-custom-cluster.thumbnail.png">
#+END_EXPORT
#+BEGIN_EXPORT html
</a>
#+END_EXPORT

Make sure you choose *Custom* as a /provider/. Then fill in the *Cluser Name* in our case we'll call it *kube*.

#+BEGIN_EXPORT html
<a class="reference" href="/images/local-kubernetes-cluster-on-kvm/03-calico-networkProvider.png" alt="Network Provider: Calico (Optional)">
<img src="/images/local-kubernetes-cluster-on-kvm/03-calico-networkProvider.thumbnail.png">
#+END_EXPORT
#+BEGIN_EXPORT html
</a>
#+END_EXPORT

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*.

#+BEGIN_EXPORT html
<a class="reference" href="/images/local-kubernetes-cluster-on-kvm/04-nginx-ingressDisabled.png" alt="Nginx Ingress: Disabled" align="center">
<img src="/images/local-kubernetes-cluster-on-kvm/04-nginx-ingressDisabled.thumbnail.png">
#+END_EXPORT
#+BEGIN_EXPORT html
</a>
#+END_EXPORT

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*.

#+BEGIN_EXPORT html
<a class="reference" href="/images/local-kubernetes-cluster-on-kvm/05-customize-nodes.png" alt="Customize Nodes" align="center">
<img src="/images/local-kubernetes-cluster-on-kvm/05-customize-nodes.thumbnail.png">
#+END_EXPORT
#+BEGIN_EXPORT html
</a>
#+END_EXPORT

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.

#+BEGIN_EXPORT html
<a class="reference" href="/images/local-kubernetes-cluster-on-kvm/06-registered-nodes.png" alt="Registered Nodes" align="center">
<img src="/images/local-kubernetes-cluster-on-kvm/06-registered-nodes.thumbnail.png">
#+END_EXPORT
#+BEGIN_EXPORT html
</a>
#+END_EXPORT

#+BEGIN_EXPORT html
<div class="admonition warning">
<p class="admonition-title">warning</p>
#+END_EXPORT
Do *NOT* click /done/ until you see all /3 nodes registered/.
#+BEGIN_EXPORT html
</div>
#+END_EXPORT

* 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.

#+BEGIN_EXPORT html
<a class="reference" href="/images/local-kubernetes-cluster-on-kvm/07-kubernetes-cluster.png" alt="Kubernetes Cluster" align="center">
<img src="/images/local-kubernetes-cluster-on-kvm/07-kubernetes-cluster.thumbnail.png">
#+END_EXPORT
#+BEGIN_EXPORT html
</a>
#+END_EXPORT

Welcome to your Kubernetes Cluster.

* Conclusion
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.