#+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

Note

#+END_EXPORT Because I was using /libvirt/, I was able to do =virsh console = and run these commands. #+BEGIN_EXPORT html
#+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 #+END_EXPORT #+BEGIN_EXPORT html #+END_EXPORT Click on the *Add Cluser* #+BEGIN_EXPORT html #+END_EXPORT #+BEGIN_EXPORT html #+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 #+END_EXPORT #+BEGIN_EXPORT html #+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 #+END_EXPORT #+BEGIN_EXPORT html #+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 #+END_EXPORT #+BEGIN_EXPORT html #+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 #+END_EXPORT #+BEGIN_EXPORT html #+END_EXPORT #+BEGIN_EXPORT html

warning

#+END_EXPORT Do *NOT* click /done/ until you see all /3 nodes registered/. #+BEGIN_EXPORT html
#+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 #+END_EXPORT #+BEGIN_EXPORT html #+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.