.. 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: Elijah Lazkani .. 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 `_ *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 `_, 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 `_ do the following. .. note:: Because I was using *libvirt*, I was able to do ``virsh console `` 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 `_, 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. After you save that file, install the *OS*. .. code:: text $ sudo ros install -c cloud-config.yml -d /dev/sda 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 `_. - 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: .. code:: text [rancher@rancher ~]$ docker run -d --restart=unless-stopped -p 80:80 -p 443:443 rancher/rancher 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. .. code:: text 192.168.122.5 rancher.kube.loco 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. .. thumbnail:: /images/local_kubernetes_cluster_on_kvm/01-add_cluster.png :alt: Add Cluster Page Click on the **Add Cluser** .. thumbnail:: /images/local_kubernetes_cluster_on_kvm/02-custom_cluster.png :align: center :alt: Custom Cluster Page Make sure you choose **Custom** as a *provider*. Then fill in the **Cluser Name** in our case we'll call it **kube**. .. thumbnail:: /images/local_kubernetes_cluster_on_kvm/03-calico_networkProvider.png :align: center :alt: Network Provider: Calico (Optional) 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**. .. thumbnail:: /images/local_kubernetes_cluster_on_kvm/04-nginx_ingressDisabled.png :align: center :alt: Nginx Ingress: Disabled 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**. .. thumbnail:: /images/local_kubernetes_cluster_on_kvm/05-customer_nodes.png :align: center :alt: Customize Nodes 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. .. thumbnail:: /images/local_kubernetes_cluster_on_kvm/06-registered_nodes.png :align: center :alt: Registered Nodes .. warning:: 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. .. thumbnail:: /images/local_kubernetes_cluster_on_kvm/07-kubernetes_cluster.png :align: center :alt: Kubernetes Cluster 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.