OpenEBS: cStor storage engine on KVM

OpenEBS provides a Kubernetes native distributed storage solution which is friendly on developers and administrators. It is completely open source and part of the CNCF. Previously I wrote about installing and using OpenEBS, Jiva storage engine, on the Charmed Kubernetes distribution of Canonical. The Jiva storage class uses storage inside managed pods. cStor however can use raw disks attached to Kubernetes nodes. Since I was trying out Kubespray (also a CNCF project) on KVM and it is relatively easy to attach raw storage to KVM nodes, I decided to give cStor a try. cStor (which uses ZFS behind the scenes) is also the more recent and more robust storage engine and suitable for more serious workloads. See here. You can download the scripts I used to setup my Kubernetes environment here.

Production ready Kubernetes on your laptop. Kubespray on KVM

There are various options to install a production-like Kubernetes distribution on your laptop. Previously I tried out using the Canonical stack (Juju, MAAS, Charmed Kubernetes) for this. This worked nicely but it gave me the feeling that it was a bit Canonical specific and with the recent discussions around Snaps and the Canonical Snap Store, I decided to take a look at another way to install Kubernetes on my laptop in such a way that it would approximate a production environment. Of course first I needed to get my virtual infrastructure ready (KVM hosts) before I could use Kubespray to deploy Kubernetes. My main inspirations for this were two blog posts here and here. Like with Charmed Kubernetes, the installed distribution is bare. It does not contain things like a private registry, distributed storage (read here) or load balancer (read here). You can find my scripts here (which are suitable for Ubuntu 20.04).

Quick and easy: A multi-node Kubernetes cluster on CentOS 7 + QEMU/KVM (libvirt)

Kubernetes is a popular container orchestration platform. As a developer understanding the environment in which your application is going to run is important since this can help you use available services of the platform and fix issues.

There are several options to run Kubernetes locally to get some experience with Kubernetes as developer. For example Minikube, MicroK8s and MiniShift. These options however are not representative for a real environment. They for example usually do not have master and slave nodes. Running locally requires quite different configuration compared to running multiple nodes in VMs. Think for example about how to deal with storage and a container registry which you want to share over the different nodes. Installing a full blown environment requires a lot of work and resources. Using a cloud service usually is not free and you usually have less to no control over the environment Kubernetes is running in.

In this blog I'll describe a 'middle way'. Get an easy to manage small multi node Kubernetes environment running in different VMs. You can use this environment for example to learn what the challenges of clusters are and how to deal with them efficiently.

It uses the work done here with some minor additions to get a dashboard ready.

Minikube on KVM on Linux Mint 19.1

In a previous blog post I wrote about running Minikube on Windows. I ended with the suggestion that getting Minikube working might be much easier on Linux. Thus I installed Linux Mint (as dual-boot) on my laptop and gave it a shot. The steps I took to get it working are described here.