Today a coworker of mine asked if I have a 5 minute overview of Kubernetes and I referred him to one of my older posts Containers for the vSphere Admin: After School Special Update and I noticed a lot has changed since then. So instead of updating that post, because I think we need a historical archive so we know what happened, I am writing this one.
Let’s start at the very beginning, a very good place to start
A pre-req to this post is a good understanding of containers. The post I wrote a while ago is still relevant with some recent updates. If you need to quickly understand containers go read Containers for the vSphere Admin and come back here. Welcome back, now to update that post there is now containerd. Both Docker and Kubernetes use containerd.
What is containerd? An industry-standard container runtime with an emphasis on simplicity,robustness and portability. An industry-standard container runtime with an emphasis on simplicity, robustness, and portability.
What is Docker? Enterprise Container Platform for High-Velocity Innovation. The Docker Platform is the industry-leading container platform for continuous, high-velocity innovation, enabling organizations to seamlessly build and share any application — from legacy to what comes next — and securely run them anywhere.
The Rise of the Container Scheduler: Kubernetes is here!
Tanzu is a portfolio of products that help to manage kubernetes environments both running on VMware based clouds (VMware VCF and VMware Cloud on AWS) as well as native public clouds like AWS EC2 and Azure. This guide is specifically focusing on Tanzu for vSphere. Tanzu is a commercially supported distribution of Kubernetes. To understand Tanzu for vSphere you need to understand how Kubernetes works.
As a former vSphere admin I alway liked analogy’s to understand new technology. So I will use vSphere here to explain Kubernetes. Ok, they are not exactly apples to apples but hopefully you get the comparison. Docker is the container run time engine and Kubernetes is a container scheduler that places containers on available hosts in a Kubernetes Cluster.
So essentially kubernetes is a container scheduler. Kubernetes schedules containers to run on what are called pod VM’s these are either Linux or Windows based virtual machines that are configured to listen to the kubernetes API for requests to pull a container image and run it. Multiple pod VM’s can form a cluster. Similar to vSphere HA, kubernetes can restart containers on surviving pod VM’s in the cluster if a pod VM goes down or fails for whatever reason.
Tanzu for vSphere is here!
With Tanzu, VMware built Kubernetes into vSphere. This allows you to provision and manage kubernetes clusters from the same tools you already know and love without learning something new. If you are looking to understand some of the general concepts of kubernetes and Tanzu see my guide here Project Pacific K8S explained in Amazon EC2 terms
vSphere with Tanzu allows you to manage containers and kubernetes in the vSphere client