Want to learn Kubernetes but don’t know where to start? I was in the same boat, and after reading numerous Kubernetes tutorials, I realized there had to be an easier way for beginners to learn.
Having recently joined LogDNA, I’m going to share what I learned in the past two weeks, as well as the best resources I found – comics, guides, tutorials – all so you can go from zero to Kubernetes expert in no time.
Full disclosure, I started out building php and wordpress sites long ago, and I am mostly familiar with “ancient” self hosted monolithic applications. I’m a newbie when it comes to containers and container orchestration.
Surprisingly, of all resources, it was through a series of comics that I found my bearings of what Docker containers and Kubernetes is. The first and best was created by Google: Smooth Sailing with Kubernetes. I highly recommend reading this first.
What Are Containers?
The most familiar reference that I have to compare containers to are Virtual Machines. Virtual Machines offer isolation at the hardware level, where a server offers guest operating systems to run on top of it. Not only VMWare but Microsoft Hyper-V, Citrix XenServer, and Oracle VirtualBox all with Hypervisors that enabled hardware virtualization and let each guest OS have access to CPU, memory and other resources. The limitations with VM was that each guest operating system had a large footprint of its own full OS image, memory and storage requirements. So scaling them was costly and the applications weren’t portable between hosting providers, and private/public clouds.
Containers sit on top of the physical hardware and its host operating system to share the host OS’ kernel, binaries, and libraries. This way they’re much more light weight with image sizes in the megabytes instead of gigabytes and can start up in seconds rather than minutes. Along with obvious performance benefits, they also reduce management overhead of updating and patching full operating systems and they’re much more portable to different hosting providers. Multiple containers can run on a single host OS which saves operating costs.
Consolia’s comic offers a great visualization of the difference between VM and Containers: https://consolia-comic.com/comics/containers-and-docker
And xkcd offers offers some humor on containers.
Docker wanted to allow developers to create, deploy and run applications through the use of containers. With Docker containers, they focused on faster deployment speeds, application portability, and reuse. Docker does not create an entire virtual operating system and will require that the components that are not already on the host OS to be packaged inside the container. Applications will be packaged up with exactly what they need to run, no more and no less.
Some interesting information on Docker containers and how incredibly quickly they’ve been adopted around the world:
- It was only released in 2014
- Over 3.5M applications have been placed in containers using Docker
- 37B containerized apps have been downloaded so far
What is Kubernetes?
This Illustrated Children’s Guide to Kubernetes is really good at explaining the need for Kubernetes.
Google created and open sourced the Kubernetes orchestration system for docker containers. It is used to automate the deployment, scaling and management of containerized applications.
Google runs over 2 billions containers per week and built Kubernetes to be able to do so at worldwide scale.The idea is to provide tools for running distributed systems in production like load balancing, rolling updates, resource monitoring, naming and discovery, auto-scaling, mounting storage systems, replicating application instances, checking the health of applications to log access, and support for introspection.
Kubernetes allows developers to create and manage clusters and scale them. Brian Dorsey’s talk at GOTO 2015 helped get from concept to seeing a real life example of deployment, replication and updates within an hour.
Side note, I’m currently reading Google’s SRE book and awe-struck by their story of scaling up.
How to Get Started
I started with the official docs of Kubernetes Basics And then followed this Hello World Mini Kubes tutorial. I’m just making my way through this excellent tutorial now called Kubernetes the Hard Way.
So far, now that I have a basic understanding of Containers and Kubernetes, I’m really excited at all its possibilities. It’s incredible to see that such powerful tools are available to all, both for developers to do CI/CD and especially for devops to scale, maintain 24/7 availability regardless of what happens and get a good night’s rest without alerts of catastrophic failures.
I’m also realizing that using Kubernetes also requires the use of other additional tools like Helm for managing Kubernetes packages and expedites the need for centralized logging and monitoring tools. It’s not as simple as logging into a server to look at a log file anymore when you’re dealing with many replicas and nodes that start and stop on the fly. As you come up with your Kubernetes logging strategy, here are some key Kubernetes metrics to log. It’s cool to see how LogDNA solves this integration with Kubernetes better than any other log management solution in the market. You have a choice of doing this yourself or get up and running with just two lines.