Kubernetes and the Erlang VM: orchestration on the large and the small, by José Valim

Thank you for sharing.

I am mulling the idea of writing an Elixir deployment book covering multiple deployment methods. Ansible will be used for server setup/deployment (build servers and run-time servers), then CI/CD deployment to Kubernetes was going to be covered in the second half. Initially I was going to aim for LeanPub for distribution. Wasn’t sure how many folks would be interested in such a book TBH.

I agree that comparing k8s and OTP is not apples to apples as these two works on different level. However with time I started to understood anti-systemd guys when I tried to learn how to operate k8s. It is big, it is hairy, it requires enormous amount of time to understand it correctly. K8s is nice when it isn’t your job to maintain it, but when you need to maintain it it became as easy as understanding Azathoth’s doings.

In my humble opinion using Elixir without k8s is much easier, as all I need is to spawn new VM with properly configured init system and I will get almost the same features as I have with k8s without all complications from k8s.

Me! Just do it, now!

I’d suggest trying not to go into ansible and server setup. That is a large topic in itself which will distract from the main topic.

I think there are 2 audiences (well really 3 but the third can look elsewhere for details on setting up servers with ansible, since that is not specific to Elixir): 1) those who need to run small projects and act as the main ops person as well – likely good enough to discuss how to use with systemd in their case 2) those at a company who need to fit into the existing organizations infrastructure.

The direction we are going with adoptingerlang.org is to mainly cover (2) when the organization is using kubernetes. The systemd case is covered in an appendix.

Since your book is solely about deployment I wouldn’t restrict to just k8s like adoptingerlang but just like we don’t cover setting up k8s (besides pointing to dev tools like microk8s and to google kubernetes engine for prod) I’d warn against it becoming an operations book instead of an Elixir book

Thank you for the feedback! I now think jumping in with ansible first would be out of scope although if time permits I will cover it in its own section last. Starting with the basics of compiling/building a release and running the release on a server appears to solve a number of questions about Elixir.

What tooling are you using for adoptingerlang.org?

The tooling for writing and publishing? It is a Hugo site hosted on netlify (which is great for CI because it has a “preview” deploy feature that gives us a live url for every PR) and written in org-mode GitHub - adoptingerlang/adoptingerlang: Adopting Erlang is an ongoing effort to gather all the resources that will help you use Erlang in a business · GitHub. There is an Emacs tool ox-hugo that converts from org-mode to hugo, but the org-mode is also converted to a pdf.

Sometimes Ansible is used for both server provisioning and also for distributing upgrades and restarting services.

True. A chapter on using ansible for deploying, unpacking, starting/upgrading a release might be good.

Another suggestion, stick to what you actually use. If you (frigidcode) have experience with production ansible deloyment then maybe don’t also include a puppet/chef chapter. You could instead get collaborators who do use puppet or chef (or one of the many other offerings) to write those chapters.

The reason being, those who have used these tools in anger will know bits that are important to highlight – though obviously need someone who isn’t experienced with these tools to do a review because someone experienced will also accidentally leave out plenty of useful information that someone new will need.

Not to say writing and publishing guides while learning a tool isn’t really useful, I’m just referring explicitly to a book about real world production deployment, as opposed to a “getting up and running with Puppet and Elixir” post.

Agreed, I only planned on writing about what I used in anger