ryuheechul

personal micro wiki of DevOps

History/Background

• https://devops.com/why-did-devops-become-so-popular-3-theories/
• https://devops.com/the-origins-of-devops-whats-in-a-name/
• https://devops.com/definition-devops-masses/

ryuheechul

• Cluster Ready Checklist for Kubernetes
• Application Checklist for Kubernetes
• Kubernetes failure stories
  • the conntrack race issue and workaround

ryuheechul

Why?

• Sometimes I want to develop just the logic or the flow of apps not the implementations.
• I wanted to prototype with "simpler" code.
• It would be nice to see working without actually writing real code yet.

ryuheechul

A play ground to complete this doc

ryuheechul

After a while since I discovered Functional Reactive Programming, I believe this is the way Keytty should be built.

Articles that convinced me

• https://gist.github.com/staltz/868e7e9bc2a7b8c1f754
• https://cycle.js.org/streams.html

Currently, Keytty is mostly made up with proactive OOP written in Objective C.

There are several issues that I found when I try to maintain the code and add more features. such as:

• Controller has too many responsibilities and gets more complex over time.

ryuheechul

/\bHTTP_(?!HOST\b)(.)+/g

HTTP_HOST // not match
HTTP_NOTHOST // match
HTTP_HOSTS // match
HTTP_hHOST // match
HTTP_HOST_3 // match

ryuheechul

I just turned age 36 (by Korean standards) and noticed that some of my friends seem to be sad to have such a "big" number as their age.

So I thought about whether there could be anything special about the number 36 and I found a simple and interesting pattern for that number.

When you divide 36 by 2, the answer is 18 (36 / 2 == 18); and when you multiply each digit of 36 individually, the answer is also 18 (3 * 6 == 18)!

So it seemed kind of special to me and then I wondered if there is any natural number that has these same features (except 0)

As a non-math person, the shocking discovery was that 36 seems to be the only number under 10M.

ryuheechul

prctl - Probe and Resource ConTroL (for k8s)

Just an Gist idea for now

Why?

• It's mundane to edit every Deployment in your k8s cluster to have your desired state for Liveness/Readiness Probe and Resources for each container
• Manaul operations also don't help collaborations of discussions to have right values for the states

How this would be better than manual approach?

• One(ish) place to read and edit desired states
• Keep alerting if the state of the container is different than the repository linked

ryuheechul

/* this works */
"1=2=3"
  |> Js.String.split("=")
  |. Js.log;

/* this works, too */
"1=2=3"
  -> Js.log;

/* but the code below doesn't */

ryuheechul

Claim: Difficulty with interop with JS when accepting nested object param from JS to Reason

Reasonml Ver: 3.3.2

• No problem with taking parameters from JS and matching to any type contains optional with one depth

• But it seems to lose values wrapped by option if you have more depth like below