When writing services that accept TCP connections, we tend to think of our work as starting from the point where our service accepts a new client connection and finishing when we complete the request and close the socket. For services at scale, operations can happen at such a high rate that some of the default resource limits of the Linux kernel can break this abstraction and start causing impact to incoming connections outside of that connection lifecycle. This post focuses on some standard resource limitations that exist before the client socket is handed to the application.

Explain how IPTables, Chains and Rules work together.

Dig into container. Docker image are just tar file with some meta data. A container needs at least: network stack, file system, processes. So how can we re-create that, using simple bash commands?

In The Pragmatic Programmer, Andrew Hunt and David Thomas introduced the DRY (Don’t Repeat Yourself) principle But then Sandi Metz came along and said: Duplication is far cheaper than the wrong abstraction. So what should we do

B-Tree index is the default index. But you know we have no one size fit all data structure for fast look up. What if we just want an exact match? Well, a hash index might faster there.

I have been reviewing more JS code recently and saw this a lot. Here, Ben Nadel shows why they aren’t needed and when they are needed(In a comment though).

Hey email app is getting a lot of attention recently. Partly because it is created by DHH, creator of Ruby on Rails, who has a strong opinion on avoiding SPA JavaScript and focus a lot on Ruby. He used to avoid public cloud like AWS or GCP and belive it’s more cost effective on bare metal. But in one podcast I heard 2 years ago, he hinted that eventually the cloud will be cheaper enough and it makes sense to use cloud by then. Here, we will see their infrastructure, initially starting with GCP, then migrate to AWS EKS. They made use a lot of managed service

A guide to setup SSH authentication with certificates instead of pub key. Why? Certificate allow you to set expiration date, centralization control and revoke easily. With normal public key, once got in, users can added their own key and do whatever they want.

teaches how to use the command-line utility jq to filter and parse complex JSON files into flat CSV files. If you need a play ground for jq, check out jqplay.

The author wants it to be the best book in this field. It’s free to read online right now on Manning so check it out(You have to register for a free account to read though). It has 11 chapters so far. Learning about cryptography definetely help you along the way to understand thing like TLS, PGP etc