System administration is a special are of IT. It also has a special place in my heart. It is an interesting mixture of all the other disciplines, both common across the whole industry, and at the same time unique for each person, company, and geographical location. When I have something to say or share about system administration, I use this category.
If you ever tried listing a directory with a lot (10,000+) of files in it, I’m sure you know how annoyingly slow ‘ls’ can be. Turns out there is a simple way to make it better. Have a look at the “When setting an environment variable gives you a 40x speedup” blog post.
Or just do the following:
export LS_COLORS='ex=00:su=00:sg=00:ca=00:'
This will disable colors on the executable files, setuid/setgid bits, and capabilities.
Komiser is a really nice tool that provides an overview of your Amazon AWS setup. After a super simple install, you’ll have a web console which visualizes your AWS regions and the resources you run in them. It’s great for getting a quick overview, as well as for some analyses of billing, security and utilization issues.
aws-securitygroup-grapher is a handy tool that can generate a variety of graphs visualizing Amazon Security Groups. It is implemented as an Ansible role and uses GraphViz to produce the results.
This is particularly useful when you need to get familiar with a complex VPC setup by someone else, or when you want to review the results of an automated setup.
“Packets-per-second limits in EC2” is an interesting dive into network limits on the Amazon EC2. Even if you aren’t hitting any limits yet, this article provides plenty of useful information, including benchmarking tools and quick reference links for Enhanced Networking.
The conclusion of the article is:
By running these experiments, we determined that each EC2 instance type has a packet-per-second budget. Surprisingly, this budget goes toward the total of incoming and outgoing packets. Even more surprisingly, the same budget gets split between multiple network interfaces, with some additional performance penalty. This last result informs against using multiple network interfaces when tuning the system for higher networking performance.
The maximum budget for m5.metal and m5.24xlarge is 2.2M packets per second. Given that each HTTP transaction takes at least four packets, we can translate this to a maximum of 550k requests per second on the largest m5 instance with Enhanced Networking enabled.
Intermediate Vim is a nice collection of Vim tips and tricks, which are aimed at somebody who is already familiar with Vim. (There is of course no single definition of what’s advanced, intermediate or introductory, so we’ll leave that argument out.) But the article is well worth the read, even if you already know all of the mentioned commands. A refresher is always welcome.