Boostnote is yet another alternative for taking notes. This one is an Open Source and is built for developers. Some of the features – Markdown support, search, cross-platform, works offline.
There is also Boostnote Team edition for, you know, teams.
Here are some exciting news from the BitBucket Pipelines blog: Bitbucket Pipelines now supports building Docker images, and service containers for database testing.
We developed Pipelines to enable teams to test and deploy software faster, using Docker containers to manage their build environment. Now we’re adding advanced Docker support – building Docker images, and Service containers for database testing.
Vidar Hokstad explains what systemd units are and how to write them. Very useful for that day when I will stop hating systemd and will try to embrace it.
Systemd has become the defacto new standard init for Linux-based systems. While not everyone has made the switch yet, pretty much all the major distros have made the decision to switch.
For most people this has not meant all that much yet, other than a lot of controversy. Systemd has built in SysV init system compatibility, and so it’s possible to avoid dealing with it quite well.
But there is much to be gained from picking up some basics. Systemd is very poweful.
I’m not going to deal with the basics of interacting with systemd as that’s well covered elsewhere. You can find a number of basic tips and tricks here.
Instead I want to talk about how to write systemd units.
Doug Vitale Tech Blog runs a post with a collection of the deprecated Linux networking commands and their replacements. Pretty handy if you want update some of your old bash scripts.
||ip n (ip neighbor)
||ip a (ip addr), ip link, ip -s (ip -stats)
||ip link, ifrename
||ss, ip route (for netstat-r), ip -s link (for netstat -i), ip maddr (for netstat-g)
||ip r (ip route)
CSV, or comma-separated values, is a very common format for managing all kinds of configurations, as well data manipulation. As the linked Wikipedia page mentions, there are a few RFCs that try to standardize the format. However, I thought, there is still a lack of schema-type standard that would allow one to define a format for particular file.
Today I came across an effort that attempts to do just that – CSV Schema Language v1.1 – an unofficial draft of the language for defining and validating CSV data. This is work in progress by the Digital Preservation team at The National Archives.
Apart from the unofficial draft of the language, there is also an Open Source CSV Validator v1.1 application, written in Scala.
Federacy has an interesting research in Docker image vulnerabilities. The bottom line is:
24% of latest Docker images have significant vulnerabilities
This can and should be improved, especially given the whole hierarchical structure of Docker images. It’s not like improving security of all those random GitHub repositories.
In “Why Configuration Management and Provisioning are Different” Carlos Nuñez advocates for the use of specialized infrastructure provisioning tools, like Terraform, Heat, and CloudFormation, instead of relying on the configuration management tools, like Ansible or Puppet.
I agree with his argument for the rollbacks, but not so much for the maintaining state and complexity. However I’m not yet comfortable to word my disagreement – my head is all over the place with clouds, and I’m still weak on the terminology.
The article is nice regardless, and made me look at the provisioning tools once again.
Here are a couple of useful Bash resources that came upon my radar recently.
First one is Julia Evans’ blog post “Bash scripting quirks & safety tips“. It’s quite introductory, but is has a few useful tips. The one in particular I
either didn’t know about or completely forgot mentioned recently is on how to make Bash scripts safer by using “set -e“, “set -u“, and “set -o pipefail“. These go well with another post of mine not so long ago.
The second is Sam Rowe’s blog post “Advancing in the Bash Shell“, which I found useful for all kinds of navigation and variable expansion in Bash command line. Especially the bits on searching and reusing the history.
OpenWrt, which is a Linux distribution for embedded devices, website has a really handy HowTo on Network Traffic Control (QOS).
Traffic Control is the umbrella term for packet prioritizing, traffic shaping, bandwidth limiting, AQM (Active Queue Management), QoS (Quality of Service), etc. This HowTo will help you understand and set up traffic control on your router. It is one strategy to address problems caused by Network congestion.
It covers the tc (traffic control) and iptables commands, and much more.
Jessie Frazelle reiterates her point on containers in the blog post “Setting the Record Straight: containers vs. Zones vs. Jails vs. VMs“:
The Design of Solaris Zones, BSD Jails, VMs and containers are very different.
Solaris Zones, BSD Jails, and VMs are first class concepts. This is clear from the Solaris Zone Design Spec and the BSD Jails Handbook. I hope it can go without saying that VMs are very much a first class object without me having to link you somewhere :P.
Containers on the other hand are not real things.
A “container” is just a term people use to describe a combination of Linux namespaces and cgroups. Linux namespaces and cgroups ARE first class objects. NOT containers.