cron.weekly issue #22: Debian 8.4, Containers at Google, certdiff, netdata, uphold & many more!

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Mattias Geniar, April 03, 2016

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Welcome to cron.weekly edition 22 for Sunday, April 3rd.

Lots of new tools in this release and plenty of reading material on Linux and open source.



There is no “my” in open source

An interesting read on how you can’t “take down open source”, like the case of NodeJS’s package problems last week. It’s open source, therefore is open for everyone. The code is “of the people”, not something a single person can undo.

Linux 4.6 To Offer Faster Raspberry Pi 3D Performance

Good news for Raspberry Pi users in the upcoming 4.6 kernel!

A Decade Of Container Control At Google

A lengthy read to understand some of the history of container usage at Google. It also offers more insights into why Google created and open sourced Kubernetes, their container management system.

Containers are not VMs

A very good reminder to stop treating Docker containers as VMs: the underlying architecture is fundamentally different between a “container” and a “VM”.

Linux Wallpapers That Are Also Cheat Sheets

If you like informational wallpapers, these are very useful.

Why You Should Use (openSUSE) Tumbleweed

This article attempts to compare openSUSE to more ‘traditional’ distributions like Fedora or Ubuntu. And more specifically, openSUSE Tumbleweed, which looks more like Arch Linux. Very bleeding edge, constant updates, highly volatile.

Linux at 25: Q&A With Linus Torvalds

An interview with Linus Torvalds about the past, present and future of Linux. The original Linux was born in 1991, it’s turned 25 this year.

The largest unplanned outage in years and how we survived it

A month ago CSC’s high-performance computing services suffered the largest unplanned outage in years. In total approximately 1.7 petabytes and 850 million files were recovered.

Ubuntu on Windows — The Ubuntu Userspace for Windows Developers

This is pretty big news: the Ubuntu userspace is coming, natively, to Windows 10. This means you get a native /bin/bash shell, access to tools like ‘lsof’, ‘ps’, ‘grep’, ‘awk’, … right from a Windows command prompt. This should make managing a Windows server a lot easier for us Linux admins. A couple of screenshots show what that looks like.

An init system in a Docker container

A quest on getting systemd in Docker to have an init system that provides more flexibility to the user, instead of falling back to Supervisor whenever you want to run more than one job inside a container.

Xamarin for Everyone

Xamarin has gone full open source: this tool allows you to write C# code and have it transcoded to native iOS, Android, Windows, …

No-Cost RHEL Developer Subscription now available

Red Hat announced the availability of a no-cost Red Hat Enterprise Linux developer subscription, available as part of the Red Hat Developer Program.

Tools & Projects


This new tool is a fork of Caddy, the webserver written in Go. However, CoreDNS focusses on the DNS side by “chaining middleware”: a very simple configuration to perform powerful DNS configurations, zone forwarding, …


If you’ve ever tried to ‘diff’ 2 encoded certificate files, you know it’s not that easy. Certdiff decodes the certificates on-the-fly and shows a readable diff between 2 certificate files.

systemtap 3.0 release

Systemtap is a tool to simplify the gathering of information about the running Linux system. Lots of internal changes that could help the building of new tools _on top of _systemtap to visualise data.

gogs: Go Git Service

An easy to install git service, running as a single Go binary. Very impressive screenshots, it rivals Github/Bitbucket at first glance.

lwan web server

In development for over 4 years, Lwan was until recently a personal research effort that focused mostly on building a solid infrastructure for a lightweight and speedy web server. Low disk and memory footprints, simple architecture & small source code.


netdata is a new performance monitoring tool: a fast way to visualize metrics. It is a resource efficient, highly optimized system for collecting and visualizing any type of realtime timeseries data, from CPU usage, disk activity, SQL queries, API calls, web site visitors, etc. The demo dashboard looks impressive!

OpenBSD 5.9 released

Earlier than planned, OpenBSD 5.9 has been released to the world.


Caravel is a data exploration platform designed to be visual, intuitive, and interactive.


Abot makes it easy and fun to build your own digital assistant, and includes everything you need to get started. This open source tool allows you to create your own Jarvis (Iron Man) or Alexa (Amazon).


A tool for programmatically verifying database backups: Uphold will help you automatically test them by downloading the backup, decompressing, loading and then running programmatic tests against it that you define to make sure they really have what you need.

bcc: Dynamic Tracing Tools for Linux Fork on Github

This is a powerful tool that builds on BPF: an in-kernel virtual machine that can run tracing programs safely and efficiently (JIT & in-kernel aggregations).

Debian 8.4 released

Another release to the stable Debian 8 series: Debian 8.4 is out.

Guide & Tutorials

FlexSC: Flexible System Call Scheduling with Exception-Less System Calls (PDF)

This research paper proposes a new mechanism for applications to request services from the operating system kernel: exception-less system calls. The goal is to have less context-switching by the kernel to improve processor efficiency. Highly theoretical, but could one day make its way to the Linux kernel.

Good practices for writing shell scripts

A very practical guide for writing shell scripts: useful tips on shebang, argument values, function usage, variables, …

Let’s Encrypt & Nginx

A step-by-step guide on how to use Let’s Encrypt with Nginx for a secure, modern TLS configuration.

Using Puppet with CoreOS, rkt, Flannel and etcd

A practical guide on using CoreOS, rkt, Flannel and etcd together with Puppet’s config management. Lots of practical implementation details, too.

An introduction to distributed systems

It’s not exactly an “introduction” as much as a “total overview” though. Very detailed writeup on distributed systems fundamentals.

An introduction to Tmux

Tmux is a terminal multiplexer: it’s like a power-up for terminal programming. You can manage several terminals under a session, split terminal screens, detach and re-attach sessions and much more. This guide offers a very good introduction to using and mastering it.

Running Bash Commands in the Background the Right Way

A good article on sending Bash scripts to the background, with practical info on using “&”, disown, nohup, … There are a couple of ways to achieve the same goal, they’re further explained in this article.

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