cron.weekly issue #6: Kernel Releases, TLS, Hostess, Polscan, Dtrace, Docker & many more

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Mattias Geniar, December 12, 2015

Follow me on Twitter as @mattiasgeniar

This is the _cron.weekly _release for Sunday December 13th.


Mozilla stops shipping Firefox OS smartphones, goes IoT

A lot of media got this announcement wrong: Mozilla isn’t dropping Firefox OS, their OS optimised for smartphones. It is however stopping their work to build and ship smartphones through carrier partners. Instead, they’ll be focusing on Internet of Things (IoT) with the Firefox OS project.

Understanding the kernel release cycle

An interesting read to better understand how Fedora releases their new kernels and which versions are considered and which aren’t.

UEFI updates from within Linux

A nice announcement for us still managing physical hosts: firmware updates to UEFI in Linux will work out-of-the-box on Dell boxes in the near future.

TLS in the kernel

This discussion focusses on whether or not TLS, the Transport Layer Security used in HTTPs and all other encrypted protocols, should be part of the Linux kernel or remain a standalone project like OpenSSL.

Stop using gzip

A call for attention for a better compression algoritm called “xz”. It can compress up to twice as good as gzip and has been supported in most linux distributions since 2009.

Tools & Projects

prestashop-cli: manage prestashop from your shell

Similar to how drush works for Drupal or wp-cli for WordPress, prestashop-cli gives you a command line interface to interact with a prestashop install. This is ideal for us sysadmin folks who may not have a login to the web interface but who still want to have some control over the installation.

hostess: cli utility for managing /etc/hosts

Granted, it’s not exactly hard to manage your /etc/hosts file, but having a simple CLI interface to be used in scripts is an upside. Hostess is an idempotent command-line utility for managing your /etc/hosts file.

Nchan: pub/sub module for Nginx

This new project is a publish/subscribe (or “pub/sub” in short) module for Nginx. It can be configured as a standalone server, or as a shim between your application and tens, thousands, or millions of live subscribers.


Shellcheck automatically detects problems in sh/bash scripts and commands. Copy/paste your script and get an analysis back of _potential _security problems and bugs you may encounter in your script.

Polscan: Visualizing Configuration Drift

In a cluster of servers, all hosts should be identical – right? More than often you’ll find some hosts’ configuration drifts from others. Polscan helps mark those hosts and maps them out in a grid for easier identification.

Bashhub: Bash history in the Cloud

I wouldn’t recommend using it, but it’s a nifty proof-of-concept. Bashhub is a “Bash History in the cloud”. Interesting from a technology point of view, but I’ll never install this on any of my machines.

Guides & Tutorials

The architecture of Nginx

A very in-depth piece of writing on all the pieces where Nginx differs from more traditionals webservers like Apache. It details the workers, process handling, threads, …

A practical debugging session with ‘dtrace’

Given a real use case (“why are my tests running slow”), this blogpost shows you how to use the dtrace tool to find bottlenecks in an application by finding the system calls that cause the most time and CPU consumption.

Building for HTTP/2

Now that HTTP/2 is reaching a broader audience, it’s time to start thinking about how to make full use of it. This blogpost shares insights in the do’s and don’ts when trying to get the most out of HTTP/2.

systemd: Template unit files

Tools like systemd give us more abilities to script startup/stop of services and all the management that comes with of it. This guide shows you how the unit files work and how you can make unit files for your own custom services (like init.d scripts in SysVinit).

Scaling to 100M: MySQL is a Better NoSQL

This post will explain why this particular company found that using MySQL for the key/value use case is better than most of the dedicated NoSQL engines, and provide guidelines to follow when using MySQL in this way.

Docker Machine, Swarm and Compose for multi-container and multi-host applications

A practical guide on running docker containers using Docker Machine (an abstraction layer on top of Docker), Swarm (native docker clustering) and Compose (managing the applications inside Docker).

Defending Against Apache Web Server DDoS Attacks

This post features protection mechanisms to defend against Web server DDoS attacks against an Apache webserver.

Introduction to Nomad: Docker resource scheduler

There are many container schedulers nowadays: Fleet, Kubernetes, Mesos, Rancher, Swarm, … This post focusses on Nomad as a new container resource scheduler for Docker.

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