cron.weekly issue #107: Intel, man, PHP, sslh, ping, Docker, groups & more

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Mattias Geniar, November 26, 2017

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Welcome to cron.weekly issue #107 for Sunday, November 26th, 2017.

The weather in Belgium is turning into typical winter (rain, rain & rain), so I expect the next cron.weekly’s to have more content, as we all start writing blogposts, frustrated that we can’t get out of the house.

Or not – we’ll see. 🙂


Introducing container-diff, a tool for quickly comparing container images

I linked to Google’s container-diff a few issues ago, this post explains the reasoning behind the tool, their use cases & how it came to be. Nice to see this kind of openness from Google!

Reviving the 1973 Unix Programmer’s Manual

A fun read on how to recover a 40+ year old manual for Unix and the hacks this person had to go through in order to convert it to an actual PDF. As a bonus, that PDF is at the bottom of his post.

Intel CPU vulnerabilities

Nearly every Intel CPU from the last years has shipped with a “Management Engine” (aka: a tiny, critical OS) that contains a serious vulnerability. You might want to investigate if your environment needs patching.

Why does man print “gimme gimme gimme” at 00:30?

There’s always a bit of trivia to learn in Linux. 🙂

Why Linus is right (as usual)

This post is a response to one of Linus’ public rants against security people, where he argues that security issues are in fact “bugs” and should be treated as such, sometimes even sacrificing (a small bit of) security in the process.

Why we never thank open source maintainers

An homage to all the hidden things open source maintainers do, other than just writing code from their couch.

Anatomy of a PHP Hack

If you’ve worked on PHP servers long enough, chances are you’ve had to pleasure to see web applications get compromised and get random code inserted into the legit code. This post explains one such hack and decodes the hacked PHP code involved.

This site is a collection of guides & tutorials about a variety of topics, from Ansible to PHP development, Docker & Jenkins.

Tools & Projects

Get full-stack observability with Datadog

Go from a global view of your infrastructure to inspecting an individual request trace, all in one developer-friendly platform. Start a free 14-day trial. (Sponsored)

APPUiO: Open Container Platform with a Powerful Community

The Swiss Container Platform APPUiO is based on OpenShift by Red Hat. Reliable Open Source concepts such as Docker and Kubernetes allow you to develop, operate and scale your application according to your needs. Contact us for a free one month trial of APPUiO. (Sponsored)


An interactive console program that allows traffic flows to be intercepted, inspected, modified and replayed.


sslh acts as a protocol demultiplexer, or a switchboard. sslh accepts connections on specified ports, and forwards them further based on tests performed on the first data packet sent by the remote client.

Guides & Tutorials

Continuous Delivery for Mobile Development – GoCD

This post chronicles a mobile app development team’s journey to continuous delivery, the challenges along the way, how they overcame them and their thoughts beyond continuous delivery. Check it out. (Sponsored)

Scaling Postgres with Read Replicas & Using WAL to Counter Stale Reads

A solid introduction to how replication works in PostgreSQL, what replication lag is and an interesting approach to routing SQL queries to replicas that are current, instead of still reading their WAL files.

How do groups work on Linux?

Some very interesting bits about “groups” on linux. Did you know that a running process needs to be restarted, if you change it’s user’s group ID?

Backends High Availability at BlaBlaCar

Quite an interesting read on this compan’s move to Docker and how they treated their more difficult assets, 1TB MySQL servers.

Ping at the speed of light

So how fast do packets fly over the wire?


Texas Linux Fest 2018

This is both a reminder that Texas Linux Fest willen happen in June next year, and they’re looking for speakers. If you like speaking – or would like to try – fill in their Call For Presentations (CFP).

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