What is a ‘unikernel’?

Author: | 3 Comments
If you've been following the Devops Weekly newsletter, DevOps-like conferences or if you're just really interested in technology, you've probably heard of unikernels being mentioned a few times. In the last few months, its popularity has greatly increased.

Querying JSON data at the command line with ‘jq’

Author: | No comments
If you're not familiar with the tool yet, I'd like to introduce you to jq: a lightweight and flexible command-line JSON processor.

PHP’s Memcached sessions: Failed to write session data (memcached) for Magento

Author: | 2 Comments
A couple of days ago I was debugging a particularly interesting problem with PHP's sessions being stored in a Memcached instance. More specifically, this system was running the Magento eCommerce software.

Create a password-protected ZIP file on Mac OSX

Author: | 1 Comment
If you want to send someone a file of which the content you prefer to remain anonymous, you can send it in a password protected ZIP file.

Chrome drops NPN support for HTTP/2, ALPN only

Author: | 2 Comments
Update 23/11: Chrome reverted the change, NPN is allowed again! More details below. If this cryptic title doesn't mean much to you, let me rephrase it in more words: Chrome is switching to the newer Application-Layer Protocol Negotiation (ALPN) extension for TLS negotiation. ALPN requires at least OpenSSL 1.0.2.

Simulate low-bandwidth conditions with Chrome’s network throttling

Author: | No comments
Chrome has a built-in developer feature that allows you to simulate low-bandwidth conditions on website. This is very useful if you're testing mobile versions of an application (with GPRS/3G/4G/...) or want to test network congestions and high latency situations. And it's built-in to Chrome already! To get started, browse

Auto resize screen size for Windows 10 guest VMs in Virtualbox

Author: | No comments
If you're running Virtualbox on your system to virtualise Windows or Linux VMs, either manually or through Vagrant, you can have the VM auto resize its display when you resize the window on your host.

Nginx: Cannot assign requested address for upstream

Author: | No comments
A few days ago, I ran into the following interesting Nginx error message.

Linux increase ip_local_port_range TCP port range

Author: | No comments
For heavy traffic network servers, like proxy servers or load balancers, you may need to increase the networking port range.

Enable Keepalive connections in Nginx Upstream proxy configurations

Author: | No comments
A very common setup to see nowadays is to have an Nginx SSL proxy in front of a Varnish configuration, that handles all the SSL configurations while Varnish still maintains the caching abilities. It's one of my "2015 server stack predictions" that held up pretty accurately so far. Although,