nsenter is a great command line tool for accessing docker containers. Unfortunately it isn’t available in Ubuntu 14.04 at the time of writing. Fortunately building it from source is quite simple. Get the latest version of util-linux from kernel.org https://www.kernel.org/pub/linux/utils/util-linux/ At the time of writing the latest version was v2.25, which is the version used in the examples here. Install the build dependencies sudo apt-get install build-essential libncurses5-dev libslang2-dev gettext zlib1g-dev \ libselinux1-dev debhelper lsb-release pkg-config po-debconf autoconf \ automake autopoint libtool python2.

Like most Linux users, I appreciate the power and flexibility of open source and like that my development PC runs the same software as my servers. While building a desktop PC and installing Ubuntu on it is great n’ all, I wanted my next Linux desktop to be a little more portable. Coding in the garden anyone? yes please! Now, I really like the look of Apple’s macbook air. But apple’s wonder machine is out of my budget and I’d also have had to switch from Linux to MacOX.

Using an SSH tunnel is a great way to administer remote services without having to directly expose them to the internet. You basically forward a port from your local machine (e.g. your Linux desktop) to a port on the remote server. You can then connect to the port on localhost and the magic of ssh will forward the port securely to the remote machine. To the remote server you’ve connected locally on localhost!

If you do a fair amount of tinkering on cloud servers, such as EC2 or Digital Ocean, then you’ll have noticed that each time you start a server it gets a new IP address allocated. Then when you next log on to the server via ssh the server gets added to your known_hosts file.

Before long your known_host file has dozens, if not hundreds of entries for servers that you’ve long shut down and discarded.

At first I would edit the known host file and remove the server entry once I’d done with the server, but this got tiresome after a while.  So, I decided that for the servers I’m just messing about on I’d rather not add the server into the known_hosts file at all.

Using Bitbucket from a network that does not allow ssh (port 22) connections means that doing a git push or pull using the standard git ssh remote won’t work. git remote add origin https://[email protected]/USERNAME/REPOSITORY.git Where USERNAME is your user/login name and REPOSITORY is the name of the repository you want to access. If you don’t want to enter your password every time you connect to the remote you can include the password in the remote url: git remote add origin https://USERNAME:PASSWORD@bitbucket.

How to add a swap file (not partition) to linux

A quick’ cut and paste’ tip for setting the timezone on Centos / Red Hat Linux. To set it for the UK, as the root user, enter the following: ln -sf /usr/share/zoneinfo/Europe/London /etc/localtime All of the different timezones can be found in /usr/share/zoneinfo under various subdirectories, e.g. Europe, Africa etc. To set the appropriate timezone just replace the symbolic link at /etc/localtime to point the the relevant timezone file. In the example above the symbolic link, /etc/localtime is updated to point to the London timezone file.

I recently started using the excellent digital ocean for some of my cloud server hosting. When logging into my servers there was quite a delay, often a minute or more, before the password prompt appeared. I was getting the same delay when I use SSH keys for authentication too.

By far the most popular source control system in use today is Git. It was only about 6 months ago I made the switch from subversion for my personal code projects, and the only regret I have is that I didn’t do it earlier!

I’m lucky enough to experience code management at both ends of the spectrum. In my spare time I tinker with personal projects (some public but mostly private stuff). At work ‘enterprise’ would definitely be an appropriate description of our source code management.

With the advent of cloud computing, source control can no longer be kept neatly behind corporate firewalls.Of course you could stick a Subversion server or Git repository in your DMZ, but really, the correct answer is hosting.

There are many source-code hosting providers to choose from, but in this post I’m going to look at the two most popular Git hosting solutions: Github and Bitbucket.

Stud is the “Scalable TLS Unwrapping Daemon” written by bumptech and used by 85million bump users. I use it to offload SSL connections in front of haproxy for really scalable websites. It’s not so much that I need to scale massively, but it does allow me to run on really small (i.e. cheap) servers. I’m aware that the development branch of HAproxy now supports SSL directly, but as yet I have not seen any performance tests so for now I will stick with stud.

I have previously built stud on Debian Linux and the build process is really simple; make and then make install (once openssl-devel in installed and or course the utilities gcc and make too!)

But I’ve recently moved over to Centos as my server OS of choice and ran into some problems whilst building stud. The error reported when I ran make was file ev.h not found.