Personally, I find it difficult to remember which SCLs (software collections) I have enabled while I am doing development. Or, perhaps more likely, when I get distracted from development and I come back to the window I was using before. As a result, I added the following to my bashrc which displays in the prompt what SCLs are enabled.
Continue reading Making SCL use a little saner
Have you wanted to use software collections but found packaging has kept you at bay? Tried rebuilding a package only to find it give you weird errors you’ve not seen before? In this blog post we’ll learn how to configure and use mock to build RPM packages for the Python 2.7 Software Collection. Along the way we’ll learn why we can’t use standard mock configurations, and what makes Software Collections (SCL) mock configurations different.
Continue reading “Using Mock to build Python27 Software Collections packages for RHEL6”
WebSockets are a rising technology that solves one of the great needs of web development – full duplex communication between a browser (or a different client) and a server.
Let’s imagine a simple scenario – live web chat. In the past, you’d probably use AJAX and polling to make new posts appear in realtime. The downside is that implementing all that is not entirely easy and it tends to put a lot of strain on the server.
This article will show you how to implement a simple web chat using WebSockets, thus eliminating the above problems. We will be using the Tornado web server with the Flask framework, producing a pure Python solution. To get the maximum out of Python 2.x, we will utilize the python27 Software Collection (SCL). We will also need a newer version of Firefox that supports WebSocket technology, so that we can test from the RHEL 6 machine that we’re developing on.
Continue reading “Unleashing Power of WebSockets on RHEL 6”
Did you ever wish you had newer versions of the software on your Red Hat Enterprise Linux machines? You are probably not alone. Providing new versions of software in rpm is hard, because rpm supports only one version installed on your computer at a time. Multiple versions on one machine can conflict with each other or create unpredictable behaviour in applications that you might not have considered dependencies.
Last year, we developed Software Collections to allow you to install newer versions of software in rpm safely into /opt and switch between new and old releases. This allows your Red Hat Enterprise Linux system applications to continue to run with the old version, while new apps can work with the new version. A good example of this is Python; many essential packages are written in Python. How can you update to the latest release of Python without causing half your system to break? Through Software Collections, you can install a newer version of Python – for example python-3.3 – into /opt avoiding conflicts in files and strange behaviour of apps that depend on an older version of Python.
I have multiple collections on my RHEL-6 machine for testing purposes. Let’s see all of them:
[root@rhel-6-marcela ~]# scl -l
How can you install those collections?
These collections are located as testing repositories on various “people pages.” You can add their repository into your /etc/yum.repos.d/:
Continue reading “Software Collections on Red Hat Enterprise Linux”