Running multiple Python versions on CentOS6/RHEL6/SL6

The default RHEL6.x installation comes with python 2.6.6 but some people (mostly developers) need newer versions of python (either 2.7.3 or 3.3). Upgrading the existing python packages is not recommended as it would likely cause issues with the OS, so the only way is to install the other version(s) alongside with the existing one. While some have the knowledge to compile or build the new packages themselves, others would prefer to go the easier way and use a package repository to install software on their machines.

Since the official repos only provide python 2.6.6 they’d need a 3rd-party repository to get newer python packages and luckily there is one called PUIAS (created and maintained by members of Princeton University and the Institute for Advanced Study) and it’s fully compatible with RHEL6 / CentOS6.

 

Install PUIAS repository

What you need for python packages is puias-computational repository which contains scientific and research packages. According to their instructions page they provide an rpm package to automatically install and configure the repo, but as of today the link is broken so you’d have to do it manually.

Here’s how:

 

• download and import the rpm gpg key

cd /etc/pki/rpm-gpg/
wget -q http://springdale.math.ias.edu/data/puias/6/x86_64/os/RPM-GPG-KEY-puias
rpm --import RPM-GPG-KEY-puias

As an optional step to confirm the rpm key has been imported successfully:

gpg --quiet --with-fingerprint /etc/pki/rpm-gpg/RPM-GPG-KEY-puias

 

• create the repository file as /etc/yum.repos.d/puias-computational.repo

cat /etc/yum.repos.d/puias-computational.repo
[PUIAS_6_computational]
name=PUIAS computational Base $releasever - $basearch
mirrorlist=http://puias.math.ias.edu/data/puias/computational/$releasever/$basearch/mirrorlist
#baseurl=http://puias.math.ias.edu/data/puias/computational/$releasever/$basearch
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-puias

 

• confirm the repo is functional (optional)

yum repolist | grep -i puias
* PUIAS_6_computational: puias.math.ias.edu
PUIAS_6_computational   PUIAS computational Base 6 - x86_64               1,455

You can now search for python 2.7.3 and / or 3.3 packages to see what rpms are available for download.

yum search python27
yum search python3

I chose to install both versions and their IDLE environment:

yum install python27 python3 python27-tools python3-tools

The result is really satisfying, I can now run python-2.6.6, python-2.7.3 and python-3.3 on the same machine at the same time on my CentOS 6.4 installation.

Hope this helps. Cheers!