Installing Python 3 on RHEL

Installing from RPM is generally better, because:

• you can install and uninstall (properly) python3.
• the installation time is way faster. If you work in a cloud environment with multiple VMs, compiling python3 on each VMs is not acceptable.

Solution 1: Red Hat & EPEL repositories

Red Hat has added through the EPEL repository:

• Python 3.4 for CentOS 6
• Python 3.6 for CentOS 7

[EPEL] How to install Python 3.4 on CentOS 6

sudo yum install -y epel-release
sudo yum install -y python34

# Install pip3
sudo yum install -y python34-setuptools  # install easy_install-3.4
sudo easy_install-3.4 pip

You can create your virtualenv using pyvenv:

pyvenv /tmp/foo

[EPEL] How to install Python 3.6 on CentOS 7

With CentOS7, pip3.6 is provided as a package :)

sudo yum install -y epel-release
sudo yum install -y python36 python36-pip

You can create your virtualenv using pyvenv:

python3.6 -m venv /tmp/foo

If you use the pyvenv script, you'll get a WARNING:

$ pyvenv-3.6 /tmp/foo
WARNING: the pyenv script is deprecated in favour of `python3.6 -m venv`

Solution 2: IUS Community repositories

The IUS Community provides some up-to-date packages for RHEL & CentOS. The guys behind are from Rackspace, so I think that they are quite trustworthy...

https://ius.io/

Check the right repo for you here:

https://ius.io/setup

[IUS] How to install Python 3.6 on CentOS 6

sudo yum install -y https://repo.ius.io/ius-release-el6.rpm
sudo yum install -y python36u python36u-pip

You can create your virtualenv using pyvenv:

python3.6 -m venv /tmp/foo

[IUS] How to install Python 3.6 on CentOS 7

sudo yum install -y https://repo.ius.io/ius-release-el7.rpm
sudo yum install -y python36u python36u-pip

You can create your virtualenv using pyvenv:

python3.6 -m venv /tmp/foo

It is easy to install python manually (i.e. build from source):

1. Download (there may be newer releases on Python.org):

    $ wget https://www.python.org/ftp/python/3.4.3/Python-3.4.3.tar.xz
   

2. Unzip

    $ tar xf Python-3.* 
    $ cd Python-3.*
   

3. Prepare compilation

    $ ./configure
   

4. Build

    $ make
   

5. Install

    $ make install
   

   OR if you don't want to overwrite the python executable (safer, at least on some distros yum needs python to be 2.x, such as for RHEL6) - you can install python3.* as a concurrent instance to the system default with an altinstall:

    $ make altinstall
   

Now if you want an alternative installation directory, you can pass --prefix to the configurecommand.

Example: for 'installing' Python in /opt/local, just add --prefix=/opt/local.

After the make install step: In order to use your new Python installation, it could be, that you still have to add the [prefix]/bin to the $PATH and [prefix]/lib to the $LD_LIBRARY_PATH (depending of the --prefix you passed)

In addition to gecco's answer I would change step 3 from:

./configure

to:

./configure --prefix=/opt/python3

Then after installation you could also:

# ln -s /opt/python3/bin/python3 /usr/bin/python3

It is to ensure that installation will not conflict with python installed with yum.

See explanation I have found on Internet:

http://www.hosting.com/support/linux/installing-python-3-on-centosredhat-5x-from-source

Along with Python 2.7 and 3.3, Red Hat Software Collections now includes Python 3.4 - all work on both RHEL 6 and 7.

RHSCL 2.0 docs are at https://access.redhat.com/documentation/en-US/Red_Hat_Software_Collections/

Plus lot of articles at developerblog.redhat.com.

<opinion> Using the SCL yum repos may be better than other yum repos because the RPMs are developed/tested by Redhat (i.e. first-party RPMs instead of third-party). </opinion>

edit

Follow these instructions to install Python 3.4 on RHEL 6/7 or CentOS 6/7:

# 1. Install the Software Collections tools:
yum install scl-utils

# 2. Download a package with repository for your system.
#  (See the Yum Repositories on external link. For RHEL/CentOS 6:)
wget https://www.softwarecollections.org/en/scls/rhscl/rh-python34/epel-6-x86_64/download/rhscl-rh-python34-epel-6-x86_64.noarch.rpm
#  or for RHEL/CentOS 7
wget https://www.softwarecollections.org/en/scls/rhscl/rh-python34/epel-7-x86_64/download/rhscl-rh-python34-epel-7-x86_64.noarch.rpm

# 3. Install the repo package (on RHEL you will need to enable optional channel first):
yum install rhscl-rh-python34-*.noarch.rpm

# 4. Install the collection:
yum install rh-python34

# 5. Start using software collections:
scl enable rh-python34 bash

UPDATE 2021-08-16:

• rhel and centos version 7 are now on python 3.6 by default i believe
• the SCL yum repo has python version 3.8 as of the date of this writing 2021-08-16 (despite the question still referencing the older python 3.4 version)

Use the SCL repos.

sudo sh -c 'wget -qO- http://people.redhat.com/bkabrda/scl_python33.repo >> /etc/yum.repos.d/scl.repo'
sudo yum install python33
scl enable python27

(This last command will have to be run each time you want to use python27 rather than the system default.)