Step-by-Step Guide to Installing Python 3 on CentOS 7 and Avoiding Common Pitfalls

Installing Python 3 on CentOS

This guide walks through the complete process of installing Python 3 from source on a CentOS machine, covering prerequisite libraries, source acquisition, compilation, environment configuration, verification, and common pitfalls.

1. Install prerequisite libraries

yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel

2. Download the Python 3 source code

You can obtain the source either from the official download page or directly via wget:

https://www.python.org/downloads/source/

wget https://www.python.org/ftp/python/3.6.1/Python-3.6.1.tgz

3. Create the installation directory

Choose a location for the custom Python installation, for example:

mkdir -p /usr/local/python3

4. Extract the source archive

tar -zxvf Python-3.6.1.tgz

5. Configure and compile the source

cd Python-3.6.1
./configure --prefix=/usr/local/python3
make
make install

6. Create a symbolic link for easy access

ln -s /usr/local/python3/bin/python3 /usr/bin/python3

7. Add the new binary directory to PATH

Edit ~/.bash_profile and append:

# Add custom Python3 to PATH
PATH=$PATH:$HOME/bin:/usr/local/python3/bin
export PATH

Save the file (Esc, :wq) and reload the profile.

8. Verify the installation

[user@host ~]$ python3 -V
Python 3.6.1
[user@host ~]$ pip3 -V
pip 9.0.1 from /usr/local/lib/python3.6/site-packages (python 3.6)

Common Pitfalls and Solutions

Pitfall 1: configure: error: no acceptable C compiler found in $PATH

Install the GCC compiler:

yum install -y gcc

Pitfall 2: zipimport.ZipImportError: can’t decompress data

Missing zlib development package; install it and recompile:

yum -y install zlib*

Pitfall 3: pip3: Can't connect to HTTPS URL because the SSL module is not available

Configure with SSL support:

cd Python-3.6.2
./configure --with-ssl
make
sudo make install

Pitfall 4: Multilib version conflicts

Identify duplicate library versions (e.g., openssl) and remove the unwanted one:

# rpm -qa | grep openssl
openssl-devel-1.0.0-27.el6_4.2.x86_64
openssl-1.0.0-27.el6_4.2.x86_64
openssl-1.0.0-27.el6_4.2.i686
# Remove the i686 package
rpm --erase --nodeps openssl-1.0.0-27.el6_4.2.i686
# Update remaining package
yum update "openssl*"

After resolving the conflict, re‑run the Python build steps.