CentOs7: ssl module in Python is not available

Question

I am on CentOS Linux release 7.9.2009 (Core), installed python3.10.12 from source using the following script

sudo yum update

sudo yum groupinstall "Development Tools"
sudo yum install zlib-devel bzip2-devel \
  openssl-devel ncurses-devel sqlite-devel \
  readline-devel tk-devel gdbm-devel \
  libffi-devel xz-devel


wget https://www.python.org/ftp/python/3.10.12/Python-3.10.12.tgz


tar -xvf Python-3.10.12.tgz

./configure --enable-optimizations

make

sudo make altinstall


Python 3.10.12 (main, Jul  8 2023, 16:54:43) [GCC 4.8.5 20150623 (Red Hat 4.8.5-44)] on linux
Type "help", "copyright", "credits" or "license" for more information


sudo ln -s /usr/local/bin/python3.10 /usr/local/bin/python3

But, when trying pip, I got this error

There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/tutor/ (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.")) - skipping

Tried to list the ssl modules installed for python3, and got this

Also, when trying

python3.10 -m ssl

I got

ModuleNotFoundError: No module named '_ssl'

I found some answer that suggests adding --with-ssl option while building, and another answer that deosn't use this option at all. How can I solve this?

Answer 1

If you look at your ./configure output, you will see:

checking for --with-openssl-rpath...
checking whether OpenSSL provides required APIs... no
checking for --with-ssl-default-suites... python

So the configure script is failing to detect necessary support in OpenSSL. If we look at config.log, we find:

configure:17849: checking whether OpenSSL provides required APIs
configure:17895: gcc -pthread -o conftest  -std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Werror=implicit-function-declaration -fvisibility=hidden       conftest.c -lcrypt -lpthread -ldl  -lutil -lm -lssl -lcrypto   >&5
conftest.c:410:2: error: #error "OpenSSL >= 1.1.1 is required"
 #error "OpenSSL >= 1.1.1 is required"

And there's your problem; Python 3.10 requires OpenSSL version 1.1.1 or later, and CentOS 7 only provides 1.0.2.

If you want ssl support in your custom built Python, you'll need to first build a recent version of OpenSSL and install it somewhere on your system, and then provide configure with appropriate arguments to find it.

---

Alternately:

• If you need Python 3.10 on CentOS 7, consider running running it in a container.

• Consider installing a more recent operating system. CentOS 7 was originally released in 2014. That's almost 10 years ago. While it receives security updates, it doesn't receive feature updates, so it's simply not going to have recent versions of software.