Ubuntu16 installs python3.10 and encounters the problem that the version of openssl is too low and the solution

When compiling python3.10 from source code, I encountered a warning about the ssl module, but I ignored it and didn't care

As a result, when using pip to install third-party packages, the network cannot be connected:

 WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")

Want to import ssl package also failed

python3.10 openssl minimum required version of ---050aabfc99dd973ae44305eef2fe308c--- is 1.1.1

ubuntu16 comes with 1.0.x

I originally wanted to install a new version of openssl via sudo apt install libssl-dev openssl

But I found that it couldn't work. Finally, I downloaded and compiled an openssl to replace it.

Python versions 3.6 to 3.9 are currently compatible with OpenSSL 1.0.2, 1.1.0 and 1.1.1. In most cases, Python also works with LibreSSL >= 2.7.1, but there are some missing features and broken tests.
Specific reference: PEP 644 – Require OpenSSL 1.1.1 or newer