Choosing the right Python interpreter

[markuslf]

On RHEL 8, if you install python3, you get Python 3.6. psutil for Python 3.6 is v5.4, which is too old - the disk-io-check will not work.

Alternatively, you can

• install python3.8 together with python38-psutil (v5.6),
• and/or python39 together with python39-psutil (v5.8) afterwards,

which both work for the disk-io check. If you use alternatives --config python, you can set your default version for the command python.

The problem: In our Python3 checks, we use the #!/usr/bin/env python3 shebang, which is (on RHEL) currently Python 3.6 - no matter what you set alternatives --config python to (in the following example set to 3.9):

$ python -V
Python 3.9.7

$ python3 -V
Python 3.6.8
$ python3.6 -V
Python 3.6.8
$ python3.8 -V
Python 3.8.12
$ python3.9 -V
Python 3.9.7

If you just install python38 or python39 right from the start and not python3, everything is fine.

How to handle this, if we want to enforce the use of Python 3.8+?

[markuslf]

Ok, it's too early in the morning. Simply let python3 point to python3.8 or python3.9 by using alternatives --config python3 (the "3" at the end makes the difference, of course).