Yum on EC2 Linux Causes ModuleNotFoundError: No module named ‘dnf’ [Fixed]

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I just used Yum to install Git on my Linux AWS EC2 instance using the following commands: 👼

# Perform update on your instance:
sudo yum update -y
 
# Install git in your EC2 instance
sudo yum install git -y
 
# Check git version
git version

Error

But when running these commands in my shell, I got the error messages ModuleNotFoundError: No module named 'dnf': 😡

[ec2-user@ip-172-31-19-40 ~]$ sudo yum update -y
Traceback (most recent call last):
  File "/usr/bin/yum", line 61, in <module>
    from dnf.cli import main
ModuleNotFoundError: No module named 'dnf'

[ec2-user@ip-172-31-19-40 ~]$ sudo yum install git -y
Traceback (most recent call last):
  File "/usr/bin/yum", line 61, in <module>
    from dnf.cli import main
ModuleNotFoundError: No module named 'dnf'

The web didn’t provide good answers, so I thought I share my resolution in this short tutorial:

The problem was that I had just set the command python3 to my new Python installation 3.11, as explained in this tutorial:

⚡ Tutorial: How to Use Python 3.X (3.9, 3.10, or 3.11) as Default for “python3” in Linux?

Solution

Per default, python3 pointed to Python installation 3.9. While I did install Python 3.11 freshly on my Linux, I obviously had not installed the module 'dnf' for the new Python version. But as yum now used (uninitialized) Python 3.11 instead of (correctly initialized) Python 3.9, it raises the ModuleNotFoundError: No module named 'dnf'.

To fix this, you can simply set Python to the previous (correctly initialized) version 3.9 by running the following command:

sudo update-alternatives --config python3

In my case, I needed to select 1 to reset the command python3 to the old and correctly initialized Python version 3.9.

Now if I use Yum, everything works properly as set up by Amazon per default:

Of course, you can always reset Python3 to the new version again by running the same command again and choosing the other version:

sudo update-alternatives --config python3

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