Solve 'yum: command not found' in AWS Lambda Python 3.12 base image

📌 The Issue

When I tried to install the Microsoft ODBC Driver (msodbcsql17) inside my custom image using the AWS Lambda Python 3.12 base image:

FROM public.ecr.aws/lambda/python:3.12

I used this command:

RUN yum install -y msodbcsql17

But it failed with this error:

/bin/sh: yum: command not found

❓ Why It Happens

Starting with Python 3.12, the Lambda base image now uses Amazon Linux 2023.
This version does not have yum anymore. It now uses microdnf, a lighter and faster package manager.

🔗 Official AWS Reference:

Starting with Python 3.12, the AWS base image uses Amazon Linux 2023 instead of Amazon Linux 2.
AWS Blog: AWS Lambda Adds Support for Python 3.12

🛠️ Solution: Use microdnf Instead of yum

To fix this, I replaced all yum commands with microdnf in my Dockerfile.

Here is the working Dockerfile for installing msodbcsql17:

FROM public.ecr.aws/lambda/python:3.12

# Set working directory
WORKDIR /opt/python/

# Install dependencies using microdnf
RUN microdnf update -y && \
    microdnf install -y \
        gcc gcc-c++ make unixODBC-devel unzip python3-devel wget && \
    wget -qO- https://packages.microsoft.com/keys/microsoft.asc | tee /etc/pki/rpm-gpg/MICROSOFT-GPG-KEY && \
    echo -e "[packages-microsoft-com-prod]\nname=packages-microsoft-com-prod\nbaseurl=https://packages.microsoft.com/rhel/7/prod\nenabled=1\ngpgcheck=1\ngpgkey=file:///etc/pki/rpm-gpg/MICROSOFT-GPG-KEY" > /etc/yum.repos.d/msprod.repo && \
    ACCEPT_EULA=Y microdnf install -y msodbcsql17 && \
    microdnf clean all && \
    rm -rf /var/cache/yum /var/tmp/* /tmp/*

Key Points

microdnf is the new package manager in Amazon Linux 2023.
It works like yum for basic package installation.
This lets us install the msodbcsql17 driver needed to connect to Microsoft SQL Server from Lambda.

Final Result

After switching to microdnf, the image built successfully, and I was able to use pyodbc to connect to MS SQL Server inside Lambda using Python 3.12.

Extra Tip

If you’re packaging this as a Lambda Layer, copy only the needed .so files and drivers from /usr/lib64 and /opt/python to keep the layer size small.

🙌 Conclusion

If you’re using public.ecr.aws/lambda/python:3.12 and installing ODBC drivers or other system packages, make sure to use microdnf instead of yum.

📚 Further Learning

If you want to explore more, here are some valuable reads:

Connecting AWS Lambda to Microsoft SQL Server Using PyODBC by Linuxbeast
How to Build and Deploy Python Libraries for AWS Lambda Layers by Linuxbeast
How to Install and manage Python Versions on WSL Ubuntu by Linuxbeast

Solve ‘yum: command not found’ in AWS Lambda Python 3.12 base image