Encountering No module named 'cdiff while running select gitlab-ctl patroni commands

Description

Commands like gitlab-ctl patroni restart, gitlab-ctl patroni reload, gitlab-ctl patroni members fail with error message:

ModuleNotFoundError: No module named 'cdiff'

Environment

  • Impacted offerings:

    • GitLab Self-Managed

  • Impacted versions:

    • 16.8 to 17.1

  • Impacted services:

    • Patroni

Solution

Upgrade to the latest patch release for your desired major and minor versions of GitLab. For example, if you encountered this problem when upgrading to 16.8.6, upgrade to the latest 16.8.x version of GitLab.

Workaround

Overwrite the version of ydiff with version 1.2 using the command:

curl -o /opt/gitlab/embedded/lib/python3.9/site-packages/ydiff.py https://raw.githubusercontent.com/ymattw/ydiff/1.2/ydiff.py

Cause

As a part of configuring Patroni during upgrades, we run pip install patroni. Affected versions of Gitlab use ydiff v1.3, a dependency of patroni. The version of patroniinstalled is not compatible withydiff>=1.3`. See Pin ydiff version to 1.2 for more information.

Additional information

This problem does not impact all gitlab-ctl patroni subcommands; things like gitlab-ctl patroni check-leader will continue to work properly.

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