Plesk upgrade on CentOS/RHEL fails: Packages excluded due to repository priority protections

Symptoms

Plesk upgrade on CentOS/RHEL fails with the following message:

XX packages excluded due to repository priority protections

Cause

Some packages are held by more than one repository. The priorities plugin chooses packages from the highest-priority repository, excluding duplicate entries from other repos.

Resolution

1. Connect to the server via SSH.

2. Disable priorities plugin by editing /etc/yum/pluginconf.d/priorities.conf file the following way:

   # cat /etc/yum/pluginconf.d/priorities.conf
   [main]
   enabled = 0

3. Comment out the priority line in the /etc/yum.repos.d/CentOS-Base.repo repository file by adding the leading # symbol:

   [BaseOS]
    name=CentOS-8 - Base
    ...
    gpgkey=file:/etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial
    #priority=1

4. Launch the upgrade again.