Daily Maintanace scripts, Plesk update are stuck due to hanged /usr/libexec/urlgrabber-ext-down processes

Symptoms

• The following error message is shown in the Panel Interface:

  Unable to start Plesk Installer. The following error has occurred: Installation could not be started: another installation procedure is currently running

• It is not possible to synchronize subscription with service plan

• Starting Plesk update with Install Now at Tools & Settings > System Overview" leads to a new page with "Plesk Installer at the top without anything else shown below it.

• Executing Plesk update via CLI get stuck on the following message:

  Loaded plugins: fastestmirror

• The following processes are found with "ps" utility:

  # ps auxwwff
  (...)
  root 1488 0.0 0.0 113280 1236 ? Ss Feb15 0:00 _ /bin/bash /bin/run-parts /etc/cron.hourly
  root 1520 0.0 0.0 113412 1200 ? S Feb15 0:00 _ /bin/bash /etc/cron.hourly/asl
  root 1930 0.0 0.0 17204 4 ? S Feb15 0:00 | _ /var/asl/bin/aum -ck
  root 2127 0.0 0.0 113280 988 ? S Feb15 0:00 | _ sh -c /usr/bin/yum --enablerepo=tortix-common list updates aum ipset mod_security >/dev/null 2>&1
  root 2128 0.0 0.0 1465552 7880 ? S Feb15 0:01 | _ /usr/bin/python /usr/bin/yum --enablerepo=tortix-common list updates aum ipset mod_security
  root 2304 0.0 0.0 319456 5724 ? S Feb15 0:00 | _ /usr/bin/python /usr/libexec/urlgrabber-ext-down
  root 2312 0.0 0.0 319452 5300 ? S Feb15 0:00 | _ /usr/bin/python /usr/libexec/urlgrabber-ext-down
  root 1521 0.0 0.0 113640 792 ? S Feb15 0:00 _ awk -v progname=/etc/cron.hourly/asl progname { ???? print progname ":n" ???? progname=""; ??? } ??? { print; }
  (...)

• The yum processes are deadlocked or hang up indefinitely waiting for urlgrabber-ext-down process.

Cause

The issue is caused by a bug in RHEL/CentOS 7.9 operating system.

Resolution

Until a fix is provided by the OS Vendor, please use the following workaround as a momentary fix:

1. Connect to the server via SSH

2. Find hanged yum process and kill them:

   # ps auxwwff
   # kill -9 1520 1930 2127 2128 2304 2312 1521