- The `init` process (or systemd) sits at 100% CPU for lengthy periods of time
- You discover that pleskrc takes a very long time to run, even just a simple command like /usr/local/psa/admin/sbin/pleskrc httpd status will take a good 7-10 seconds rather than be instant.
- Logging in via SSH can take a good 30 seconds or longer
This is an indirect result of pleskrc's call to `/bin/systemctl list-unit-files` on line 304. Apparently this is a systemd bug described here (actually a bug in dbus) wherein there's a leak of scope units causing list-unit-files to take a very long time to compile and display its list. The workaround is to run the following command to clean up the scope unit sessions:
systemctl | grep abandoned | grep -e "-[[:digit:]]" | sed "s/\.scope.*/.scope/" | xargs systemctl stop
The bug on the systemd github page is marked closed because it's being presented by systemd, but the real issue appears to be with dbus. That was fixed in April 2017 with dbus version 1.11.10, however CentOS 7.5 uses 1.10.24 and presumably has not (or maybe can't) cherry picked this fix into their 1.10.24 distribution.
RHEL/CentOS Backport Bug Report/Tracking here.
Plesk Bug Tracker Report