Plesk Lin: Systemctl fails to start service: Too many levels of symbolic links

The issue appear when a Plesk Linux server is using centos 7.7 and under /var/log/messages you will see some lines like :

systemd-tmpfiles: Adjusting owner and mode for /sys/class/net/lo failed: Too many levels of symbolic links
systemd-tmpfiles: Adjusting owner and mode for /sys/class/net/venet0 failed: Too many levels of symbolic link

Usually daemon process that affected is spamassassin and fai2ban.

systemctl status spamassassin.service
● spamassassin.service - Spamassassin daemon
Loaded: loaded (/etc/systemd/system/spamassassin.service; enabled; vendor preset: disabled)
Active: activating (start) since Wed 2019-09-18 20:47:36 CEST; 16s ago
Process: 31790 ExecStart=/usr/bin/spamd --pidfile /var/run/spamd.pid $SPAMDOPTIONS

What causing this?

The recent CentOS 7.7 update includes an update to systemd-219-67, which changed how systemd opens symbolic links and causes incompatibility issues with old kernels.

How to Solve?

1. Connect to SSH
2. Modify which daemon having issue, for example : systemctl edit –full spamassassin.service
3. Set the PIDfile parameter from /var/run/<service-name>.pid to /run/<service-name>.pid
4. reload the daemon : systemctl daemon-reload
5. start the service : systemctl start spamassassin.service

Details on plesk : https://support.plesk.com/hc/en-us/articles/360035549754-Systemctl-fails-to-start-service-Too-many-levels-of-symbolic-links-