LFD is stopped and does not start automatically after cPanel version upgrades

Symptoms

LFD is stopped shortly after cPanel version upgrades and the following is logged to /var/log/lfd.log:

Apr  9 21:42:50 server lfd[7568]: cPanel upgrade detected, restarting ConfigServer services...
Apr  9 21:42:50 server lfd[7568]: cPanel upgrade detected, restarting lfd
Apr  9 21:42:55 server lfd[5573]: daemon restart requested
Apr  9 21:42:55 server lfd[5573]: Main Process: Can't use an undefined value as a symbol reference at /usr/sbin/lfd line 3150, <$pidfile_fh> line 62.

Apr  9 21:42:55 server lfd[5573]: daemon stopped

Description

This is occurring shortly after cPanel updates when the cPanel version is upgraded.

We've opened an internal case for our development team to investigate this further. For reference, the case number is CPANEL-52606. Follow this article to receive an email notification when a solution is published in the product. 

Workaround

Start LFD manually by running the following command in SSH or "WHM / Terminal" as root:

csf --lfd start

Optionally, if monitoring is enabled for LFD in "WHM / Service Manager", wait for the chkservd service to automatically restart the service.

Additional Resources

cPanel Docs - Service Manager