What does this mean?

 sudo /usr/local/centovacast/bin/ccmanage cronjob all --debug
[DBG] Attempting to set user context to all
Result: ERROR Another cron job instance is already running

That means that cron is already running... If you wait a few minutes or so, you can try running it again.

This is an error I get when I try and debug the system just before a batch of servers go down and restart.

"Check your cron log (usually /var/log/cron on Red Hat-based Linuxes, or /var/log/syslog on Debian-based Linuxes) and search for the words ccmanage cronjob. Find the most recent entry (near the bottom)."