I remoted into Joe’s system and looked about for a bit.
What I found was there was/is 3 versions of php and php-fpm installed and all were trying to run at the same time.
I stopped, php-fpm v5, php-fpm v7.0, and left php-fpm 7.2 running.
I could not find a handy copy of the official fog configuration for the www.conf file so I hand edited the distro’s version setting max processes to 50, start, min to 5 and spares to 6. I also set php max memory size to 256M.
After that I asked Joe to multicast deploy an image. He reported that he deployed to 24 systems. I watched the process status screen and the number of active php-fpm processes never went above 6 workers (where 50 is the max). Joe stated that all 24 machines deployed to completion.
So at this point I’m pretty sure the issue with this system was having multiple versions of php installed as the root cause. I’m not ready to rule out a www.conf file setting that is not right, but I’m happy with what I saw from the performance of php-fpm service in this multicast deployment.