[CentOS] respawning apache on centos

This is not CentOS, it's a compilation by your host built from changed 
CentOS sources. Your problem obviously is that you reach the limits of 
your VM. 1.5 GB of RAM should be enough for your 22 apache processes, so 
it is probably the CPU that is the bottleneck. Anyway, you have to talk to 
your provider, this is nothing CentOS-specific.

Kai