Question

I’m setting something up to SSH out to several servers in ‘batches’. I basically want to maintain 5 connections at a time, and when one finishes open up another (following an array of server IPs).

I’m wondering for something like this should I be using fork()? If so, what logic can I use to ensure that the I maintain 5 children at a time?

Answer 1

Forking (or threading) is what you want, but you should look at CPAN for modules that will provide most of what you need to prevent you from reinventing the wheel and going through the learning pains of what you need to do.

For example, Parallel::ForkManager looks like it’s EXACTLY what you want.

use Parallel::ForkManager;

$pm = new Parallel::ForkManager($MAX_PROCESSES);

foreach $data (@all_data) {
  # Forks and returns the pid for the child:
  my $pid = $pm->start and next; 

  ... do some work with $data in the child process ...

  $pm->finish; # Terminates the child process
}