for my $host (@hosts) {
    for (
        [ cmd1 => \@cmd1 ],
        [ cmd2 => \@cmd2 ],
    ) {
        my ($action, $cmd) = @$_;
        $pm->start("$action on $host") and next;
        exec(@$cmd, $host);
        print(STDERR "$action exec failed: $!\n");
        _exit($!); 
    }
}