Don't do that (parallel arrays). Either use an array of arrays (AoA):

my @IPMap = (
    [ "host_1", "192.168.1.1" ],
    [ "host_2", "192.168.1.2" ],
    [ "host_3", "192.168.1.3" ],
);
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or better, a hash:

my %IPMap = (
    host_1 => "192.168.1.1",
    host_2 => "192.168.1.2",
    host_3 => "192.168.1.3",
);
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YAML allows both structures to be generated directly from the configuration file. For example:

use strict;
use warnings;
use Data::Dump::Streamer;
use YAML ();

my $yamlStr = <<END_YAML;
---
host_1: "192.168.1.1"
host_2: "192.168.1.2"
host_3: "192.168.1.3"
---
-
    - host_1
    - "192.168.1.1"
-
    - host_2
    - "192.168.1.2"
-
    - host_3
    - "192.168.1.3"
END_YAML

my ($IPMapH, $IPMapAoA) = YAML::Load ($yamlStr);

Dump $IPMapH;
Dump $IPMapAoA;
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Prints:

$HASH1 = {
           host_1 => '192.168.1.1',
           host_2 => '192.168.1.2',
           host_3 => '192.168.1.3'
         };
$ARRAY1 = [
            [
              'host_1',
              '192.168.1.1'
            ],
            [
              'host_2',
              '192.168.1.2'
            ],
            [
              'host_3',
              '192.168.1.3'
            ]
          ];
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