composer require tinywan/load-polling 

// 服务器数
$services = [
    '192.168.10.1' => 5,
    '192.168.10.2' => 1,
    '192.168.10.3' => 1,
];

// 使用平滑加权算法 (Smooth Weighted Round Robin)
$robin = new \Robin\SmoothWeightedRobin();
$robin->init($services);

$nodes = [];
$sumWeight = $robin->getSumWeight();
for ($i = 1; $i <= $sumWeight; $i++) {
    $node = $robin->next();
    $nodes[$i] = $node;
}
var_export($nodes);

// 会生成如下均匀序列
array (
  1 => '192.168.10.1',
  2 => '192.168.10.1',
  3 => '192.168.10.2',
  4 => '192.168.10.1',
  5 => '192.168.10.3',
  6 => '192.168.10.1',
  7 => '192.168.10.1',
)

"repositories": {
    "packagist": {
        "type": "composer",
        "url": "https://packagist.org"
    }
}