debug.php

<?php

$host = "redis-vanilla-0";
$port = 26379;

var_dump("phpredis", phpversion('redis'));

try {
  $redis = new Redis([
    'host' => $host,
    'port' => $port,
    // 'auth' => 'secret',
  ]);
  $ping = $redis->ping();
  var_dump("client", $ping);
} catch (Throwable $th) {
  var_dump("client error", $th);
}

try {
  $sentinel = new RedisSentinel([
    'host' => $host,
    'port' => $port,
    // 'auth' => 'secret',
  ]);
  $ping = $sentinel->ping();
  var_dump("sentinel", $ping);
  $masters = $sentinel->masters();
  var_dump("masters", $masters);
} catch (Throwable $th) {
  var_dump("sentinel error", $th);
}