Elastica\Client::_initConnections PHP Method

    protected function _initConnections()
    {
        $connections = [];
        foreach ($this->getConfig('connections') as $connection) {
            $connections[] = Connection::create($this->_prepareConnectionParams($connection));
        }
        if (isset($this->_config['servers'])) {
            foreach ($this->getConfig('servers') as $server) {
                $connections[] = Connection::create($this->_prepareConnectionParams($server));
            }
        }
        // If no connections set, create default connection
        if (empty($connections)) {
            $connections[] = Connection::create($this->_prepareConnectionParams($this->getConfig()));
        }
        if (!isset($this->_config['connectionStrategy'])) {
            if ($this->getConfig('roundRobin') === true) {
                $this->setConfigValue('connectionStrategy', 'RoundRobin');
            } else {
                $this->setConfigValue('connectionStrategy', 'Simple');
            }
        }
        $strategy = Connection\Strategy\StrategyFactory::create($this->getConfig('connectionStrategy'));
        $this->_connectionPool = new Connection\ConnectionPool($connections, $strategy, $this->_callback);
    }