src/RpkUtils/Sysinfo/Server.php
public static function uptime()
    {
        $uptime = -1;
        if(false !== ($data = @file("/proc/uptime"))){
            $data   = explode(' ',reset($data));
            $uptime = reset($data);
        }
        
        return floatval($uptime);
    }
public static function uptime()
    {
        $uptime = -1;
        if(false !== ($data = @file("/proc/uptime"))){
            $data   = explode(' ',reset($data));
            $uptime = reset($data);
        }
        
        return floatval($uptime);
    }
Server uptime
@return float seconds