Hi Nicky,

Thanks for your response, I read the document at 
https://symfony.com/doc/current/session/database.html
But because I am not familiar with symfony, so I don't understand the structure and the method when developing and configuring in Symfony.
Therefore, the content of the document is quite difficult to me to make sure how to start. 
Should I use only PHP to complete the configuration or I have to configure in three kind of document including YAML, XML and PHP?
If I use only PHP, what should I do? Just follow the guide on TAB PHP is enough?

Regards,
Trần Bình Dương (Mr)
IT Lecturer
Software Engineering Department , FPT University
29th Kilometer Thang Long Boulevard, Thach Hoa commune, Thach That Province, Education and Training Area, Hoa Lac High Tech Park, Ha Noi
Mobile:(+84) 936168165
Skype: avn_duong.tb
E-mail: duongtb@fe.edu.vn
Website: ....

Từ: Nicky Gerritsen <nickygerritsen@me.com>
Đã gửi: 31 Tháng Mười 2020 5:52 CH
Đến: domjudge-devel@domjudge.org <domjudge-devel@domjudge.org>; Tran Binh Duong (FE FPTU HN) <DuongTB@fe.edu.vn>
Chủ đề: Re: About: strange phenomenon on domjudge with system which has a hardware load balancer configuration.
 
You need to share sessions between the web servers. See https://github.com/DOMjudge/domjudge/wiki/Scaling-and-load-testing

Nicky
On 31 Oct 2020, 11:50 +0100, Tran Binh Duong (FE FPTU HN) <DuongTB@fe.edu.vn>, wrote:
Hi all,

Our contestants feedback about the error as follow:
“Invalid CSRF token”, moreover contestants were frequently experienced with kicking out phenomenon and very hard to log back into the system.

Our configuration is briefly depicted as follow:
                
                                                     / domserver 1 \
Client ——> HW load balancer <                         >== Mysql DB
                                                     \ domserver 2 /

Please give me some advice to solve the issue.

Trần Bình Dương (Mr)
IT Lecturer
Software Engineering Department , FPT University
29th Kilometer Thang Long Boulevard, Thach Hoa commune, Thach That Province, Education and Training Area, Hoa Lac High Tech Park, Ha Noi
Mobile:(+84) 936168165
Skype: avn_duong.tb
E-mail: duongtb@fe.edu.vn
Website: ....

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