tcp-check with persistent session cookie ? (2 replies)

Hi,

We encountered a big problem this afternoon, which crashed for a while one
of our websites, a java (tomcat+lift) application. We are using Haproxy 1.5.

For our backend, we're doing something like this, using tcp-check because
we need to check status AND a string, which is not possible with http-check
:

backend backend-mywebsite
balance roundrobin
option redispatch
option tcp-check
tcp-check send GET\ /check \ HTTP/1.1\r\nHost:\
www.mywebsite.fr\r\nConnection:\
close\r\n
tcp-check send \r\n
tcp-check expect string HTTP/1.1\ 200\ OK
tcp-check expect rstring "healthStatus":"(Healthy|DegradedMode)"
cookie JSESSIONID prefix nocache


server s1 s1:11503 weight 1 check inter 10s fall 3 rise 2 ssl cookie s1
server s2 s2:11503 weight 1 check inter 10s fall 3 rise 2 ssl cookie s2
server s3 s3:11503 weight 1 check inter 10s fall 3 rise 2 ssl cookie s3
server s4 s4:11503 weight 1 check inter 10s fall 3 rise 2 ssl cookie s4

For some reasons, the /check page didn't returned the correct application
status and our / returned a 500 even if /check was OK, so we decided to
check /.

After 20 minutes, our application crashed. In fact, our 4 fronts crashed at
the same time, and if we restarted them, 20 minutes after, they crashed
again. We lost some time because we were really thinking on a software bug,
before we realize the root cause.

* Each tcp-check send opens a session on the application
* Each session, on the / page, consumes 500 KB
* session duration : 30 minutes
* We have 4 Haproxy, doing 2 checks (the app provides 2 websites, so one
check for each Host: ), 6 times per minute = 48 checks, each minute. On
each front.
* After 20 minutes : more than 450 MB used in the app for sessions
* Full GC, crash

So, my question is :

Is it possible to get and store the JSESSIONID cookie returned by the
tcp-check expect (or something like this), and send it with the tcp-check
send, to reuse the same session ?

Is there a way for a health check to use persistent cookie session (always
the same, one per server), returned by the check ?

Thank you very much,

Sebastien Rohaut