I run two containers of an app behind an Haproxy and use sticky sessions. I configured it with a cookie as follow :
cookie SERVER insert indirect nocache
server app1 app-1:443 check ssl verify none cookie srv1
server app2 app-2:443 check ssl verify none cookie srv2
The cookie is attached to the requests of the frontend but when I check in the browser console in the network panel, most of the time, the SERVER cookie is set to "srv1" but sometimes it changes for "srv2". I detected it in the haproxy access logs.
Is it a normal behavior ? How to prevent ?
