Nginx – Sticky sessions based on a cookie using nginx

apache-2.2nginxtomcat

Currently, we are using apache2 as frontend, and tomcat as backend. We are using mod_proxy_balancer and AJP. Also we are using stickysession by JSESSIONID cookie:

<Proxy balancer://backend>
     BalancerMember ajp://127.0.0.1:8008 min=10 max=100 ping=5 connectiontimeout=40 ttl=60   retry=20 route=node-1
     BalancerMember ajp://127.0.0.1:8009 min=10 max=100 ping=5 connectiontimeout=40 ttl=60 retry=20 route=node-2
     ProxySet lbmethod=byrequests timeout=30
     ProxySet stickysession=JSESSIONID|jsessionid nofailover=Off
</Proxy>

and using jvmRoute parameter in web.xml to add tail to JSESSIONID cookie:

<Engine name="Catalina" defaultHost="localhost" jvmRoute="node-1">

We are looking to switch to using nginx for our frontend. So far I haven't found any way to perform the same session affinity operation with nginx. Is there any solution for this? We are not using session replication, so getting sequential requests to the same backend is crucial.

Best Answer

Google suggests that there is an out-of-tree module for nginx that does this. I've never used it, since I consider sticky sessions to be the work of satan, but it'll be the first option I'd use if I had to implement it.

Correct way in new versions of nginx

Turn out my first answer to this question was correct at certain time, but it turned into another pitfall - to stay up to date please check Taxing rewrite pitfalls

I have been corrected by many SE users, so the credit goes to them, but more importantly, here is the correct code:

server {
       listen         80;
       server_name    my.domain.com;
       return         301 https://$server_name$request_uri;
}

server {
       listen         443 ssl;
       server_name    my.domain.com;
       # add Strict-Transport-Security to prevent man in the middle attacks
       add_header Strict-Transport-Security "max-age=31536000" always; 

       [....]
}

Nginx – Controlling Nginx proxy target using a cookie

Similar to this answer. Nginx's idiomatic approach to this kind of problems is via map.

Basically, you define a map in http section

map $cookie_proxy_override $my_upstream {
  default default-server-or-upstream;
  ~^(?P<name>[\w-]+) $name;
}

Then you simply use $my_upstream in location section(s):

location /original-request {
  proxy_pass http://$my_upstream$uri;
}

Nginx evaluates map variables lazily, only once (per request) and when you are using them.

Best Answer

Related Solutions

NGINX Redirect – How to Rewrite All HTTP Requests to HTTPS While Maintaining Sub-Domain

Correct way in new versions of nginx

Nginx – Controlling Nginx proxy target using a cookie

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