Forum Discussion
Kevin_106976
Nimbostratus
NimbostratusF5 and WebLogic
Can someone tell me what the difference is between the following two ?
*** Setup 1
F5 VIP -> Apache Web Servers (say two in a pool) -> WebLogic Servers (say 10)
The F5 VIP does not have any persistence profile setup
*** Setup 2
F5 VIP -> Apache Web Servers (say two in a pool) -> WebLogic Servers (say 10)
The F5 VIP is setup with a cookie level persistence
*** In both of the above, the Apache Web Servers talk directly to the WebLogic Servers ; in other words there is no f5 between them.
Now, I know that both of the above work but I cannot seem to understand the subtle difference between the two setups. And why I would choose one over the other ?
- Chris_Miller
Altostratus
In setup 2, the F5 is inserting a cookie on the client's browser that maps them to a specific pool member for as long as the cookie's expiration. In setup 1, the user will not be persistent to any machine.
You'd choose Setup 2 if you needed to send subsequent requests to the same apache server. If the servers behind the Apache boxes manage this persistence on their own via JSESSIONID for instance, you might not need the cookie. Here's a question - if your first request goes to Apache 1 and your second goes to Apache 2, what's the impact? How about if a user has logged in on apache 1 and they then get sent to apache 2? 
Kevin_106976Thanks Chris. (In step 2) when you say that the f5 is adding a cookie to persist to a particular pool member, which pool are you referring to - Apache or WebLogic ? I am assuming you mean Apache ; so this is what I did - I setup the pool with only one member. Now with the f5 cookie setup, the requests always go to the same WebLogic server. Without the f5 cookie setup, there is no real guarantee as to which WebLogic server the request will go to. And this is why I am confused - I dont see how f5 can maintain persistence all the way to the WebLogic servers - when the WebLogic servers are not even managed by f5 !
Regarding your question about what would happen if the request is sent to a different Apache instance - well the Apache instance will route it to the WebLogic cluster (which is just like a pool), the cluster will know which member is currently serving the session and will route the request to that member. So even this will work, but will make the cluster work a bit harder.- Chris_MillerPosted By Kevin on 07/25/2010 09:39 AM
Thanks Chris. (In step 2) when you say that the f5 is adding a cookie to persist to a particular pool member, which pool are you referring to - Apache or WebLogic ? I am assuming you mean Apache ; so this is what I did - I setup the pool with only one member. Now with the f5 cookie setup, the requests always go to the same WebLogic server. Without the f5 cookie setup, there is no real guarantee as to which WebLogic server the request will go to. And this is why I am confused - I dont see how f5 can maintain persistence all the way to the WebLogic servers - when the WebLogic servers are not even managed by f5 !
Regarding your question about what would happen if the request is sent to a different Apache instance - well the Apache instance will route it to the WebLogic cluster (which is just like a pool), the cluster will know which member is currently serving the session and will route the request to that member. So even this will work, but will make the cluster work a bit harder.
A pool member is the servers to which you're sending traffic. In this case, the apache boxes. So, by inserting cookies, the F5 keeps you going to the same apache boxes. If your apache boxes both send traffic to the same group of WL servers, you really don't need persistence. as WL persistence is handled by WL.
