F5 LTM Virtual Edition : HTTP cookie persistence

[ Software info ]

I downloaded an evaluation version.

# bigpipe version | egrep -i version BIG-IP Version 10.1.0 3341.1084 ~ # vmware -v VMware ESXi 4.1.0 build-348481

[ Network Topology ]

 external LAN               internal LAN

VM1 --vSwitch----- LTM VE ------ vSwitch ----- VM2

                                      ----- VM3

external LAN : 10.0.0.0/24

internal LAN : 20.0.0./24

All virtual machines are Scientific Linux 6.1.

Virtual Server : 10.0.0.100

VM1 (client) : 10.0.0.1

VM2 (server) : 20.0.0.1

VM3 (server) : 20.0.0.2

[ port association of ESX’s vmx file and LTM’s port ]

vmx ethernet0 = LTM’s Mgt port

vmx ethernet1 = LTM’s 1.1 port

vmx ethernet2 = LTM’s 1.2 port

[ sample configuration ]

Virtual Server : 10.0.0.100

load balance method : round robin

persistence : cookie insert by LTM

create nodes ( vm2 , vm3 ) 

create a pool (http-pool) and add nodes ( vm2 , vm3 ) into that pool.

create virtual server

select a pool you created(http-pool) and select “cookie” for persistence.

[ access to Virtual Server from client (vm1) ]

LTM load balanced HTTP traffic to VM2 ( 20.0.0.1 )

cookie persistence is provided by LTM.

captured on client.

Set-Cookie : xxx means that LTM inserts a cookie when sending a first server’s reply to a client.
Cookie : xxx means that a client send a cookie LTM issued.
This method is to stick a client to the same server.

client  --------------------------- LTM ------------------------- server

     1. syn ->

     2. <- syn ack

     3. ack ->

     4. get with no cookie->

                                                            5. syn -> ( vm2 : 20.0.0.1)

                             6. <- syn ack

                                                            7. ack ->

                                                            8. <- response with no cookie

   9. <- response with cookie  

   10. get with cookie ->

                                                           11. get with cookie ( vm2 : 20.0.0.1 )