Forum Discussion
dominicgunn_378
Nimbostratus
NimbostratusVS Pool Switch with iRules and DataGroups - Clarification
Hi guys,
I have a quick question about a routing setup described below. I'm essentially wondering what would happen to active connections/sessions should a pool flip happen. We have 2 pools, each with an equal number of members in
- Traffic routes to F5 VS through a CDN.
- Once traffic hits the F5 VS, an iRule plays that route pools based on a value specified in a data-group "active-pool".
- Active pool round-robins to the members.
During a software release, a script will update the value of "active-pool" (from pool-a to pool-b for example) and so the iRule will start routing connections to the "active" pool.
My question is in regards to sessions that were previously hitting the old pool, what would happen to them?
- Would the traffic start routing their requests to the new pool?
- Would the traffic continue routing traffic to the old pool?
- Would the traffic be dropped?
- Would the traffic receive some error message (e.x. 503, as the old pool members are not available?)
Cheers
- Kevin_Stewart
Employee
It depends on persistence and connection state.
- Any active TCP connections will, by default, continue to load balance to the same member.
- If some form of persistence is involved (ex. cookie), requests will continue to load balance to the defined member in the persistence table.
These connections will bleed away after some time, and all new sessions will load balance to the new pool.
