if there are not enough pool members in a pool send the traffic to another pool

[crawworth]

Hi everybody, how are you?.

I want to ask a question, I was looking in the forum but I can't find anything that accomplishes with I need it.

I have 10 nodes in a pool, 5 of them have a priority of 5 and the others have a priority of 10.

Our customer wants when there are only three pool members of high priority available, the F5 send all the traffic to the lower priority nodes, the problem here is, when that happens, F5 send the traffic to the lower priority (that is ok) but he uses the nodes with high priority available in the balancing too, is there any way to stop that?.

Regards,

Oscar.

[Jim_Schwartzme1]

This could be performed via an iRule and having 2 pools. Pool A will high the 5 higher priority members and Pool B will have the 5 lower priority members.

when CLIENT_ACCEPTED {
     if { [active_members [LB::server pool]] < 4 }{
          Pool B
     }
     Else {
          Pool A
     }
}

[crawworth]

Thanks i'm gonna to check that too.

[Daniel_Wolf]

Hi @crawworth,

you could achieve the same with priority group activiation. See Manual Chapter : About Pools 
Here is an example. The pool members with the higher priority (5) will be used first. If less than four are available, the second priority group members will be used too.

KR
Daniel

[Jim_Schwartzme1]

Except doesn't want to use the higher priority servers when there are 3 or less. 

F5 send the traffic to the lower priority (that is ok) but he uses the nodes with high priority available in the balancing too, is there any way to stop that?.

[Daniel_Wolf]

Oh... I had to read that a couple of times more to understand that 🙂

In that case you could create individual monitors for each pool member. Assign each poolmember of prio group 1 five individual monitors (for itself and the four other prio 1 server) and have an up requirement of 4.
If only 3 poolmembers of prio 1 are online, this will mark all 5 as down.
Makes sense? Or a picture will explain more than 1000 words?

However, the above described solution doesn't scale. The iRule solution is far better in this case.

[crawworth]

Thanks Jim and Daniel.

Daniel, i'm going to check that solution thank you very much.

[jaikumar_f5]

This is thinking out of the box kind of solution 😉 but still I liked it.

Irule approach is clean and simple.