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Ryujin's avatar
Ryujin
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Sep 03, 2024

F5 Cluster IP addresses

Im trying to find clear documentation that tells me what requirements / restrictions we have on IP addresses that are required to operate a cluster. 

 

My main question is do the various addresses assigned to support the cluster require being in the same subnet. 

 

The design that we are looking at roughly is 

 

4 Velos appliances (2 in each DC). There will be a tenant on each appliance which will be clustered together. Ideally we prefer not to stretch L2 and operate with L3 as much as possible. So i want to confirm if appliances in DC1 can reside on 1 subnet and appliances in DC2 can reside on another subnet.

Each Tenant would essentially be on a stick / one-arm for data. All traffic would come in and leave on the same interface. The F5 does not directly sit in any of the networks where servers reside. I will be using BGP & RHI to inject routes into the rest of the network to ensure traffic finds the correct active F5. 

 

for example

F5a-DC1-Ten1a = VLAN-HA - 172.28.0.1 and VLAN-Routed - 192.168.250.1

F5b-DC1-Ten1b = VLAN-HA - 172.28.0.2 and VLAN-Routed - 192.168.250.2

F5a-DC2-Ten1a = VLAN-HA - 172.29.0.1 and VLAN-Routed - 192.168.251.1

F5a-DC2-Ten1b = VLAN-HA - 172.29.0.2 and VLAN-Routed - 192.168.251.2

 

Sorry if I've not made much sense. 

  • For HA configuration each F5 has to have a self IP from the same subnet as well as the shared floating IP. The only exception to this is the BIG-IP DNS configuration in which each unit is a single unit and they participate in a sync-group for DNS.

    • Ryujin's avatar
      Ryujin
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      Thanks Paulius

       

      Would the same be true for a sync-only group? Could I have 2 separate clusters at each DC but then a sync-only group between both clusters even though they reside on different networks?