Active-Active DC cookie persistence

Hi team,

 

We have two DC, let us call them DC01 and DC02

 

One of HTTPs-based app requires active-active from GLSB point of view and cookie persistence is used to assure the traffic is always sent to the same pool member.

 

We understand the cookie encoding as F5 KB https://support.f5.com/csp/article/K6917. So we have the same pool member setup including local-site pool members and remote-site pool member with Cookie Insert at both DC. The inserted cookie is set up exactly same on LTMs in both DCs.(We proved that app client browser do get the same cookie (same name and same value) from vIP in DC01 and vIP in DC02).

 

But we still have issue with cookie persistence:

 

For example, when client session is connected to vIP at DC01 initially. When DNS cache timeout and DNS response of new DNS query points client to vIP at DC02, client will experienced 401 error. We can see all client subsequent requests have F5 inserted cookie included. But It looks like that the cookie which is inserted by LTM in the DC01 is not recognized by the LTM in the DC02. So cookie persistence is failed to send the traffic to the same pool member.

 

any clue of cause of our issue?