Hi Aaron,
we have the exact same challange... We have a DR-site with same IP addresses, vlan etc. So the config should be exactly the same. We took the approach first to make a backup of the F5 cluster on our primary site and install it on the DR site F5. But that came with alot of other problems, one example is that the mgmt-port is not the same because we need to manage the devices out-of-band and that failed first with routing and interface setup not matching 100%. Also there was a bug that we ran into: https://support.f5.com/kb/en-us/solutions/public/15000/800/sol15835.html
So that approach did not seem to work for us. So now we are looking into other options, but we are stuck. I would be very interested in using the API to sync the config, between the sites. But we cannot create a new application to make changes to both the enviroments as we are very dependent on the GUI today because we have other people than ourselves in the network-team working in the BigIPs. So it would be nice with some function that could take all the config changes done and push them to the other F5 cluser on the DR site. But im not that familiar with the API yet so im not sure if that would even work? An idea is just to export all Nodes, Pools, VIPs etc. and diff them to the other cluster then add the missing ones. BUT then the question becomes could you do this through the API with for example certificates, persistence policys, http profiles etc. it becomes quite complex when you need a full config sync.
This should not be that hard really? But it seems like the BigIP product is not built for HA in multiple datacenters if you dont want to make the changes done in one F5 cluster then add it to the other manually. I red about sync-only groups but it will not suit our current production enviroment as we already use multiple partitions and folders. As i understand it you will need a seperate folder for the sync-only objects? So that is not possible im afraid.
We continue to search for a solution for this, but in the meantime its just old fasion manual work. :)