import the XPO for cluster AOS

May I Know the best way to import the XPO to Cluster AOS for AX 2012 R3

I have AOS1, AOS2 Server which pointing to same DB .

IN order to import the XPO what are the best way to reflect the changes on both AOS server.

Stop one of the AOS servers. Block access to the other one, import the .xpo, compile full X++ and CIL and synchronize database. Then allow access again and start the other AOS.
But doing something like this sounds suspicious. XPO files are used for development, not for deployment, and development boxes don’t use clustered AOS. You should use models and modelstores for deployment.

Which mean even if the customer requires small modification you are suggesting me to do import the model and do full compile ? By importing the XPO I can fix the issue instantly. Advice me please

It’s the other way around. If you develop source code (.xpo), you have to compile the application. If you developed the binaries (modelstore), you already have X++ and CIL compiled.
And dealing with code changes in production and all the related issues is really something what you shouldn’t do in production. You should deliver the application that you prepared and tested, instead of just giving customers a piece of code.

Also please look at Deploying Customizations Across Microsoft Dynamics AX 2012 Environments (White paper) [AX 2012].