The question is at what level do you partition the connection. I could setup a server and then vend an IP to the clients. The problem with that strategy is how do you do recovery? Particularly in an environment where you treat machines like cattle.
If you don't vend an IP, then you need to build a load balancer of sorts to sit between the client and the game instance server. Alas, how do you find that game instance server? If you have a direct mapping, sticky header, or consistent routing. As long as you care about that server's state, it is the same as vending an IP to the client except you can now absorb DOS attacks and offload a bit of compute (like auth) to the load balancer fleet.
The hard problem is how much do you care about that server's lifetime? Well, we shouldn't because individual servers are cattle, and we can solve some of the cattle problems by having a nice shutdown to migrate state and traffic away. This will help for operator induced events with kindness. Machine failures, kernel upgrades, and other such things that affect the host may have other opinions.
If you don't vend an IP, then you need to build a load balancer of sorts to sit between the client and the game instance server. Alas, how do you find that game instance server? If you have a direct mapping, sticky header, or consistent routing. As long as you care about that server's state, it is the same as vending an IP to the client except you can now absorb DOS attacks and offload a bit of compute (like auth) to the load balancer fleet.
The hard problem is how much do you care about that server's lifetime? Well, we shouldn't because individual servers are cattle, and we can solve some of the cattle problems by having a nice shutdown to migrate state and traffic away. This will help for operator induced events with kindness. Machine failures, kernel upgrades, and other such things that affect the host may have other opinions.