How to allow traffic from node to internet via firewall?

Hi All,
Many applications are running on multiple nodes in a cluster and now i wants to allow port X to internet via firewall but i cant allow all node ips on firewall so how can route the traffic to internet? I dont want to increase the cost by separating the nodes or creating a different subnet on same cluster. Also i cant map the node ip on firewall because if node will be down then my application will run on new node.

Cloud being used: bare metal
Host OS: ubuntu

You need something like this This is another option too