Can DNS point to specific port?
app1 service running on Nodeport: 30001
app2 service running on Nodeport: 30002
app1 endpoint DNS should be www.app1.com
app2 endpoint DNS should be www.app2.com
You need use LoadBalancer type service instead of NodePort type.But creating a new load balancer for each and every app is costly so alternatively you can use kubernetes ingress. There are different ingress controllers such as nginx which implements the ingress API.