Load Balancer
Exposes the service externally using a cloud provider’s load balancer. NodePort and ClusterIP services, to which the external load balancer will route, are automatically created.
When would you use this?
If you want to directly expose a service, this is the default method. All traffic on the port you specify will be forwarded to the service. There is no filtering, no routing, etc. This means you can send almost any kind of traffic to it, like HTTP, TCP, UDP, Websockets, gRPC, or whatever.
The big downside is that each service you expose with a LoadBalancer will get its own IP address, and you have to pay for a LoadBalancer per exposed service, which can get expensive!
Ingress Controller
Ingress is actually NOT a type of service. Instead, it sits in front of multiple services and act as a “smart router” or entrypoint into your cluster.
You can do a lot of different things with an Ingress, and there are many types of Ingress controllers that have different capabilities such as AWS Application load balancer (ALB)
When would you use this?
Ingress is probably the most powerful way to expose your services, but can also be the most complicated. There are many types of Ingress controllers, from the AWS Application Load Balancer, Nginx, Contour, Istio, and more. There are also plugins for Ingress controllers, like the cert-manager, that can automatically provision SSL certificates for your services.
Ingress is the most useful if you want to expose multiple services under the same IP address, and these services all use the same L7 protocol (typically HTTP). and because Ingress is “smart” you can get a lot of features out of the box (like SSL, Auth, Routing, etc)