target pools vs backend services vs regional backend service difference?

Question

While exploring google cloud platform's Load balancer options Advanced Menu shows multiple options which are a bit confusing.

there are multiple backends

• backend service -> HTTP(S) LB
• backend bucket -> HTTP(S) LB
• regional backend service -> internal LB
• target pools -> TCP LB

Just going through documentations for target pools and backend-service Looks to me they have similar parameters to configure and in the basic menu both are listed as backends.

I understand that target pools are used by TCP forwarding rules where as backend-service used by url map ( http/s Load balancer).

But Are there any other difference between these or is it just names?

Answer 1

A Backend Bucket allow you to use Google Cloud Storage bucket with HTTP(S) load balancing. It can handle request for static content. This option would be useful for a webpage that with static content and it would avoid the costs of resources than a instance would need.

The Backend Service is a centralized service that manages backends, which in turn manage an indeterminate number of instances that handle user requests.

The Target Pools resource defines a group of instances that should receive incoming traffic from forwarding rules. When a forwarding rule directs traffic to a target pool, Google Compute Engine picks an instance from these target pools based on a hash of the source IP and port and the destination IP and port.

This is why they both are listed as backend-services, because at the end they both do the same, but they specify for two different kind of load balancer. The backend service works for HTTP(S) load balancer and target pools are used for forwarding rules.