What are the differences between Network and HTTP(s) load balancer in GCP

Question

GCP provides two load balancers namely Network and HTTP(s) where the former works on layer 4 and the later works on layer 7.

There is also a documentation which states that even HTTP traffic can be load balanced by a network load balancer. This slightly confuses which load balancer to choose for a web app in GCP. It is better to understand the differences before selecting one for the project.

What are the differences between them based on the workflow, setup, region/zone based, options for session affinity, and other settings?

Answer 1

Network load balancer Vs HTTP(s) Load Balancer

+---------------------+------------------------------------------+------------------------------------------------------+ |       Category      |       Network Load Balancing (NLB)       |             HTTP(S) Load Balancing (HLB)             | +---------------------+------------------------------------------+------------------------------------------------------+ |     1. Region /     | NLB supports only within a region.       | HLB supports both within cross-region                | |     Cross-Region    | Does not support cross-region            | load balancing.                                      | |                     | load balancing                           |                                                      | +---------------------+------------------------------------------+------------------------------------------------------+ |  2. Load balancing  | NLB is based on IP address, port         | HLB is based only on HTTP and HTTPS                  | |       based on      | and protocol type. Any TCP/UDP           | protocols.                                           | |                     | traffic, even SMTP can be                |                                                      | |                     | load balanced.                           |                                                      | +---------------------+------------------------------------------+------------------------------------------------------+ |      3. Packet      | Packet inspection is possible and        | HLB cannot inspect packets.                          | |      inspection     | load balance based on packets            |                                                      | +---------------------+------------------------------------------+------------------------------------------------------+ |     4. Instance     | No need of creating instance group.      | Managed / UnManaged Instance group                   | |         Group       | Target pools need to be created.         | is necessary for creating HTTP / HTTPS               | |                     | Instance can be just tagged to the pool. | load balancer.                                       | |                     | Ideal for unmanaged instance group       |                                                      | |                     | where instances are non homogeneous.     |                                                      | +---------------------+------------------------------------------+------------------------------------------------------+ |     5. Workflow     | Forwarding rules is the starting point.  | This is quite complex in HTTP(s) load balancer.      | |                     | It directs the request to the            | Global forwarding rulesroutes direct the request     | |                     | target pools from which compute          | to target HTTP proxy, which in turn checks the       | |                     | engines will pick the request.           | URL map to determine appropriate backend             | |                     |                                          | services.  These services in turn direct the request | |                     | Forwarding rules -> target pool          | to the instance group.                               | |                     |  -> instances                            |                                                      | |                     |                                          |                                                      | |                     |                                          | Global forwarding rules -> Target HTTP proxy ->      | |                     |                                          | URL map -> Backend Sevices -> instance group         | +---------------------+------------------------------------------+------------------------------------------------------+ |     6. Types of     | Basic network load balancer which        | 1. Cross-region load balancer uses only one          | |    load balancer    | directs the request based on IP address, | global IP address and routes the request             | |                     | port and the protocol within the region. | to the nearest region.                               | |                     |                                          |                                                      | |                     |                                          | 2. Content-based load balancer is based              | |                     |                                          | on the URL path. Different path rules need           | |                     |                                          | different backend services. for eg: /video           | |                     |                                          | and /static require two separate backend services.   | +---------------------+------------------------------------------+------------------------------------------------------+ | 7. Session affinity | Session affinity can be set, but only    | 1. Client IP Affinity: This directs the same         | |                     | during the creation of target pool.      | client ip to same backend instance by                | |                     | Once it is set, the value                | computing hash of the IP.                            | |                     | cannot be changed.                       | 2. Generated Cookie Affinity: Load balancer stores   | |                     |                                          | cookie in clients and directs the same client to     | |                     |                                          | same instance with the help of retrieved cookie.     | +---------------------+------------------------------------------+------------------------------------------------------+ |   8. Health check   | Health check is optional, but network    | Health can be verified by either using HTTP          | |                     | load balancing relies on HTTP Health     | heath check or HTTPS health check.                   | |                     | checks for determining instance health.  |                                                      | +---------------------+------------------------------------------+------------------------------------------------------+ 

The above table is based on my perspective. If anything is incorrect or If I had missed something, please feel free to comment and I will add it to the table.

Here is the link for instructions on setting up an HTTP load balancer in GCP.