About Private Service Connect backends

You can access Google APIs and published services by creating a Private Service Connect endpoint (based on a forwarding rule) or a Private Service Connect backend (based on a load balancer). This guide focuses on Private Service Connect backends.

Private Service Connect backends use a load balancer configured with Private Service Connect network endpoint group (NEG) backends. This configuration was previously referred to as a Private Service Connect endpoint with consumer HTTP(S) service controls.

Accessing APIs and services through a consumer-managed load balancer provides several benefits. Load balancers can act as a centralized policy enforcement point where security or routing policies are enforced. They provide centralized metrics and logging that a published service might not provide, and they allow consumers to control their own routing and failover.

Figure 1 shows a load balancer with a Private Service Connect NEG connecting to a published service. Client traffic goes to a load balancer that processes the traffic and then routes it to a Private Service Connect backend that maps to a published service that runs in a different VPC network.

Figure 1. Using a global external Application Load Balancer lets service consumers with internet access send traffic to services in the service producer's VPC network (click to enlarge).

Deployment overview

To access APIs and services through Private Service Connect backends, do the following:

  1. Identify the API or service that you want to connect to.

    For Google APIs: Select a regional service endpoint.

    For published services: Ask the service producer for the service attachment URI.

  2. Deploy a load balancer to send traffic to your published service. Choose a load balancer that fits your requirements, including whether you have internet clients, internal clients, or require regional isolation. You can also reuse an existing load balancer.

  3. Deploy the Private Service Connect NEGs and add them to your load balancer backend service. Create Private Service Connect NEGs that reference your published service. Then add the NEGs to the load balancer's backend service so that the load balancer can send them traffic.

Supported load balancers and targets

You can use a backend to access a published service or a regional Google API.

See the load balancing documentation for more information about the load balancer that you want to add a Private Service Connect backend to.

Published service targets

A Private Service Connect backend for published services requires two load balancers—a consumer load balancer and a producer load balancer. This table describes the compatibility between different types of consumer and producer load balancers, including which backend-service protocols are compatible with the consumer load balancers. Each row represents a type of consumer load balancer, and each column represents a type of producer load balancer.

In the following tables, a checkmark indicates that a feature is supported, and a no symbol indicates that a feature isn't supported.

Consumer load balancer and supported consumer backend-service protocols Producer load balancer
Internal passthrough Network Load Balancer Regional internal Application Load Balancer Regional internal proxy Network Load Balancer

Global external Application Load Balancer (supports multiple regions)

Protocols: HTTPS, HTTP2

Note: Classic Application Load Balancer is not supported.

Regional external Application Load Balancer

Protocols: HTTP, HTTPS, HTTP2

Regional internal Application Load Balancer

Protocols: HTTP, HTTPS, HTTP2

Cross-region internal Application Load Balancer (Preview)

Protocols: HTTPS, HTTP2

Regional internal proxy Network Load Balancer

Protocol: TCP

Cross-region internal proxy Network Load Balancer

Protocol: TCP

Regional external proxy Network Load Balancer

Protocol: TCP

Global external proxy Network Load Balancer (Preview)

Protocol: TCP/SSL

Note: Classic proxy Network Load Balancer is not supported.

This table describes the configuration for the producer load balancers that are supported by Private Service Connect backends.

Configuration Producer load balancer
Internal passthrough Network Load Balancer Regional internal Application Load Balancer Regional internal proxy Network Load Balancer
Supported producer backends
  • GCE_VM_IP NEGs
  • Instance groups
  • GCE_VM_IP_PORT NEGs
  • Hybrid NEGs
  • Serverless NEGs
  • Private Service Connect NEGs
  • Instance groups
  • GCE_VM_IP_PORT NEGs
  • Hybrid NEGs
  • Serverless NEGs
  • Private Service Connect NEGs
  • Instance groups
Forwarding rule protocols
  • TCP
  • HTTP
  • HTTPS
  • HTTP/2
  • TCP
Forwarding rule ports The forwarding rule must refer to a single port. The forwarding rule must refer to a single port. The forwarding rule must refer to a single port.
PROXY protocol

For an example backend configuration that uses a global external Application Load Balancer, see Access published services through backends.

Google API targets

This table describes which load balancers can use a Private Service Connect backend to access Google APIs.

For an example configuration that uses an internal Application Load Balancer, see Access Google APIs through backends.

Configuration Details
Consumer configuration (Private Service Connect backend)
Supported consumer load balancers

  • Internal Application Load Balancer

    Protocols: HTTPS

  • Regional external Application Load Balancer

    Protocols: HTTPS

Producer
Supported services Supported regional Google APIs

Different load balancers support different port configurations; some load balancers support a single port, some support a range of ports, and some support all ports. For more information, see Port specifications.

Specifications

All Private Service Connect backends have the following specifications:

  • Private Service Connect NEGs cannot be mixed with other NEG types in the same backend service. However, self-hosted applications and managed services can both be backends of the same load balancer as long as they are part of separate backend services.
  • Backend services with Private Service Connect NEGs do not support health checks. Health check resources are not configured with backend services used for Private Service Connect.
  • Only the supported load balancers can use Private Service Connect NEGs as backends.

Private Service Connect backends that use global external Application Load Balancers have additional specifications:

  • Multiple Private Service Connect NEGs can be in the same backend service as long as they are from different regions. You can't add multiple Private Service Connect NEGs from the same region to the same backend service.
  • Private Service Connect NEGs are automatically configured with outlier detection. Outlier detection lets the load balancer detect failures in published service responses and fail over to remaining healthy regions. The default outlier detection policy can be overridden by applying your own outlier detection configuration to the backend service.

Pricing

For pricing information, see the following sections of the VPC pricing page:

What's next