Serverless NEG

Google Cloud Network Endpoint Groups – NEG

~ Last updated on : ~ jayendrapatil

Google Cloud Network Endpoint Groups – NEG

  • Network Endpoint Groups (NEG) is a configuration object that specifies a group of backend endpoints or services.
  • Network Endpoint Groups provides a logical grouping of IP addresses and ports for software services instead of entire VMs.
  • NEGs let you distribute traffic to your load balancer’s backends at a more granular level (for example, load balancing traffic at the Pod level instead of at the VM-level for GKE workloads).
  • NEGs can be used as backends for Application Load Balancers (HTTP/HTTPS), Proxy Network Load Balancers (TCP/SSL), Passthrough Network Load Balancers, and with Cloud Service Mesh (formerly Traffic Director).
  • Google Cloud supports six types of NEGs: Zonal, Internet, Serverless, Hybrid connectivity, Private Service Connect, and Port mapping.

Zonal NEG

  • contains one or more endpoints that can be Compute Engine VMs or services running on the VMs.
  • are zonal resources that represent collections of either IP addresses or IP address/port combinations for Google Cloud resources within a single subnet.
  • Supports two endpoint types:
    • GCE_VM_IP – IP only: resolves to the primary internal IPv4 address of a VM’s network interface.
    • GCE_VM_IP_PORT – IP:Port: resolves to either the primary internal IPv4 address or an internal IPv4 address from an alias IP range (e.g., Pod IPv4 addresses in VPC-native GKE clusters).
  • Only GCE_VM_IP_PORT type endpoints support IPv4 and IPv6 (dual-stack) zonal NEGs.
  • All other backends in that backend service must also be zonal NEGs.
  • Zonal NEG can be used as a backend for more than one backend service.
  • Backend services using zonal NEGs for backends only support balancing modes of RATE or CONNECTION. UTILIZATION is not supported.
  • Supports centralized health checks for NEGs with GCE_VM_IP_PORT and GCE_VM_IP endpoints.
  • Supported by:
    • Internal and External Passthrough Network Load Balancers (GCE_VM_IP endpoints)
    • Regional/Cross-region Internal and External Proxy Network Load Balancers (GCE_VM_IP_PORT endpoints)
    • Internal, External, and Classic Application Load Balancers (GCE_VM_IP_PORT endpoints)
    • Global external Proxy Network Load Balancer (GCE_VM_IP_PORT endpoints)
    • Cloud Service Mesh (GCE_VM_IP_PORT endpoints)

Internet NEG

  • contains endpoints that are hosted outside of Google Cloud, specified by hostname FQDN:port or IP:port.
  • Supports two endpoint types:
    • INTERNET_IP_PORT – IP:Port, where IP must not be an RFC 1918 address.
    • INTERNET_FQDN_PORT – FQDN:Port.
  • Can be global or regional in scope:
    • Global internet NEGs – contain a single endpoint; health checks not supported.
    • Regional internet NEGs – support up to 256 endpoints; use distributed Envoy health checks.
  • Ideal to serve content from an origin hosted outside of Google Cloud that needs to be fronted by an external Application Load Balancer.
  • Allows you to:
    • Use Google Edge infrastructure for terminating the user connection.
    • Direct the connections to your custom origin.
    • Use Cloud CDN for your custom origin.
    • Deliver traffic to the public endpoint across Google’s private backbone, improving reliability and decreasing latency.
  • Supported by:
    • Global internet NEGs: Cloud CDN, Global/Classic external Application Load Balancer, Cloud Service Mesh
    • Regional internet NEGs: Regional external/internal Application Load Balancer, Regional external/internal Proxy Network Load Balancer

Serverless NEG

  • points to Cloud Run, App Engine, Cloud Run functions (formerly Cloud Functions), or API Gateway services residing in the same region as the NEG.
  • Endpoint type is SERVERLESS.
  • Serverless NEGs don’t contain traditional endpoints – they reference FQDN belonging to the serverless resource.
  • Contains a single endpoint and is regional in scope.
  • Health checks are not applicable (managed by the serverless platform).
  • Supported by:
    • Global/Classic/Regional external Application Load Balancers
    • Regional/Cross-region internal Application Load Balancers (Cloud Run and Cloud Run functions 2nd gen only)

Hybrid Connectivity NEG

  • contains one or more endpoints that resolve to on-premises services, server applications in another cloud, or other internet-reachable services outside Google Cloud.
  • Endpoint type is NON_GCP_PRIVATE_IP_PORT – IP:Port belonging to a VM that is not in Compute Engine and must be routable using hybrid connectivity (Cloud Interconnect, Cloud VPN, or Router appliance).
  • Zonal in scope with one or more endpoints.
  • Health checks:
    • Centralized health checks – when used with Global/Classic external Application Load Balancer, Global external/Classic Proxy Network Load Balancer.
    • Distributed Envoy health checks – when used with Regional external/internal Application Load Balancer, Regional external/internal Proxy Network Load Balancer, Cross-region internal Application/Proxy Network Load Balancer.
  • Supported by:
    • External Application Load Balancers (Global, Classic, Regional)
    • Internal Application Load Balancers (Regional, Cross-region)
    • External Proxy Network Load Balancers (Global, Classic, Regional)
    • Internal Proxy Network Load Balancers (Regional, Cross-region)
    • Cloud Service Mesh

Private Service Connect NEG

  • resolves to a Google-managed regional or global API endpoint, or a managed service published using Private Service Connect.
  • Endpoint type is PRIVATE_SERVICE_CONNECT.
  • Contains a single endpoint and is regional in scope.
  • Health checks are not applicable.
  • Enables consumers to access managed services privately from inside their VPC network through a load balancer.
  • Supported by:
    • Global external Application Load Balancer (not supported by Classic Application Load Balancer)
    • Regional external Application Load Balancer
    • Regional/Cross-region internal Application Load Balancer
    • Global external Proxy Network Load Balancer (not supported by Classic Proxy Network Load Balancer)
    • Regional external/internal Proxy Network Load Balancer
    • Cross-region internal Proxy Network Load Balancer

Port Mapping NEG

  • provides a mapping from a client port of a Private Service Connect endpoint to a combination of service port and service producer VM.
  • Endpoint type is GCE_VM_IP_PORTMAP.
  • Contains one or more endpoints and is regional in scope.
  • Health checks are not applicable.
  • Routes traffic to a service producer VPC network through a connection between a Private Service Connect endpoint and a service attachment.
  • Used with Private Service Connect port mapping services.

NEG Comparison Summary

  • Zonal and Internet NEGs define how endpoints should be reached, whether they are reachable, and where they are located.
  • Serverless and Private Service Connect NEGs don’t contain traditional IP endpoints.
  • Hybrid connectivity NEGs point to services running outside Google Cloud, reachable via Cloud Interconnect or Cloud VPN.
  • Port Mapping NEGs are specifically for Private Service Connect port mapping use cases.

Google Cloud Network Endpoint Groups

GCP Certification Exam Practice Questions

  • Questions are collected from Internet and the answers are marked as per my knowledge and understanding (which might differ with yours).
  • GCP services are updated everyday and both the answers and questions might be outdated soon, so research accordingly.
  • GCP exam questions are not updated to keep up the pace with GCP updates, so even if the underlying feature has changed the question might not be updated
  • Open to further feedback, discussion and correction.
  1. A company needs to route traffic from their external HTTP(S) load balancer to an application running on-premises, connected via Cloud Interconnect. Which type of NEG should they use?
    1. Zonal NEG
    2. Internet NEG
    3. Hybrid connectivity NEG
    4. Private Service Connect NEG
    Show Answer

    Answer: c. Hybrid connectivity NEG – Hybrid connectivity NEGs use NON_GCP_PRIVATE_IP_PORT endpoints for on-premises or multi-cloud backends reachable via Cloud Interconnect or Cloud VPN.

  2. Which NEG type allows you to access a managed service published via Private Service Connect through a load balancer?
    1. Serverless NEG
    2. Internet NEG
    3. Private Service Connect NEG
    4. Zonal NEG
    Show Answer

    Answer: c. Private Service Connect NEG – PSC NEGs resolve to Google-managed API endpoints or managed services published using Private Service Connect.

  3. A team wants to load balance traffic to their Cloud Run service using an external Application Load Balancer. Which NEG type should they configure?
    1. Zonal NEG with GCE_VM_IP_PORT
    2. Serverless NEG
    3. Internet NEG
    4. Hybrid connectivity NEG
    Show Answer

    Answer: b. Serverless NEG – Serverless NEGs point to Cloud Run, App Engine, Cloud Run functions, or API Gateway services.

  4. Which balancing modes are supported by backend services that use zonal NEGs? (Choose 2)
    1. UTILIZATION
    2. RATE
    3. CONNECTION
    4. BANDWIDTH
    Show Answer

    Answer: b, c – Backend services using zonal NEGs only support RATE or CONNECTION balancing modes. UTILIZATION is not supported.

  5. Which of the following NEG types supports distributed Envoy health checks for regional load balancers? (Choose 2)
    1. Serverless NEG
    2. Regional Internet NEG
    3. Hybrid connectivity NEG
    4. Private Service Connect NEG
    Show Answer

    Answer: b, c – Regional Internet NEGs and Hybrid connectivity NEGs (when used with regional load balancers) support distributed Envoy health checks.

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