Configure a global Cloud Load Balancing backend service in Application Design Center

The Global Cloud Load Balancing (Backend) component helps you manage load balancer traffic distribution settings, including the protocol used to connect to backends, session settings, health checks, and timeouts. These settings provide fine-grained control over how your load balancer behaves. You can configure the following backends:

  • Serverless NEG: A list of serverless Cloud Run or Cloud Run functions applications as backends.

  • Managed Instance Group (MIG): A list of Compute Engine instance groups as backends.

For more information, see Backend services overview.

This document describes the parameters you can configure when using App Design Center to create a global Cloud Load Balancing backend.

Required configuration parameters

If your template includes a global Cloud Load Balancing backend component, you must configure the following parameters before you deploy.

Parameter name

Description and constraints

Background information

Name

 Name for the load balancer backend service. name

Project ID

The project where you want to deploy the Cloud Load Balancing backend service.

 Configure components

Optional configuration parameters

The following parameters are optional. To display advanced parameters, in the Configuration area, select Show advanced fields.

Feature

Parameter name

Description and constraint information

Background information

Host Path Mappings

 Host Configure URL maps Use URL maps
Path Configure URL maps Use URL maps
Load Balancing Scheme loadBalancingScheme Backend services overview
Protocol protocol Protocol to the backends
Port Name portName Named ports
Description A description for the backend service. description
Enable CDN enableCDN Cloud CDN overview
Compression Mode compressionMode Compression isn't working
Custom Request Headers customRequestHeaders[] Create custom headers in backend services
Custom Response Headers customResponseHeaders[] Create custom headers in backend services
Connection Draining Timeout Sec connectionDraining.drainingTimeoutSec Enable connection draining
Session Affinity sessionAffinity Session affinity
Affinity Cookie TTL Sec affinityCookieTtlSec Generated cookie affinity
Locality LB Policy localityLbPolicy Load balancing locality policy
Timeout Sec timeoutSec Backend service timeout

Log config

 Enable logConfig.enable Logging
Sample Rate logConfig.sampleRate Logging

Groups

 Group backends[].group Backends
Description A description for the backends group. backends[].description
Balancing Mode backends[].balancingMode Balancing modes and target capacity settings
Capacity Scaler backends[].capcityScaler Capacity scaler
Max Connections backends[].maxConnections Connection balancing mode
Max Connections Per Instance backends[].maxConnectionsPerInstance Connection balancing mode
Max Connections Per Endpoint backends[].maxConnectionsPerEndpoint Connection balancing mode
Max Rate backends[].maxRate Rate balancing mode
Max Rate Per Instance backends[].maxRatePerInstance Rate balancing mode
Max Rate Per Endpoint backends[].maxRatePerEndpoint Rate balancing mode
Max Utilization backends[].maxUtilization Utilization balancing mode

Serverless NEG backends

 Region region Serverless network endpoint groups overview
Type The type of serverless backend. Possible values include cloud-run, cloud-function, or app-engine. Supported load balancers
Service Name appEngine.service Serverless network endpoint groups overview
Service Version appEngine.version Serverless network endpoint groups overview

IAP Config

 Enable iap.enabled Identity-Aware Proxy overview
OAuth2 Client ID iap.oauth2ClientId How to share OAuth clients
OAuth2 Client Secret iap.oauth2ClientSecret How to share OAuth clients

CDN Policy

 Cache Mode cdnPolicy.cacheMode Caching overview
Signed URL Cache Max Age Sec cdnPolicy.signedUrlCacheMaxAgeSec Customize the maximum cache time
Default TTL cdnPolicy.defaultTtl Change TTL settings and overrides
Max TTL cdnPolicy.maxTtl Change TTL settings and overrides
Client TTL cdnPolicy.clientTtl Change TTL settings and overrides
Negative Caching cdnPolicy.negativeCaching Use negative caching
Serve While Stale cdnPolicy.serveWhileStale Serving stale content
Bypass Cache on Request Headers cdnPolicy.bypassCacheOnRequestHeaders[] Bypassing cache

Negative Caching Policy

 Code cdnPolicy.negativeCachingPolicy[].code Use negative caching
TTL cdnPolicy.negativeCachingPolicy[].ttl Use negative caching

Cache Key Policy

 Include Host cdnPolicy.cacheKeyPolicy.includeHost Cache keys
Include Protocol cdnPolicy.cacheKeyPolicy.includeProtocol Cache keys
Include Query String cdnPolicy.cacheKeyPolicy.includeQueryString Query string include list
Query String Blacklist cdnPolicy.cacheKeyPolicy.queryStringBlacklist[] Query string exclude list
Query String Whitelist cdnPolicy.cacheKeyPolicy.queryStringWhitelist[] Query string include list
Include HTTP Headers cdnPolicy.cacheKeyPolicy.includeHttpHeaders[] HTTP headers and HTTP cookies cache key settings
Include Named Cookies cdnPolicy.cacheKeyPolicy.includeNamedCookies[] Including named cookies

Outlier Detection

 Base Ejection Time Seconds outlierDetection.baseEjectionTime.seconds Outlier detection for serverless NEGs
Base Ejection Time Nanos outlierDetection.baseEjectionTime.nanos Outlier detection for serverless NEGs
Consecutive Errors outlierDetection.consecutiveErrors Outlier detection for serverless NEGs
Consecutive Gateway Failure outlierDetection.consecutiveGatewayFailure Outlier detection for serverless NEGs
Enforcing Consecutive Errors outlierDetection.enforcingConsecutiveErrors Outlier detection for serverless NEGs
Enforcing Consecutive Gateway Failure outlierDetection.enforcingConsecutiveGatewayFailure Outlier detection for serverless NEGs
Enforcing Success Rate outlierDetection.enforcingSuccessRate Outlier detection for serverless NEGs
Interval Seconds outlierDetection.interval.seconds Outlier detection for serverless NEGs
Interval Nanos outlierDetection.interval.nanos Outlier detection for serverless NEGs
Max Ejection Percent outlierDetection.maxEjectionPercent Outlier detection for serverless NEGs
Success Rate Minimum Hosts outlierDetection.successRateMinimumHosts Outlier detection for serverless NEGs
Success Rate Request Volume outlierDetection.successRateRequestVolume Outlier detection for serverless NEGs
Success Rate Stdev Factor outlierDetection.successRateStdevFactor Outlier detection for serverless NEGs

Health Check

 Host http2HealthCheck.host Additional flags for HTTP, HTTPS, and HTTP/2 health checks
Request Path http2HealthCheck.requestPath Success criteria for HTTP, HTTPS, and HTTP/2
Request sslHealthCheck.request ASuccess criteria for SSL and TCP
Response sslHealthCheck.response Additional flags for HTTP, HTTPS, and HTTP/2 health checks
Port http2HealthCheck.port Health check categories, protocols, and ports
Port Name http2HealthCheck.portName Named ports
Proxy Header http2HealthCheck.proxyHeader Headers
Port Specification http2HealthCheck.portSpecification Port specification flags
Protocol type Health check categories, protocols, and ports
Check Interval Sec checkIntervalSec Probes
Timeout Sec timeoutSec Probes
Healthy Threshold healthyThreshold Health state
Unhealthy Threshold unhealthyThreshold Health state
Logging logConfig.enable Health check logging information
Edge Security Policy edge_security_policy Edge security policies
Security Policy security_policy Security policy overview
Firewall Networks network Configure firewall rules
Firewall Projects Names of the projects to create firewall rules in. Configure firewall rules
Target Tags targetTags[] Restrict which clients can send traffic to the load balancer
Target Service Accounts targetServiceAccounts[] Source and target filtering by service account

What's next

To configure the fronted component, see Configure a global Cloud Load Balancing frontend in Application Design Center.