Connection timeout from CloudBuild to GRPC on GKE

[yerinu2023]

I'm getting the following error when gRPC client on CloudBuild calls gRPC server on GKE.

UNAVAILABLE: Connection timeout for priority cloud-internal-istio:cloud_mp_493914004039_1122741154809425496[child1].

I have resolved GRPC server XDS resolution permission issue between CloudBuild and Traffic Director, so I suspect timeout could be relate to firewall blocking from CloudBuild to GRPC server on GKE.

I have the following firewall rule for health check from traffic director to GRPC server.

gcloud compute firewall-rules create grpc-gke-allow-health-checks \
--network default --action allow --direction INGRESS \
--source-ranges 35.191.0.0/16,130.211.0.0/22 \
--target-tags allow-health-checks \
--rules tcp:50051-50052

I guess this firewall rule might not include connection from CloudBuild to GRPC server waiting on port 50051.

Any help would be appreciated.

Thanks