GCP Architecture Reference

Architecture Diagram

Terraform Structure

SGP’s GCP infrastructure is provisioned in two separate Terraform phases with different privilege levels:

Phase	Directory	Credentials	Scope
Privileged bootstrap	`projectsetup/`	Your personal GCP identity	Service account, Artifact Registries, API enablement
Deprivileged main infra	`deployments/<name>/`	Terraform service account (read from Secret Manager)	GKE, Cloud SQL, networking, IAM, secrets

The main infrastructure Terraform reads the service account key directly from Secret Manager — no key file needs to exist on disk during the infrastructure run.

Resources by Type

Compute Resources

Resource	Count	Purpose
GKE Cluster	1	Kubernetes orchestration
System Node Pool (`default`)	1	System pods — tainted `CriticalAddonsOnly`
CPU Node Pool (`cpu`)	1	Application workloads
GPU Node Pool (`gpu`)	0–1	AI/ML workloads (optional)
Cassandra Node Pool	0–1	Temporal database (optional)
Bastion Host	0–1	Private cluster access via IAP (optional)

Default node pool sizing:

Pool	Machine Type	Min Nodes	Max Nodes
System (`default`)	`n2-standard-4`	3	10
CPU (`cpu`)	`n2-standard-16`	4	30
GPU (`gpu`)	`a2-highgpu-1g`	0	0 (disabled by default)
Cassandra	`n2-standard-4`	3	6

All pools use COS_CONTAINERD image type and are preemptible by default (configurable via node_pool_config.preemptible).

Network Resources

Resource	Count	Purpose
VPC Network	1	Network boundary
Subnetwork	1	Kubernetes nodes
Secondary IP Ranges	2	GKE pod and service CIDRs
Cloud DNS Zone	1	Internal + external name resolution
Global Static IP	1	Load balancer ingress endpoint
SSL Policy	1	Minimum TLS 1.2 enforcement
Firewall Rules	4–5	Traffic control (offline mode)
VPC Peering	1	Private connectivity to Cloud SQL
Private Route	0–1	Google APIs access in offline mode

Data & Storage Resources

Resource	Count	Purpose
Cloud SQL (PostgreSQL 17)	1	Main platform database
Cloud SQL (PostgreSQL 17)	1	Temporal workflow database
GCS Bucket (main)	1	Platform object storage
GCS Bucket (knowledge base)	1	KB document storage
GCS Bucket (monitoring)	0–1	Observability data (optional)
Vertex AI Vector Search Index	0–N	Vector embeddings (optional)
Cloud Firestore	0–1	Agentex state (optional)

Both Cloud SQL instances are private-only (no public IP) and connected to the VPC via VPC peering. SSL is enforced for all database connections (ENCRYPTED_ONLY).

Security Resources

Resource	Count	Purpose
Secret Manager Secrets	10+	Platform configuration and credentials
Cloud KMS Key Ring + Key	0–1	Customer Managed Encryption Keys (optional)
Service Account (`sgp-<workspace_id>-sa`)	1	Main SGP workload identity SA
Service Account (`sgp-<workspace_id>-node-pool-creator`)	1	Node pool creation SA
Service Account (`sgp-tf-lp-<name>`)	1	Terraform execution SA (projectsetup)
Workload Identity Pool	1	GKE pod → GCP SA binding
IAP Tunnel (Bastion)	0–1	Private cluster access

Artifact Resources (projectsetup phase)

Resource	Count	Purpose
Artifact Registry (Docker)	1	SGP container images
Artifact Registry (Helm)	1	SGP Helm charts

Both registries are named sgp-<workspace_id>-docker-repository and sgp-<workspace_id>-helm-repository.

Monitoring Resources

Resource	Count	Purpose
Cloud Logging	1	GKE system components, API server, workloads
VPC Flow Logs	0–1	Network traffic sampling (optional)
GKE Vulnerability Scanning	1	Basic vulnerability mode enabled by default

Network Architecture

Address Space

VPC: sgp-<workspace_id>-network
└── Subnet: sgp-<workspace_id>-network-kubernetes-subnet
    ├── Primary range:   10.0.0.0/16   (65,536 IPs — GKE nodes)
    ├── Secondary range: 10.2.0.0/16   (65,536 IPs — Kubernetes services)
    └── Secondary range: 10.4.0.0/16   (65,536 IPs — Kubernetes pods)

Cloud SQL VPC Peering:
    └── Reserved range:  /16 block      (managed by service networking)

GKE Control Plane (private):
    └── Master CIDR:     10.5.0.0/28   (configurable via private_gke_master_ipv4_cidr_block)

Traffic Flow

Ingress (External):

Internet → Global Load Balancer (static IP) → Istio Ingress → Pod
(TLS terminated at load balancer; SSL policy enforces TLS 1.2+)

Database Access:

GKE Pod → VPC Peering → Cloud SQL (private IP)
(SSL enforced; no public IP on Cloud SQL instances)

Google APIs (offline mode):

GKE Pod → Private Google Access → Google APIs (199.36.153.4/30)
(Dedicated route; no default internet gateway route created)

Bastion Access:

Engineer → IAP Tunnel → Bastion VM (e2-micro) → GKE API (private endpoint)

GKE Configuration

Cluster Features

Feature	Value
Datapath provider	`ADVANCED_DATAPATH` (eBPF-based)
IP stack	Dual-stack IPv4/IPv6
Workload Identity	Enabled (`<project>.svc.id.goog`)
Secret Manager integration	Enabled
Vulnerability scanning	Basic mode
Private nodes	Enabled (when `offline_mode = true`)
Private endpoint	Configurable (`enable_gke_private_endpoint`)
Master authorized networks	Configurable per deployment
DNS endpoint	Enabled (allows external cluster DNS access)

Workload Identity

GKE pods authenticate to GCP services using Workload Identity rather than node-level service account keys. Kubernetes service accounts are bound to GCP service accounts via the workload identity pool:

<project>.svc.id.goog[<namespace>/<k8s-service-account>]
  → GCP Service Account
    → Secret Manager, GCS, Artifact Registry, etc.

Key bindings provisioned by Terraform:

Kubernetes Identity	GCP Role
`sgp-system-manager` (system-manager namespace)	`secretmanager.viewer`, `secretmanager.secretAccessor`
`sgp-system-manager-pre-install`	`secretmanager.viewer`, `secretmanager.secretAccessor`
`egp-api-backend` (egp namespace)	`secretmanager.secretAccessor`, GCS access via SA impersonation
`egp-api-backend-db-setup`	`secretmanager.secretAccessor`
`agents` (agents namespace)	`secretmanager.secretAccessor`

Secret Manager Secrets

Key secrets provisioned by Terraform:

Secret Name	Contents
`<prefix>-system-manager-config`	System Manager runtime configuration (URLs, workspace ID, cloud provider info)
`<prefix>-system-manager-desired-state`	Initial desired state (pack list) — managed externally after first apply
`<prefix>-saml-config-secret`	SAML IdP configuration
`<prefix>-oidc-config-secret`	OIDC IdP configuration
`terraform-service-account-key-secret`	Terraform SA private key (used by `deployments/` as provider credentials)

The secret_name_prefix variable (typically sgp-<workspace_id>) scopes secrets for deployments in shared GCP projects.

Customer Managed Encryption Keys (CMEK)

When useCustomerManagedEncryptionKey = true, Terraform provisions a Cloud KMS key ring and symmetric encryption key:

Resource	Name
Key Ring	`sgp-<workspace_id>-key-ring`
Crypto Key	`sgp-<workspace_id>-crypto-key`

The key is applied to:

Cloud SQL instances (both main and Temporal)
GCS buckets

CMEK is recommended for production deployments to maintain cryptographic control over data at rest.

Optional Capabilities

Each optional capability provisions dedicated infrastructure:

Capability	Variable	Additional Resources
Agentex	`deployAgentex`	Firestore, dedicated service account, GCS bucket
Workflows	`deployCompass`	Cloud SQL database, GCS bucket, service account
Dex (Document Understanding)	`enable_dex`	Cloud SQL (`db-custom-4-15360`), GCS bucket, service account
Reducto	`enable_reducto`	Cloud SQL (`db-custom-2-7680`), GCS bucket, Vision API key, service account
Model Engine	`deployModelEngine`	Vertex AI, additional node pools
Monitoring	`enable_monitoring`	GCS bucket, IAM bindings
Cloud Build	`enable_cloud_build`	GCS bucket, Artifact Registry, service accounts
Vertex AI Search	`vertex_ai_indices`	Vector Search indices and endpoints
LiveKit	`provision_livekit_infrastructure`	GCS bucket (audio), IAM bindings

Overview

Getting Started

Infrastructure

Evaluations

Evaluation Dashboards

Tracing

Agents

GCP Architecture Reference

Architecture Diagram

Terraform Structure

Resources by Type

Compute Resources

Network Resources

Data & Storage Resources

Security Resources

Artifact Resources (projectsetup phase)

Monitoring Resources

Network Architecture

Address Space

Traffic Flow

GKE Configuration

Cluster Features

Workload Identity

Secret Manager Secrets

Customer Managed Encryption Keys (CMEK)

Optional Capabilities

​Architecture Diagram

​Terraform Structure

​Resources by Type

​Compute Resources

​Network Resources

​Data & Storage Resources

​Security Resources

​Artifact Resources (projectsetup phase)

​Monitoring Resources

​Network Architecture

​Address Space

​Traffic Flow

​GKE Configuration

​Cluster Features

​Workload Identity

​Secret Manager Secrets

​Customer Managed Encryption Keys (CMEK)

​Optional Capabilities

Architecture Diagram

Terraform Structure

Resources by Type

Compute Resources

Network Resources

Data & Storage Resources

Security Resources

Artifact Resources (projectsetup phase)

Monitoring Resources

Network Architecture

Address Space

Traffic Flow

GKE Configuration

Cluster Features

Workload Identity

Secret Manager Secrets

Customer Managed Encryption Keys (CMEK)

Optional Capabilities