Terraform — GCP

Version: 0.1.0

Provision a production-ready GKE cluster for DecisionBox using the included Terraform module.

What It Creates

Resource	Description
VPC	Dedicated network with subnets for nodes, pods, and services
Cloud NAT	Outbound internet access for private nodes
Firewall rules	Internal traffic + GCP health check ranges
GKE cluster	Private nodes, Dataplane V2, auto-upgrade, shielded nodes
Node pool	Auto-scaling with configurable machine type and disk
Service accounts	Node SA (logging/monitoring) + Workload Identity SA (API)
IAM bindings	Workload Identity, Secret Manager access, BigQuery access (optional)

Prerequisites

Terraform 1.5+
gcloud CLI authenticated with a project
GCP project with billing enabled
Sufficient IAM permissions (Project Owner or Editor)

Quick Start with Setup Wizard

The included setup wizard handles Terraform state, cluster provisioning, and Helm deployment in one flow:

cd terraform
./setup.sh          # Full interactive setup
./setup.sh --dry-run  # Generate config files only
./setup.sh --resume   # Resume from Helm deploy

The wizard prompts for:

Cloud provider (GCP)
Secret namespace prefix
Secret provider (GCP Secret Manager or MongoDB)
GCP project ID, region, cluster name
Terraform state bucket (auto-creates if needed)
Machine type and node scaling
BigQuery IAM (optional)
SECRET_ENCRYPTION_KEY (auto-generates or user-provided)

After provisioning, it automatically:

Configures kubectl credentials
Creates the Kubernetes namespace and secrets
Deploys API and Dashboard via Helm
Waits for ingress and verifies health checks
Displays the dashboard URL

Manual Deployment

Step 1: Create a Terraform State Bucket

PROJECT_ID=$(gcloud config get-value project)
gsutil mb -p $PROJECT_ID gs://$PROJECT_ID-terraform-state
gsutil versioning set on gs://$PROJECT_ID-terraform-state

Step 2: Configure Variables

Create terraform/gcp/prod/terraform.tfvars:

project_id   = "my-gcp-project"
region       = "us-central1"
cluster_name = "decisionbox-prod"

# Networking
create_vpc  = true
subnet_cidr = "10.0.0.0/20"
pods_cidr   = "10.4.0.0/14"
services_cidr = "10.8.0.0/20"

# Node pool
machine_type   = "e2-standard-2"
min_node_count = 1
max_node_count = 2
disk_size_gb   = 50

# Workload Identity
k8s_namespace       = "decisionbox"
k8s_service_account = "decisionbox-api"

# Optional: GCP Secret Manager
enable_gcp_secrets = true
secret_namespace   = "decisionbox"

# Optional: BigQuery read access
enable_bigquery_iam = true

Step 3: Initialize and Apply

cd terraform/gcp/prod

terraform init \
  -backend-config="bucket=$PROJECT_ID-terraform-state" \
  -backend-config="prefix=prod"

terraform plan -out=tfplan
terraform apply tfplan

Step 4: Configure kubectl

gcloud container clusters get-credentials decisionbox-prod \
  --region us-central1 \
  --project $PROJECT_ID

Step 5: Deploy with Helm

Follow the Kubernetes Deployment guide to deploy the API and Dashboard.

When using GCP Secret Manager with Workload Identity, annotate the service account:

# values-prod.yaml
serviceAccountAnnotations:
  iam.gke.io/gcp-service-account: "decisionbox-prod-api@my-gcp-project.iam.gserviceaccount.com"

Module Architecture

terraform/gcp/
├── prod/
│   ├── versions.tf      # Provider versions (Google 5.0-7.0)
│   ├── variables.tf     # Environment-level variables
│   ├── main.tf          # Module instantiation
│   └── outputs.tf       # Cluster outputs
└── modules/decisionbox/
    ├── apis.tf           # GCP API enablement
    ├── networking.tf     # VPC, subnets, NAT, firewalls
    ├── gke.tf            # GKE cluster + node pool
    ├── iam.tf            # Service accounts + Workload Identity
    ├── secrets.tf        # Secret Manager IAM (conditional)
    ├── bigquery.tf       # BigQuery IAM (conditional)
    ├── variables.tf      # 40+ input variables
    └── outputs.tf        # Cluster outputs

Variables Reference

All variables are defined in terraform/gcp/modules/decisionbox/variables.tf.

Required

Variable	Type	Description
`project_id`	string	GCP project ID

Cluster

Variable	Type	Default	Description
`region`	string	`us-central1`	GCP region
`cluster_name`	string	`decisionbox-prod`	GKE cluster name
`create_cluster`	bool	`true`	Create GKE cluster (false to use existing)
`deletion_protection`	bool	`true`	Prevent accidental cluster deletion
`release_channel`	string	`REGULAR`	GKE release channel
`datapath_provider`	string	`ADVANCED_DATAPATH`	Dataplane V2 for network policy
`enable_network_policy`	bool	`true`	Enable network policy enforcement
`network_policy_provider`	string	`CALICO`	Network policy provider (used when not ADVANCED_DATAPATH)
`enable_binary_authorization`	bool	`false`	Binary Authorization for container images
`logging_components`	list(string)	`["SYSTEM_COMPONENTS", "WORKLOADS"]`	GKE logging components
`monitoring_components`	list(string)	`["SYSTEM_COMPONENTS"]`	GKE monitoring components

Networking

Variable	Type	Default	Description
`create_vpc`	bool	`true`	Create VPC (false to use existing)
`existing_vpc_id`	string	`""`	Existing VPC self-link (when `create_vpc=false`)
`existing_subnet_id`	string	`""`	Existing subnet self-link
`subnet_cidr`	string	`10.0.0.0/20`	Node subnet CIDR
`pods_cidr`	string	`10.4.0.0/14`	Pod IP range
`pods_range_name`	string	`pods`	Secondary range name for pods
`services_cidr`	string	`10.8.0.0/20`	Service IP range
`services_range_name`	string	`services`	Secondary range name for services
`master_cidr`	string	`172.16.0.0/28`	Control plane CIDR
`enable_private_nodes`	bool	`true`	Nodes have no public IPs
`enable_private_endpoint`	bool	`false`	Restrict master to private network
`master_authorized_networks`	list(object)	`[{cidr_block="0.0.0.0/0", display_name="all"}]`	CIDRs allowed to reach the master API
`enable_flow_logs`	bool	`true`	VPC flow logs
`flow_log_interval`	string	`INTERVAL_10_MIN`	Flow log aggregation interval
`flow_log_sampling`	number	`0.5`	Flow log sampling rate (0.0-1.0)
`flow_log_metadata`	string	`INCLUDE_ALL_METADATA`	Flow log metadata inclusion

NAT

Variable	Type	Default	Description
`nat_ip_allocate_option`	string	`AUTO_ONLY`	NAT IP allocation
`nat_source_subnetwork_ip_ranges`	string	`ALL_SUBNETWORKS_ALL_IP_RANGES`	NAT source ranges
`enable_nat_logging`	bool	`true`	Cloud NAT logging
`nat_log_filter`	string	`ERRORS_ONLY`	NAT log filter

Firewall

Variable	Type	Default	Description
`internal_tcp_ports`	list(string)	`["0-65535"]`	Internal TCP ports allowed
`internal_udp_ports`	list(string)	`["0-65535"]`	Internal UDP ports allowed
`health_check_ports`	list(string)	`["80","443","3000","8080","10256"]`	Health check ports
`health_check_source_ranges`	list(string)	`["35.191.0.0/16","130.211.0.0/22"]`	GCP health check IP ranges

Node Pool

Variable	Type	Default	Description
`machine_type`	string	`e2-standard-2`	GCE machine type
`disk_size_gb`	number	`50`	Boot disk size (GB)
`disk_type`	string	`pd-standard`	Boot disk type
`image_type`	string	`COS_CONTAINERD`	Node image
`min_node_count`	number	`1`	Minimum nodes per zone
`max_node_count`	number	`2`	Maximum nodes per zone
`enable_secure_boot`	bool	`true`	Shielded VM secure boot
`enable_integrity_monitoring`	bool	`true`	Shielded VM integrity monitoring
`enable_auto_repair`	bool	`true`	Auto-repair unhealthy nodes
`enable_auto_upgrade`	bool	`true`	Auto-upgrade node versions
`disable_legacy_metadata_endpoints`	string	`"true"`	Disable legacy metadata API

IAM & Secrets

Variable	Type	Default	Description
`k8s_namespace`	string	`decisionbox`	Kubernetes namespace for Workload Identity
`k8s_service_account`	string	`decisionbox-api`	K8s service account name (API)
`k8s_agent_service_account`	string	`decisionbox-agent`	K8s service account name (Agent, read-only)
`enable_gcp_secrets`	bool	`false`	Create Secret Manager IAM bindings
`secret_namespace`	string	`decisionbox`	Secret name prefix for IAM conditions
`enable_bigquery_iam`	bool	`false`	Grant BigQuery read access to the agent SA

Labels

Variable	Type	Default	Description
`labels`	map(string)	`{}`	Resource labels applied to all resources

Outputs

Output	Sensitive	Description
`cluster_name`	No	GKE cluster name
`cluster_endpoint`	Yes	Kubernetes API endpoint
`cluster_ca_certificate`	Yes	CA certificate for kubectl
`vpc_name`	No	VPC network name
`workload_identity_sa_email`	No	GCP service account for API Workload Identity
`agent_workload_identity_sa_email`	No	GCP service account for Agent Workload Identity (read-only)
`gcp_secrets_iam_enabled`	No	Whether Secret Manager IAM was configured
`bigquery_iam_enabled`	No	Whether BigQuery IAM was configured

Workload Identity

The module creates a GCP service account and binds it to a Kubernetes service account via Workload Identity. This allows the API pod to authenticate to GCP services (Secret Manager, BigQuery) without storing credentials.

K8s ServiceAccount: decisionbox/decisionbox-api
    ↕ Workload Identity binding
GCP ServiceAccount: decisionbox-prod-api@project.iam.gserviceaccount.com
    ↓ IAM roles
GCP Secret Manager (namespace-scoped)
BigQuery (data viewer + job user)

The Helm chart must annotate the K8s service account:

serviceAccountAnnotations:
  iam.gke.io/gcp-service-account: "decisionbox-prod-api@my-project.iam.gserviceaccount.com"

Secret Manager Scoping

When enable_gcp_secrets=true, the module creates IAM bindings with conditions that restrict the API to secrets prefixed with the configured namespace:

Allowed: decisionbox-project123-llm-api-key
Blocked: other-app-database-password

This ensures multi-tenant isolation when multiple applications share a GCP project.

Using an Existing VPC

To deploy into an existing network:

create_vpc         = false
existing_vpc_id    = "projects/my-project/global/networks/my-vpc"
existing_subnet_id = "projects/my-project/regions/us-central1/subnetworks/my-subnet"

The subnet must have secondary IP ranges named pods and services.

Destroying Resources

# Remove Helm releases first
helm uninstall decisionbox-dashboard -n decisionbox
helm uninstall decisionbox-api -n decisionbox

# Disable deletion protection
terraform apply -var="deletion_protection=false"

# Destroy infrastructure
terraform destroy

Next Steps

Kubernetes Deployment — Deploy with Helm after Terraform
Helm Values Reference — All chart configuration options
Production Considerations — Scaling, monitoring, backups

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Terraform — GCP

What It Creates

Prerequisites

Quick Start with Setup Wizard

Manual Deployment

Step 1: Create a Terraform State Bucket

Step 2: Configure Variables

Step 3: Initialize and Apply

Step 4: Configure kubectl

Step 5: Deploy with Helm

Module Architecture

Variables Reference

Required

Cluster

Networking

NAT

Firewall

Node Pool

IAM & Secrets

Labels

Outputs

Workload Identity

Secret Manager Scoping

Using an Existing VPC

Destroying Resources

Next Steps

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Terraform — GCP

What It Creates

Prerequisites

Quick Start with Setup Wizard

Manual Deployment

Step 1: Create a Terraform State Bucket

Step 2: Configure Variables

Step 3: Initialize and Apply

Step 4: Configure kubectl

Step 5: Deploy with Helm

Module Architecture

Variables Reference

Required

Cluster

Networking

NAT

Firewall

Node Pool

IAM & Secrets

Labels

Outputs

Workload Identity

Secret Manager Scoping

Using an Existing VPC

Destroying Resources

Next Steps