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From oraclecloud-pack
Deploys production-ready 3-tier OCI architecture with VCN, subnets, gateways, load balancer, compute, and Autonomous DB via Terraform.
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/oraclecloud-pack:oraclecloud-reference-architectureThis skill is limited to the following tools:
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OCI architecture has more moving parts than AWS or Azure. Where AWS has VPC + subnets + internet gateway, OCI has VCN + regional subnets + Internet Gateway + NAT Gateway + Service Gateway + DRG (Dynamic Routing Gateway) + LPG (Local Peering Gateway) — and getting the routing tables wrong means silent packet drops with no error. This provides the standard 3-tier architecture (web/app/db) with ev...
OCI architecture has more moving parts than AWS or Azure. Where AWS has VPC + subnets + internet gateway, OCI has VCN + regional subnets + Internet Gateway + NAT Gateway + Service Gateway + DRG (Dynamic Routing Gateway) + LPG (Local Peering Gateway) — and getting the routing tables wrong means silent packet drops with no error. This provides the standard 3-tier architecture (web/app/db) with every OCI-specific component wired correctly, plus Terraform code to deploy it.
Purpose: Produce a production-ready 3-tier OCI architecture with correctly configured networking, gateways, security rules, and compute/database tiers — deployable via Terraform.
~/.oci/config validated (see oraclecloud-install-auth)pip install oci┌─────────────────────────── OCI Region (us-ashburn-1) ───────────────────────────┐
│ │
│ ┌────────────────────────── VCN (10.0.0.0/16) ──────────────────────────────┐ │
│ │ │ │
│ │ ┌─── Internet GW ───┐ ┌─── NAT GW ───┐ ┌─── Service GW ───┐ │ │
│ │ └────────┬───────────┘ └──────┬────────┘ └───────┬──────────┘ │ │
│ │ │ │ │ │ │
│ │ ┌────────▼──────────────────────────────────────────────────────────┐ │ │
│ │ │ Public Subnet (10.0.1.0/24) — Web Tier │ │ │
│ │ │ Load Balancer (public) → routes to App Tier │ │ │
│ │ │ Bastion Host (optional) │ │ │
│ │ └──────────────────────┬───────────────────────────────────────────┘ │ │
│ │ │ │ │
│ │ ┌──────────────────────▼───────────────────────────────────────────┐ │ │
│ │ │ Private Subnet (10.0.2.0/24) — App Tier │ │ │
│ │ │ Compute Instances (VM.Standard.E4.Flex) │ │ │
│ │ │ → NAT GW for outbound internet (patching, APIs) │ │ │
│ │ │ → Service GW for OCI services (Object Storage, etc.) │ │ │
│ │ └──────────────────────┬───────────────────────────────────────────┘ │ │
│ │ │ │ │
│ │ ┌──────────────────────▼───────────────────────────────────────────┐ │ │
│ │ │ Private Subnet (10.0.3.0/24) — DB Tier │ │ │
│ │ │ Autonomous Database (ATP or ADW) │ │ │
│ │ │ → Service GW only (no internet access) │ │ │
│ │ └──────────────────────────────────────────────────────────────────┘ │ │
│ │ │ │
│ │ ┌─── DRG ───┐ ← On-premises or cross-region peering │ │
│ │ └────────────┘ │ │
│ └────────────────────────────────────────────────────────────────────────────┘ │
└──────────────────────────────────────────────────────────────────────────────────┘
| Gateway | Purpose | Attached To | Use Case |
|---|---|---|---|
| Internet Gateway | Bidirectional internet access | Public subnet route table | Load balancers, bastion hosts |
| NAT Gateway | Outbound-only internet access | Private subnet route table | App servers needing patches, external APIs |
| Service Gateway | Access OCI services without internet | Private subnet route table | Object Storage, Autonomous DB, OCI APIs |
| DRG (Dynamic Routing Gateway) | On-premises / cross-region connectivity | VCN attachment | VPN, FastConnect, inter-region peering |
| LPG (Local Peering Gateway) | VCN-to-VCN within same region | VCN attachment | Shared services VCN, hub-spoke topology |
import oci
config = oci.config.from_file("~/.oci/config")
network = oci.core.VirtualNetworkClient(config)
# Create VCN
vcn = network.create_vcn(
oci.core.models.CreateVcnDetails(
compartment_id="COMPARTMENT_OCID",
display_name="prod-vcn",
cidr_blocks=["10.0.0.0/16"],
dns_label="prodvcn",
)
).data
print(f"VCN created: {vcn.id}")
# Create public subnet (web tier)
web_subnet = network.create_subnet(
oci.core.models.CreateSubnetDetails(
compartment_id="COMPARTMENT_OCID",
vcn_id=vcn.id,
display_name="web-subnet-public",
cidr_block="10.0.1.0/24",
dns_label="web",
prohibit_internet_ingress=False, # Public subnet
)
).data
# Create private subnet (app tier)
app_subnet = network.create_subnet(
oci.core.models.CreateSubnetDetails(
compartment_id="COMPARTMENT_OCID",
vcn_id=vcn.id,
display_name="app-subnet-private",
cidr_block="10.0.2.0/24",
dns_label="app",
prohibit_internet_ingress=True, # Private subnet
)
).data
# Create private subnet (db tier)
db_subnet = network.create_subnet(
oci.core.models.CreateSubnetDetails(
compartment_id="COMPARTMENT_OCID",
vcn_id=vcn.id,
display_name="db-subnet-private",
cidr_block="10.0.3.0/24",
dns_label="db",
prohibit_internet_ingress=True, # Private subnet
)
).data
print(f"Subnets: web={web_subnet.id}, app={app_subnet.id}, db={db_subnet.id}")
# Internet Gateway (for web tier)
igw = network.create_internet_gateway(
oci.core.models.CreateInternetGatewayDetails(
compartment_id="COMPARTMENT_OCID",
vcn_id=vcn.id,
display_name="prod-igw",
is_enabled=True,
)
).data
# NAT Gateway (for app tier outbound)
nat = network.create_nat_gateway(
oci.core.models.CreateNatGatewayDetails(
compartment_id="COMPARTMENT_OCID",
vcn_id=vcn.id,
display_name="prod-nat",
)
).data
# Service Gateway (for db tier → OCI services)
services = network.list_services().data
all_services = next(s for s in services if "All" in s.name)
sgw = network.create_service_gateway(
oci.core.models.CreateServiceGatewayDetails(
compartment_id="COMPARTMENT_OCID",
vcn_id=vcn.id,
display_name="prod-sgw",
services=[oci.core.models.ServiceIdRequestDetails(service_id=all_services.id)],
)
).data
print(f"Gateways: igw={igw.id}, nat={nat.id}, sgw={sgw.id}")
# provider.tf
terraform {
required_providers {
oci = {
source = "oracle/oci"
version = ">= 5.0"
}
}
}
provider "oci" {
config_file_profile = "DEFAULT"
}
# vcn.tf
resource "oci_core_vcn" "prod" {
compartment_id = var.compartment_id
display_name = "prod-vcn"
cidr_blocks = ["10.0.0.0/16"]
dns_label = "prodvcn"
}
resource "oci_core_internet_gateway" "prod" {
compartment_id = var.compartment_id
vcn_id = oci_core_vcn.prod.id
display_name = "prod-igw"
enabled = true
}
resource "oci_core_nat_gateway" "prod" {
compartment_id = var.compartment_id
vcn_id = oci_core_vcn.prod.id
display_name = "prod-nat"
}
resource "oci_core_subnet" "web" {
compartment_id = var.compartment_id
vcn_id = oci_core_vcn.prod.id
display_name = "web-subnet-public"
cidr_block = "10.0.1.0/24"
dns_label = "web"
prohibit_internet_ingress = false
route_table_id = oci_core_route_table.public.id
security_list_ids = [oci_core_security_list.web.id]
}
resource "oci_core_subnet" "app" {
compartment_id = var.compartment_id
vcn_id = oci_core_vcn.prod.id
display_name = "app-subnet-private"
cidr_block = "10.0.2.0/24"
dns_label = "app"
prohibit_internet_ingress = true
route_table_id = oci_core_route_table.private.id
security_list_ids = [oci_core_security_list.app.id]
}
resource "oci_core_route_table" "public" {
compartment_id = var.compartment_id
vcn_id = oci_core_vcn.prod.id
display_name = "public-rt"
route_rules {
destination = "0.0.0.0/0"
network_entity_id = oci_core_internet_gateway.prod.id
}
}
resource "oci_core_route_table" "private" {
compartment_id = var.compartment_id
vcn_id = oci_core_vcn.prod.id
display_name = "private-rt"
route_rules {
destination = "0.0.0.0/0"
network_entity_id = oci_core_nat_gateway.prod.id
}
}
| Concept | AWS | Azure | OCI |
|---|---|---|---|
| Virtual network | VPC | VNet | VCN |
| Subnet | Subnet (AZ-scoped) | Subnet | Subnet (regional) |
| Internet access | Internet Gateway | — (default) | Internet Gateway |
| Outbound only | NAT Gateway | NAT Gateway | NAT Gateway |
| Private service access | VPC Endpoint | Private Endpoint | Service Gateway |
| Cross-network peering | VPC Peering | VNet Peering | LPG / DRG |
| Firewall rules | Security Group | NSG | NSG + Security List |
| Load balancer | ALB/NLB | Azure LB | OCI Load Balancer |
| Managed database | RDS/Aurora | Azure SQL | Autonomous Database |
Successful completion produces:
terraform plan && terraform apply| Error | Code | Cause | Solution |
|---|---|---|---|
| NotAuthorizedOrNotFound | 404 | Missing IAM policy for VCN creation | Add allow group netadmins to manage virtual-network-family in compartment prod |
| InvalidParameter | 400 | Overlapping CIDR blocks | Ensure VCN CIDR does not overlap with existing VCNs or on-premises networks |
| LimitExceeded | 400 | Hit VCN or subnet service limit | Request limit increase via Console > Governance > Service Limits |
| TooManyRequests | 429 | Rate limited during bulk creation | Add 2-second delays between resource creation calls |
| InternalError | 500 | OCI service issue during provisioning | Retry after 60 seconds; check https://ocistatus.oraclecloud.com |
| Terraform provider crash | — | OCI provider version incompatibility | Pin provider: version = "~> 5.0" (see oraclecloud-upgrade-migration) |
Quick VCN validation (CLI):
# List VCNs in a compartment
oci network vcn list \
--compartment-id "$COMPARTMENT_OCID" \
--query 'data[].{name:"display-name", cidr:"cidr-blocks", state:"lifecycle-state"}' \
--output table
# List subnets in a VCN
oci network subnet list \
--compartment-id "$COMPARTMENT_OCID" \
--vcn-id "$VCN_OCID" \
--query 'data[].{name:"display-name", cidr:"cidr-block", public:"prohibit-internet-ingress"}' \
--output table
Validate route table connectivity:
# Verify public subnet routes to Internet Gateway
oci network route-table get --rt-id "$PUBLIC_RT_OCID" \
--query 'data."route-rules"[].{dest:destination, target:"network-entity-id"}' \
--output table
After deploying the architecture, run oraclecloud-prod-checklist to validate production readiness, or see oraclecloud-migration-deep-dive for translating existing AWS/Azure workloads into this architecture pattern.
npx claudepluginhub jeremylongshore/claude-code-plugins-plus-skills --plugin oraclecloud-packProvides expert guidance on Oracle Cloud Infrastructure services, architecture patterns, cost optimization, and deployment strategies for building scalable, secure, and cost-effective solutions.
Builds OCI VCN networking from scratch with subnets, gateways, route tables, and security rules using Python SDK. For new VCNs, connectivity issues, or security lists/NSGs.
Design, review, and troubleshoot OCI VCNs, subnets, route tables, DRGs, gateways, peering, security lists, NSGs, load balancers, DNS, and connectivity.