A Virtual Private Cloud (VPC) in Google Cloud is a global, private network that provides networking functionality for your cloud resources. Creating a VPC with subnets is fundamental to deploying any cloud solution.
When creating a VPC, you have two modes: auto mode and custom mode. Auto mode VPCs…A Virtual Private Cloud (VPC) in Google Cloud is a global, private network that provides networking functionality for your cloud resources. Creating a VPC with subnets is fundamental to deploying any cloud solution.
When creating a VPC, you have two modes: auto mode and custom mode. Auto mode VPCs automatically create one subnet in each Google Cloud region with predefined IP ranges. Custom mode VPCs give you complete control over subnet creation and IP addressing.
To create a custom VPC with subnets, follow these steps:
1. Navigate to VPC Networks in the Google Cloud Console or use gcloud commands.
2. Create the VPC network specifying custom subnet mode:
gcloud compute networks create my-vpc --subnet-mode=custom
3. Create subnets within the VPC, specifying region and IP range:
gcloud compute networks subnets create my-subnet --network=my-vpc --region=us-central1 --range=10.0.1.0/24
Key considerations when planning subnets:
- IP Range Planning: Choose non-overlapping CIDR ranges. Consider future growth and avoid conflicts with on-premises networks if hybrid connectivity is needed.
- Regional Placement: Subnets are regional resources. Place them in regions close to your users or where your resources will be deployed.
- Secondary Ranges: You can add secondary IP ranges for alias IPs, useful for container networking.
- Private Google Access: Enable this to allow instances with only internal IPs to reach Google APIs and services.
- Flow Logs: Enable VPC Flow Logs for network monitoring and analysis.
Best practices include using meaningful naming conventions, documenting IP allocations, and planning for scalability. Remember that subnet IP ranges can be expanded but not shrunk after creation.
Firewall rules control traffic flow within your VPC and should be configured alongside subnet creation to ensure proper security posture for your cloud solution.
Creating a VPC with Subnets - Complete Guide for GCP Associate Cloud Engineer
Why is Creating a VPC with Subnets Important?
Virtual Private Cloud (VPC) networks are the foundation of your cloud infrastructure in Google Cloud Platform. Understanding how to create VPCs with subnets is essential because it determines how your resources communicate, how traffic flows, and how security is implemented. This knowledge is fundamental for the Associate Cloud Engineer exam and real-world cloud deployments.
What is a VPC with Subnets?
A VPC (Virtual Private Cloud) is a global, private network that spans all GCP regions. It provides networking functionality for your cloud resources like Compute Engine instances, Kubernetes clusters, and Cloud Functions.
A Subnet is a regional resource that defines a range of IP addresses within a VPC. Each subnet is associated with a specific region and has a primary IP range in CIDR notation.
Key characteristics: - VPCs are global resources - Subnets are regional resources - Subnets cannot span multiple regions - Resources in different subnets can communicate using internal IP addresses
How VPC and Subnet Creation Works
VPC Network Modes:
1. Auto Mode VPC: - Automatically creates one subnet in each GCP region - Uses predefined IP ranges (10.128.0.0/9) - Easy to set up but less flexible - Subnets are automatically added when new regions become available
2. Custom Mode VPC: - No subnets are created automatically - You define subnets manually with custom IP ranges - Provides full control over IP addressing - Recommended for production environments
Creating a VPC via Console: - Navigate to VPC Network in the console - Click Create VPC Network - Choose auto or custom mode - Define subnet name, region, and IP range - Configure firewall rules as needed
- Primary IP Range: The main CIDR range for a subnet - Secondary IP Ranges: Additional ranges for alias IPs, used with GKE pods and services - Private Google Access: Allows VMs with only internal IPs to reach Google APIs - Flow Logs: Capture network traffic metadata for monitoring - Firewall Rules: Applied at the VPC level, not subnet level
Exam Tips: Answering Questions on Creating a VPC with Subnets
1. Know the difference between Auto and Custom mode: If a question asks about production environments or specific IP requirements, Custom mode is typically the answer.
2. Remember subnet scope: When asked about resource placement, recall that subnets are regional. A subnet in us-central1 cannot host resources in europe-west1.
3. IP Range Planning: Ensure CIDR ranges do not overlap, especially when VPC peering is involved. Questions often test this knowledge.
4. Watch for Private Google Access: If a question involves VMs reaching Google APIs using only internal IPs, Private Google Access must be enabled on the subnet.
5. Firewall rule scope: Remember that firewall rules are VPC-level resources, not subnet-specific. They apply based on tags, service accounts, or IP ranges.
6. Converting Auto to Custom: You can convert an auto mode VPC to custom mode, but you cannot convert custom back to auto. This is a common exam topic.
7. Shared VPC considerations: Questions about multi-project networking often involve Shared VPC, where subnets from a host project are shared with service projects.
8. CIDR notation mastery: Understand that /16 provides more addresses than /24. Smaller CIDR numbers mean larger networks.
9. Default VPC: GCP projects come with a default auto mode VPC. Questions may ask about modifying or replacing it.
10. Read questions carefully: Look for keywords like 'least privilege', 'cost-effective', or 'minimal configuration' to guide your answer toward the appropriate VPC design.