Custom VPC creation in GCP - Mini Project: Build & Apply

Custom VPC creation

📖 Scenario: You are setting up a new Google Cloud environment for a small company. They want a custom Virtual Private Cloud (VPC) network to control their cloud resources and traffic.

🎯 Goal: Create a custom VPC network with one subnet in a specific region. This network will be the foundation for deploying cloud resources securely.

📋 What You'll Learn

Create a custom VPC network named custom-vpc

Add a subnet named custom-subnet in the us-central1 region

Set the subnet IP range to 10.0.0.0/24

Ensure the VPC is set to custom subnet mode

💡 Why This Matters

🌍 Real World

Custom VPCs let companies control their cloud network layout, improving security and traffic management.

💼 Career

Cloud engineers often create and manage VPCs to isolate resources and meet organizational policies.

1

Create a custom VPC network

Create a variable called network_name and set it to the string custom-vpc.

GCP

# Create a variable called network_name and set it to 'custom-vpc'
# Your code here

Hint

Use quotes around the network name string.

2

Define the subnet configuration

Create a dictionary called subnet_config with keys name, region, and ip_cidr_range. Set their values to custom-subnet, us-central1, and 10.0.0.0/24 respectively.

GCP

network_name = "custom-vpc"
# Create a dictionary called subnet_config with the specified keys and values
# Your code here

Hint

Use curly braces to create the dictionary and separate keys and values with colons.

3

Create the VPC network configuration

Create a dictionary called vpc_config with keys name, auto_create_subnetworks, and subnetworks. Set name to network_name, auto_create_subnetworks to False, and subnetworks to a list containing subnet_config.

GCP

network_name = "custom-vpc"
subnet_config = {
    "name": "custom-subnet",
    "region": "us-central1",
    "ip_cidr_range": "10.0.0.0/24"
}
# Create a dictionary called vpc_config with the specified keys and values
# Your code here

Hint

Remember to use the variable network_name for the name key and put subnet_config inside a list for subnetworks.

4

Add the final VPC creation command

Create a dictionary called create_vpc_request with a single key network set to vpc_config.

GCP

network_name = "custom-vpc"
subnet_config = {
    "name": "custom-subnet",
    "region": "us-central1",
    "ip_cidr_range": "10.0.0.0/24"
}
vpc_config = {
    "name": network_name,
    "auto_create_subnetworks": False,
    "subnetworks": [subnet_config]
}
# Create a dictionary called create_vpc_request with key 'network' set to vpc_config
# Your code here

Hint

This dictionary represents the final request to create the VPC network.

Practice

1. What is the main advantage of creating a Custom VPC in Google Cloud Platform?

easy

A. You can define your own IP address ranges and subnets.

B. It automatically creates default firewall rules.

C. It provides free internet access without configuration.

D. It disables all network traffic by default.

Solution

1. Step 1: Understand Custom VPC purpose

   A Custom VPC allows you to design your network with your own IP ranges and subnets, unlike default VPCs which have preset ranges.

2. Step 2: Eliminate wrong options

   Custom VPC does not disable traffic, default firewall rules exist regardless, free internet requires configuration.

3. Final Answer:

   You can define your own IP address ranges and subnets. -> Option A

4. Quick Check:

   Custom VPC = Custom IP ranges [OK]

Hint: Custom VPC means you pick your IP ranges [OK]

Common Mistakes:

• Confusing default VPC with custom VPC
• Thinking firewall rules are auto-created
• Assuming internet access is automatic

2. Which gcloud command correctly creates a custom VPC named my-vpc with no automatic subnet creation?

easy

A. gcloud compute networks create my-vpc --subnet-mode=auto

B. gcloud compute networks create my-vpc --auto-create-subnetworks

C. gcloud compute networks create my-vpc --no-subnet-mode

D. gcloud compute networks create my-vpc --subnet-mode=custom

Solution

1. Step 1: Identify subnet mode for custom VPC

   Custom VPC requires the flag --subnet-mode=custom to avoid automatic subnet creation.

2. Step 2: Evaluate options

   --subnet-mode=auto creates automatic subnets. --auto-create-subnetworks uses invalid syntax. --no-subnet-mode does not exist.

3. Final Answer:

   gcloud compute networks create my-vpc --subnet-mode=custom -> Option D

4. Quick Check:

   Custom VPC uses --subnet-mode=custom [OK]

Hint: Use --subnet-mode=custom to create custom VPC [OK]

Common Mistakes:

• Using --subnet-mode=auto instead of custom
• Using invalid flags like --no-subnet-mode
• Assuming subnets are created automatically

3. Given this command:

gcloud compute networks subnets create subnet-1 --network=my-vpc --region=us-central1 --range=10.0.1.0/24

What is the CIDR range assigned to subnet-1?

medium

A. 10.0.0.0/16

B. 192.168.1.0/24

C. 10.0.1.0/24

D. 10.1.0.0/24

Solution

1. Step 1: Read the subnet creation command

   The command specifies --range=10.0.1.0/24 which sets the IP range for the subnet.

2. Step 2: Match the CIDR range

   10.0.1.0/24 matches the exact CIDR range given in the command.

3. Final Answer:

   10.0.1.0/24 -> Option C

4. Quick Check:

   Subnet range = 10.0.1.0/24 [OK]

Hint: Look for --range flag for subnet CIDR [OK]

Common Mistakes:

• Confusing VPC range with subnet range
• Picking wrong CIDR block from options
• Ignoring the --range parameter

4. You ran this command to create a subnet:

gcloud compute networks subnets create subnet-2 --network=my-vpc --region=us-east1 --range=10.0.1.0/24

But you get an error saying the IP range overlaps with an existing subnet. What is the likely cause?

medium

A. The subnet range 10.0.1.0/24 overlaps with another subnet in the same VPC.

B. The region us-east1 is invalid for subnet creation.

C. The network my-vpc does not exist.

D. The command is missing the --subnet-mode flag.

Solution

1. Step 1: Understand the error message

   The error about overlapping IP range means the subnet's CIDR block conflicts with an existing subnet in the same VPC.

2. Step 2: Check other options

   Region and network existence errors produce different messages; --subnet-mode is for network creation, not subnet.

3. Final Answer:

   The subnet range 10.0.1.0/24 overlaps with another subnet in the same VPC. -> Option A

4. Quick Check:

   Overlapping CIDR causes subnet creation error [OK]

Hint: Check subnet CIDR overlaps before creating [OK]

Common Mistakes:

• Assuming region is invalid without checking
• Confusing network creation flags with subnet flags
• Ignoring existing subnet CIDR ranges

5. You want to create a custom VPC named prod-vpc with two subnets:
- subnet-a in us-west1 with range 10.10.1.0/24
- subnet-b in us-east1 with range 10.10.2.0/24
Which sequence of gcloud commands correctly creates this setup?

hard

A. 1) gcloud compute networks create prod-vpc --subnet-mode=auto
2) gcloud compute networks subnets create subnet-a --network=prod-vpc --region=us-west1 --range=10.10.1.0/24
3) gcloud compute networks subnets create subnet-b --network=prod-vpc --region=us-east1 --range=10.10.2.0/24

B. 1) gcloud compute networks create prod-vpc --subnet-mode=custom
2) gcloud compute networks subnets create subnet-a --network=prod-vpc --region=us-west1 --range=10.10.1.0/24
3) gcloud compute networks subnets create subnet-b --network=prod-vpc --region=us-east1 --range=10.10.2.0/24

C. 1) gcloud compute networks create prod-vpc
2) gcloud compute networks subnets create subnet-a --network=prod-vpc --region=us-west1 --range=10.10.1.0/24
3) gcloud compute networks subnets create subnet-b --network=prod-vpc --region=us-east1 --range=10.10.2.0/24

D. 1) gcloud compute networks create prod-vpc --subnet-mode=custom
2) gcloud compute networks subnets create subnet-a --network=prod-vpc --region=us-west1 --range=10.10.2.0/24
3) gcloud compute networks subnets create subnet-b --network=prod-vpc --region=us-east1 --range=10.10.1.0/24

Solution

1. Step 1: Create the VPC with custom subnet mode

   The VPC must be created with --subnet-mode=custom to allow manual subnet creation.

2. Step 2: Create subnets with correct regions and CIDR ranges

   Subnets must be created with specified regions and matching CIDR ranges as per requirements.

3. Step 3: Verify order and correctness

   1) gcloud compute networks create prod-vpc --subnet-mode=custom 2) gcloud compute networks subnets create subnet-a --network=prod-vpc --region=us-west1 --range=10.10.1.0/24 3) gcloud compute networks subnets create subnet-b --network=prod-vpc --region=us-east1 --range=10.10.2.0/24 correctly creates the VPC first, then subnets with correct ranges and regions. 1) gcloud compute networks create prod-vpc --subnet-mode=auto 2) gcloud compute networks subnets create subnet-a --network=prod-vpc --region=us-west1 --range=10.10.1.0/24 3) gcloud compute networks subnets create subnet-b --network=prod-vpc --region=us-east1 --range=10.10.2.0/24 uses auto subnet mode which auto-creates subnets, conflicting with manual subnet creation. 1) gcloud compute networks create prod-vpc 2) gcloud compute networks subnets create subnet-a --network=prod-vpc --region=us-west1 --range=10.10.1.0/24 3) gcloud compute networks subnets create subnet-b --network=prod-vpc --region=us-east1 --range=10.10.2.0/24 misses subnet mode flag. 1) gcloud compute networks create prod-vpc --subnet-mode=custom 2) gcloud compute networks subnets create subnet-a --network=prod-vpc --region=us-west1 --range=10.10.2.0/24 3) gcloud compute networks subnets create subnet-b --network=prod-vpc --region=us-east1 --range=10.10.1.0/24 swaps CIDR ranges between subnets.

4. Final Answer:

   Correct sequence with custom subnet mode and matching subnet ranges -> Option B

5. Quick Check:

   Custom VPC + correct subnet ranges = 1) gcloud compute networks create prod-vpc --subnet-mode=custom 2) gcloud compute networks subnets create subnet-a --network=prod-vpc --region=us-west1 --range=10.10.1.0/24 3) gcloud compute networks subnets create subnet-b --network=prod-vpc --region=us-east1 --range=10.10.2.0/24 [OK]

Hint: Create VPC with --subnet-mode=custom before adding subnets [OK]

Common Mistakes:

• Using auto subnet mode when manual subnets needed
• Swapping subnet CIDR ranges by mistake
• Omitting --subnet-mode flag on VPC creation