In today’s multi-cloud world, ensuring seamless connectivity between different cloud environments is crucial for businesses looking to leverage the best features of each platform. Establishing a VPN connection between Google Cloud Platform (GCP) and Amazon Web Services (AWS) allows for secure and efficient cross-cloud communication. This guide will walk you through setting up a classic VPN with static routing between GCP and AWS.

Introduction: The Need for Cross-Cloud Connectivity

As organizations increasingly adopt multi-cloud strategies, robust cross-cloud connectivity becomes paramount. By establishing a VPN between GCP and AWS, businesses can securely transmit data, synchronize workloads, and maintain high availability across cloud platforms. This guide provides a comprehensive, step-by-step approach to setting up a static routing VPN between GCP and AWS, ensuring your environments are securely and efficiently connected.

Preparing the GCP Environment

Creating the GCP Virtual Private Cloud (VPC)

  1. Access the GCP Console: Navigate to the VPC network section.
  2. Create a New VPC: Define the network’s name, region, and CIDR range. Ensure that the CIDR range does not overlap with the AWS VPC CIDR.
  3. Subnets Configuration: Configure subnets within the VPC as required by your application needs.

Reserving a Static IP Address in GCP

  1. Navigate to External IP Addresses: Reserve a new static IP under the relevant region.
  2. Assign a Name: Clearly label the IP address to differentiate it from other resources.
  3. Allocate the IP: Ensure the IP is tied to the VPC you’ve created for the VPN setup.

Configuring AWS

Setting up the AWS VPC and Subnet

  1. Access the AWS Management Console: Navigate to the VPC dashboard.
  2. Create a New VPC: Specify the CIDR block, ensuring it does not overlap with the GCP VPC.
  3. Configure Subnets: Create subnets within the VPC, keeping your architecture requirements in mind.

Representing GCP: Creating the Customer Gateway

  1. Create a Customer Gateway: Provide the static IP reserved in GCP.
  2. Define the BGP ASN: Use your network’s appropriate Autonomous System Number (ASN).

Bridging the Clouds: Establishing the Virtual Private Gateway

  1. Create a Virtual Private Gateway (VGW): Attach it to the AWS VPC.
  2. Associate the VGW: Link the Virtual Private Gateway to the Customer Gateway representing GCP.

Initiating the VPN Connection and Downloading Configurations

  1. Create the VPN Connection: Select static routing and input the necessary routing details.
  2. Download Configuration Files: Obtain the VPN configuration file to import into GCP.

Returning to GCP

Importing AWS Configurations

  1. Navigate to the GCP VPN Section: Start the process to create a new VPN gateway.
  2. Import Configuration: Use the details from the AWS VPN configuration file.

Establishing the Google Compute Engine VPN Gateway

  1. Create a New VPN Gateway: Use the static IP address reserved earlier.
  2. Configure the Tunnel: Input the shared secret, IKE version, and routing details.

Configuring Tunnel Details and Routing

  1. Define Static Routes: Specify the AWS VPC CIDR block and the next hop as the AWS VPN endpoint.
  2. Implement Routing Rules: Ensure routes are correctly configured to direct traffic through the VPN tunnel.

Implementing Firewall Rules for Secure Access

  1. Create Firewall Rules: Allow traffic from the AWS VPC CIDR to the GCP VPC CIDR.
  2. Restrict Access: Only permit necessary traffic types and ports to minimize security risks.

Finalizing AWS Configurations

Creating and Attaching the Internet Gateway

  1. Create an Internet Gateway (IGW): Attach it to the AWS VPC.
  2. Update Route Tables: Direct all outbound traffic through the Internet Gateway.

Enabling Route Propagation for Seamless Communication

  1. Configure Route Tables: Ensure that routes to the GCP VPC are propagated automatically via the VGW.
  2. Enable Propagation: Apply the necessary settings to allow route propagation.

Creating an EC2 Instance and Configuring Security Groups

  1. Launch an EC2 Instance: Ensure it’s within the same subnet as the VGW.
  2. Configure Security Groups: Permit inbound and outbound traffic to and from the GCP VPC CIDR.

Validating Connectivity

Creating a GCP Virtual Machine (VM)

  1. Launch a VM in GCP: Place it within the subnet of the configured GCP VPC.
  2. Configure VM: Ensure it can communicate with AWS resources over the necessary ports.

Testing Connectivity with Ping

  1. Ping from GCP VM to AWS EC2: Verify that the packets successfully traverse the VPN.
  2. Ping from AWS EC2 to GCP VM: Confirm the bidirectional traffic flow.

Conclusion

Following this guide, you’ve successfully established a secure, static routing VPN connection between GCP and AWS, allowing seamless cross-cloud communication. This setup is critical for multi-cloud architectures where integrating services across platforms is essential for business continuity and scalability.

References

Edit static routes for a Site-to-Site VPN connection

Configuration of a dynamic routing based Site-to-Site VPN between AWS Cloud and Google Cloud Platform