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Connect Google Cloud Platform (GCP) to HCP via AWS Transit Gateway

  • 13min
  • |
  • HCP
  • Vault

The HashiCorp Cloud Platform (HCP) supports native connectivity solutions with multiple public cloud providers. Through the supported cloud providers, customers can enable common hybrid cloud networking models to support workloads with providers not yet natively supported by HCP using a concept known as a transit network.

A transit network acts as a bridge between multiple networks. Commonly, this may be used to connect different VLAN or VXLAN networks.

diagram-conceptual-transit-network

When running workloads in multiple public cloud providers, you can extend this model by connecting the public cloud providers through their supported networking services.

Compute resources running in the Google Cloud Platform can access private HCP resources such as an HCP Vault cluster by creating a VPN between GCP and a transit AWS VPC, then connecting the HCP HashiCorp Virtual Network (HVN) with the transit AWS VPC and configuring the necessary routing to direct traffic between the networks.

diagram-hcp-aws-gcp-transit-network

In this tutorial, you will create a Virtual Private Network (VPN) between AWS and GCP, create a transit gateway connection between HCP and AWS, and configure routing between each of the three platforms. When the network connectivity is complete, you will deploy a private instance of HCP Vault and access it from a GCP VM instance.

To avoid skipping important topics, the majority of this tutorial is guided through user interface (UI) of AWS, GCP, and HCP.

Note

It is recommended to follow this tutorial using test accounts for GCP, AWS, and HCP. Changes will be made that may impact connectivity of existing services. Be sure to validate the configuration changes in this tutorial will be supported in a production environment.

Prerequisites

  • An AWS and GCP account with the default configurations
  • An HCP Account
  • Non-overlapping network CIDR ranges for HCP HVN, AWS and GCP VPCs.
  • An HCP user assigned the contributor role (or higher) to perform the following actions:
    • Create an HVN, HCP Vault cluster, transit gateway attachment
    • Update the HVN route table
  • AWS permissions to perform the following actions:
    • Create a transit gateway, customer gateway, site to site VPN, and shared shared resource access manager
    • Accept a transit gateway connections
  • GCP permissions to perform the following actions
    • Create a cloud router, VPN, and VM instance

Create GCP VPN

You will start the configuration of the GCP side of the VPN tunnel. When you have enough information from the GCP side you will then configure the AWS side of the VPN before switching back to complete the setup in GCP.

  1. Open a web browser and log into your GCP account.

  2. From the Google Cloud console click the hamburger menu and navigate to Networking >> Hybrid Connectivity >> VPN. ui-gcp-navigation-vpn

  3. Click Create VPN Connection.

  4. Select High-availability (HA) VPN and click Continue.

  5. Enter the following information:

    • VPN Gateway name: gcp-vpn-to-aws
    • Network: Select default
    • Region: Select us-east1
    • VPN tunnel inner IP stack type: - Select IPv4 (single stack)

  6. Click Create & Continue.

  7. Make note of the provided IP addresses for the new VPN gateway. ui-gcp-create-vpn-ip-addresses

    Note

    The IP addresses generated for you will be different from the addresses in the example screenshot.

  8. Remain logged into your GCP account. You will return to this page to continue with the configuration.

Create AWS VPN

Now that you have the IP addresses for the GCP VPN gateway, you can begin the setup of the AWS side of the VPN.

  1. Open a new browser (or browser tab) and log into your AWS account.

  2. Verify you are in us-east-1 (N.Virginia). ui-aws-region-menu

  3. From the AWS console click the Services menu and navigate to Networking & Content Delivery >> VPC. ui-aws-navigation-vpc

  4. Click Customer gateways in the left navigation menu.

  5. Click Create customer gateway and enter the following information:

    • Name tag - optional: cgw-in-gcp
    • BGP ASN: 65100
    • IP address: Enter the IP address for interface 0 from the GCP VPN gateway ui-gcp-vpn-appliance-int0

  6. Click Create customer gateway.

  7. Click Transit gateways in the left navigation menu.

  8. Click Create transit gateway and enter the following information:

    • Name tag: tgw-for-hcp
    • Amazon side Autonomous System Number (ASN): 64512

  9. Click Create transit gateway.

  10. Click Site-to-Site VPN connections in the left navigation menu.

  11. Click Create VPN connection and enter the following information:

    • Name tag - optional: aws-vpn-to-gcp
    • Target gateway type: Select Transit gateway
    • Transit gateway: Select the tgw-for-hcp
    • Customer gateway: Select Existing
    • Customer gateway ID: Select cgw-in-gcp

  12. Click Create VPN connection.

  13. Wait for the State to change from Pending to Available then select aws-vpn-to-gcp.

  14. Click Download configuration.

  15. In the Vendor pulldown menu, select Generic and then click Download.

    You will use the values provided in the configuration file to complete the VPN and routing setup on the GCP side.

Review the AWS configuration file

To complete the VPN setup you need to get the relevant VPN configuration from the downloaded configuration file.

  1. Open the configuration file in your preferred text editor.

  2. Locate the IPSec Tunnel #1 section.

  3. In section #1: Internet Key Exchange Configuration, make note of the Pre-Shared Key.

    #1: Internet Key Exchange Configuration

...snip...

  - IKE version              : IKEv1
  - Authentication Method    : Pre-Shared Key
  - Pre-Shared Key           : CJ.ykyfeSOr61oWvjk2C5dbecuAW2wVs
  - Authentication Algorithm : sha1
  - Encryption Algorithm     : aes-128-cbc
  - Lifetime                 : 28800 seconds
  - Phase 1 Negotiation Mode : main
  - Diffie-Hellman           : Group 2

  4. Locate section #3: Tunnel Interface Configuration.

  5. Make note of the Outside IP Addresses and Inside IP Addresses.

    #3: Tunnel Interface Configuration

...snip...

Outside IP Addresses:
  - Customer Gateway                : 35.242.15.66
  - Virtual Private Gateway         : 3.212.197.15

Inside IP Addresses
  - Customer Gateway                   : 169.254.221.74/30
  - Virtual Private Gateway            : 169.254.221.73/30

Configure your tunnel to fragment at the optimal size:
  - Tunnel interface MTU     : 1436 bytes

  6. Remain logged into your AWS account. You will return to this page to continue with the configuration.

Connect VPN between GCP and AWS

  1. Return to the GCP console.

    Note

    You should return to step 2 Add VPN tunnels.

  2. Under Peer VPN gateway select On-prem or Non Google Cloud.

  3. In the Peer VPN gateway name pulldown menu, select Create new peer VPN gateway. ui-gcp-vpn-wizard-create-peer

  4. Enter the following information:

    • Name: cgw-in-aws
    • Interfaces: Select one interface
    • Interface 0 IP address: Enter the outside IP address for the Virtual Private Gateway from the downloaded AWS configuration file. For example, using the sample configuration above enter 3.212.197.15.

  5. Click Create. You will be returned to the Create a VPN wizard.

    Create a single VPN tunnel will be automatically selected for you.

  6. Under Routing options click the Cloud Router pulldown menu and select Create new router.

  7. Enter the following information:

    • Name: gcp-default-cr
    • Google ASN: 65100

    Note

    Advertise all subnets visible to the Cloud Router (Default) is used for this tutorial. For production configurations, you should follow your organizations network and security practices to choose between advertising all routes, or creating custom routes.

  8. Click Create. You will be returned to the Create a VPN wizard.

  9. In the Name text box enter aws-vpn-tunnel-1.

  10. In the IKE pre-shared key text box, enter the pre-shared key from the AWS configuration file. For example, using the sample configuration above enter CJ.ykyfeSOr61oWvjk2C5dbecuAW2wVs.

  11. Click Create & continue.

  12. Under Configure BGP sessions click Configure BGP session. ui-gcp-vpn-wizard-config-bgp

  13. Enter the following information:

    • Name: aws-bgp-peer
    • Peer ASN: 64512

  14. Click Save and continue. You will be returned to the Create a VPN wizard.

  15. Click Save BGP configuration.

  16. Under Summary and reminder click OK.

  17. From the Cloud VPN Tunnels tab, click aws-vpn-tunnel-1.

  18. Click Edit BGP session.

  19. Change the Cloud Router BGP IPv4 address to inside IP address for the Customer Gateway from the downloaded AWS configuration file. For example, using the sample configuration above enter the Inside IP Address for the Customer Gateway, 169.254.221.74.

  20. Change the BGP peer Router BGP IPv4 address to inside IP address for the Virtual Private Gateway from the downloaded AWS configuration file. For example, using the sample configuration above enter the Inside IP Address for the Virtual Private Gateway, 169.254.221.73.

  21. Click Save and continue.

  22. The BPG session status should change to BGP established. ui-gcp-bgp-established

    Tip

    If the status does not change, refresh the browser page (or browser tab).

Create and connect HCP resources

Now that you have established a connection from your GCP account to the AWS account being used as a transit network, you will deploy and configure a HashiCorp Virtual Network (HVN) and connect the HVN to the AWS transit gateway.

Create HVN and transit gateway attachment

Note

Each HashiCorp Virtual Network (HVN) is created in a project based on a user selected region. The HVN hosts other HCP resources such as HCP Vault and HCP Consul clusters.

  1. Open a new browser (or browser tab) and log into your HCP account.

  2. Click HashiCorp Virtual Networks in the left navigation menu.

  3. Click Create network and enter the following information:

    • Network name: hvn
    • Provider: Select Amazon Web Services
    • Region selection: Select N. Virginia (us-east-1).

  4. Click Create network.

    Wait for the HVN to be available with a status of Stable before proceeding. ui-hcp-hvn-stable

  5. Click Transit gateway attachments in the left navigation menu.

  6. Click Create attachment and click the Web console tab.

  7. Enter tgw-attach-hcp in the Attachment ID field.

  8. Copy the AWS Account ID.

  9. Remain logged into your HCP account. You will return to this page to continue with the configuration.

Create AWS resource share

  1. Return to the AWS console and navigate to Resource Access Manager.

  2. Click Create a resource share.

  3. In the Name field enter hcp-tgw-ram.

  4. Under Resources - optional select Transit Gateways.

  5. Click the checkbox for tgw-for-hcp.

  6. Click Next and then click Next again.

  7. Under Principals paste the AWS account ID you copied from the HCP portal and click Add.

  8. Click Next.

  9. Click Create resource share.

  10. Copy the ARN for the resource share. ui-aws-ram-arn

  11. Navigate back to the VPC console and click Transit gateways in the left navigation menu.

  12. Copy the transit gateway ID for tgw-for-hcp.

Complete transit gateway attachment

  1. Return to the HCP portal.

  2. Enter the following information:

    • Transit gateway ID: ID for the transit gateway created previously in this tutorial.
    • Resource share ARN: ARN for the resource share created previously in this tutorial.

  3. Click Create attachment. hcp-ui-aws-vpc-attach

  4. Return to the AWS VPC console and click Transit gateway attachments in the left navigation menu.

  5. Click the checkbox for the attachment with a resource type of VPC (it should be in the Pending Acceptance state).

  6. Click the Actions pulldown menu and select Accept transit gateway attachment.

  7. Click Accept.

  8. Wait for the state to change from Pending to Available. ui-aws-tgwa-available

Update HCP route table

  1. Switch back to the HCP Portal.

  2. Click Route table in the left navigation menu.

  3. Click Create route and enter the following information:

    • Route ID: route-aws-vpc
    • Destinations: Enter the subnet for your AWS VPC (You can retrieve this by clicking Your VPCs in the AWS console)
    • Target: Select tgw-attach-hcp

  4. Click Create route.

  5. Click Create route again and enter the following information:

    • Route ID: route-gcp-vpc
    • Destinations: Enter the subnet for your GCP VPC (You can retrieve this by clicking VPC network >> VPC networks in the GCP console)
    • Target: Select tgw-attach-hcp

  6. Click Create route.

    Note

    For simplicity you created routes for the entire VPC in AWS and GCP. For production configurations, you should follow your organizations network and security practices to choose between creating routes for the entire VPC, or specific subnets.

Validate networking configuration

You have created all the necessary resources in your AWS, GCP, and HCP accounts. To validate the configuration, you will now deploy a private HCP Vault cluster and create a VM instance in GCP to test access across the AWS transit VPC.

  1. While still logged into the HCP Portal, click Back to Networks and click Vault in the left navigation menu.

  2. Under Start from scratch click Create cluster.

  3. Keep all defaults and verify the HVN you connected to the AWS transit gateway is selected.

  4. Click the slider for Allow public connections from outside your selected network to disable public access. ui-hcp-public-access-disabled

  5. Click Create cluster.

  6. While the cluster is being created, switch back to the GCP console.

  7. Click the hamburger menu and navigate to Compute Engine >> VM instances.

  8. Click Create instance and enter the following information:

    • Name: test-hcp
    • Region: Select us-east1

  9. Keep all other defaults and click Create.

  10. When the instance becomes available, click SSH. A new window will open and log you into the VM.

  11. From the HCP Portal, click Generate token then click Copy to copy the token.

  12. In the SSH session for your GCP VM instance, create an environment variable named VAULT_TOKEN.

    $ export VAULT_TOKEN=<copied-token-value>

  13. From the HCP Portal, under Cluster URLs click Private to copy the private HCP Vault address.

  14. In the SSH session for your GCP VM instance, create an environment variable named VAULT_ADDR.

    $ export VAULT_ADDR=<copied-address-value>

  15. Create an environment variable named VAULT_NAMESPACE with a value of admin.

    $ export VAULT_NAMESPACE=admin

  16. Validate the connection to the private HCP Vault cluster by looking up your token information using cURL.

    $ curl \
 --header "X-Vault-Token: $VAULT_TOKEN" \
 --header "X-Vault-Namespace: $VAULT_NAMESPACE" \
 --request LIST \
 $VAULT_ADDR/v1/auth/token/accessors

  17. The lookup will return information about the provided token.

    Example output:

    $ curl \
 --header "X-Vault-Token: $VAULT_TOKEN" \
 --header "X-Vault-Namespace: $VAULT_NAMESPACE" \
 --request LIST \
 $VAULT_ADDR/v1/auth/token/accessors

{"request_id":"36116197-e3f1-17c0-1b63-b7b0cb1c7f9a","lease_id":"","renewable":false,"lease_duration":0,"data":{"keys":["7G9uBnJW08zEwjnQBs73b0q8.BZD6Q"]},"wrap_info":null,"warnings":null,"auth":null}

    You have successfully made a request to a private HCP Vault cluster from your GCP VM instance through a transit AWS VPC.

Cleanup

To avoid unnecessary charges, you should clean up any resources you created during this tutorial.

GCP

  • Delete the test-hcp VM instance
  • Delete the Cloud VPN tunnel
  • Delete the Cloud VPN gateway
  • Delete the peer VPN gateway
  • Delete the cloud router

AWS

  • Delete the site-to-site VPN
  • Delete the transit gateway attachments
  • Delete the transit gateway
  • Delete the customer gateway

HCP

  • Delete the HCP Vault cluster
  • Delete the HVN

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