Azure - AWS VPN & BGP (translated from https://github.com/vmisson/terraform-azure-aws-vpn/blob/main/aws.tf)

aws-vpn-to-azure.yaml

AWSTemplateFormatVersion: '2010-09-09'
Description: AWS EU West 1 VPN gateway with connections to Azure.

Parameters:
  VpcId:
    Type: AWS::EC2::VPC::Id
    Description: ID of the existing VPC.

  SubnetId:
    Type: AWS::EC2::Subnet::Id
    Description: ID of the existing Subnet.

  AzurePrimaryGatewayIp:
    Type: String
    Description: Public IP address of the primary Azure gateway.

  AzureSecondaryGatewayIp:
    Type: String
    Description: Public IP address of the secondary Azure gateway.

  BgpAsn:
    Type: Number
    Default: 65515
    Description: BGP ASN for the customer gateways.

  Tunnel1PrimaryCidr:
    Type: String
    Default: 169.254.21.0/30
    Description: Inside CIDR for tunnel 1 of the primary VPN connection.

  Tunnel2PrimaryCidr:
    Type: String
    Default: 169.254.21.4/30
    Description: Inside CIDR for tunnel 2 of the primary VPN connection.

  Tunnel1SecondaryCidr:
    Type: String
    Default: 169.254.22.0/30
    Description: Inside CIDR for tunnel 1 of the secondary VPN connection.

  Tunnel2SecondaryCidr:
    Type: String
    Default: 169.254.22.4/30
    Description: Inside CIDR for tunnel 2 of the secondary VPN connection.

Resources:
  VPNGateway:
    Type: AWS::EC2::VPNGateway
    Properties:
      Type: ipsec.1
      Tags:
        - Key: Name
          Value: aws-gateway-001

  VPNGatewayAttachment:
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      VpcId: !Ref VpcId
      VpnGatewayId: !Ref VPNGateway

  VPNGatewayRoutePropagation:
    Type: AWS::EC2::VPNGatewayRoutePropagation
    Properties:
      RouteTableIds:
        - !Ref RouteTable
      VpnGatewayId: !Ref VPNGateway

  CustomerGatewayPrimary:
    Type: AWS::EC2::CustomerGateway
    Properties:
      BgpAsn: !Ref BgpAsn
      IpAddress: !Ref AzurePrimaryGatewayIp
      Type: ipsec.1
      Tags:
        - Key: Name
          Value: azure-gateway-001-primary

  CustomerGatewaySecondary:
    Type: AWS::EC2::CustomerGateway
    Properties:
      BgpAsn: !Ref BgpAsn
      IpAddress: !Ref AzureSecondaryGatewayIp
      Type: ipsec.1
      Tags:
        - Key: Name
          Value: azure-gateway-001-secondary

  VPNConnectionPrimary:
    Type: AWS::EC2::VPNConnection
    Properties:
      VpnGatewayId: !Ref VPNGateway
      CustomerGatewayId: !Ref CustomerGatewayPrimary
      Type: ipsec.1
      VpnTunnelOptionsSpecifications:
        - TunnelInsideCidr: !Ref Tunnel1PrimaryCidr
        - TunnelInsideCidr: !Ref Tunnel2PrimaryCidr
      Tags:
        - Key: Name
          Value: azure-vpn-001-primary

  VPNConnectionSecondary:
    Type: AWS::EC2::VPNConnection
    Properties:
      VpnGatewayId: !Ref VPNGateway
      CustomerGatewayId: !Ref CustomerGatewaySecondary
      Type: ipsec.1
      VpnTunnelOptionsSpecifications:
        - TunnelInsideCidr: !Ref Tunnel1SecondaryCidr
        - TunnelInsideCidr: !Ref Tunnel2SecondaryCidr
      Tags:
        - Key: Name
          Value: azure-vpn-001-secondary