CloudFormationでクロススタック参照(YAML版)

はじめに

今回はCloudFormationのクロススタック参照を試してみたいと思います。
前回作成したVPCテンプレートを修正し、S3＆VPCエンドポイントのテンプレートから参照できるようにいたします。

AWS CloudFormation で YAML テンプレートとクロススタックリファレンスをサポート

テンプレートファイル

VPC作成テンプレートでOutputsセクションを追加し、
ルートテーブルとサブネットをエクスポートするように記載しております。
※Exportする名前はAWSアカウントおよびリージョンで一意にする必要があるので
　被らないように命名規則を作ってください。
　今回はリソース同様、<環境>-<システム名>-<リソース名>という形にしてます。

以下、VPC作成テンプレート

CFn_CreateVPCsubnet.yaml

AWSTemplateFormatVersion: '2010-09-09'
Description:
  VPC & subnet create
Parameters:
  EnvType:
    Description: Environment type.
    Default: dev
    Type: String
    AllowedValues:
      - dev
      - mnt
      - prd
    ConstraintDescription: must specify dev or mnt or prd.
  ProjectId:
    Description: Project name id.
    Type: String
    MinLength: "3"
    MaxLength: "3"
    AllowedPattern: "[a-zA-Z0-9]*"
    ConstraintDescription: must specify Project id.

Resources:
# Create VPC
  MyVPC:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: 10.0.0.0/24
      EnableDnsSupport: 'true'
      EnableDnsHostnames: 'true'
      InstanceTenancy: default
      Tags:
      - Key: Name
        Value: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"vpc" ] ]

# Create Public RouteTable
  PublicRouteTable:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref MyVPC
      Tags:
      - Key: Name
        Value: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"pub-route" ] ]

# Create Private RouteTable
  PrivateRouteTable:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref MyVPC
      Tags:
      - Key: Name
        Value: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"pri-route" ] ]

# Create Public Subnet A
  PublicSubnetA:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref MyVPC
      CidrBlock: 10.0.0.0/27
      AvailabilityZone: "ap-northeast-1a"
      Tags:
      - Key: Name
        Value: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"PublicSunetA" ] ]
  PubSubnetARouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref PublicSubnetA
      RouteTableId: !Ref PublicRouteTable

# Create Public Subnet C
  PublicSubnetC:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref MyVPC
      CidrBlock: 10.0.0.32/27
      AvailabilityZone: "ap-northeast-1c"
      Tags:
      - Key: Name
        Value: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"PublicSunetC" ] ]
  PubSubnetCRouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref PublicSubnetC
      RouteTableId: !Ref PublicRouteTable

# Create Private Subnet A
  PrivateSubnetA:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref MyVPC
      CidrBlock: 10.0.0.64/27
      AvailabilityZone: "ap-northeast-1a"
      Tags:
      - Key: Name
        Value: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"PrivateSubnetA" ] ]
  PriSubnetARouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref PrivateSubnetA
      RouteTableId: !Ref PrivateRouteTable

# Create Private Subnet C
  PrivateSubnetC:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref MyVPC
      CidrBlock: 10.0.0.96/27
      AvailabilityZone: "ap-northeast-1c"
      Tags:
      - Key: Name
        Value: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"PrivateSubnetC" ] ]
  PriSubnetCRouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref PrivateSubnetC
      RouteTableId: !Ref PrivateRouteTable

# Create InternetGateway
  myInternetGateway:
    Type: "AWS::EC2::InternetGateway"
    Properties:
      Tags:
      - Key: Name
        Value: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"igw" ] ]
  AttachGateway:
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      VpcId: !Ref MyVPC
      InternetGatewayId: !Ref myInternetGateway

# Create VPNGateway
  myVPNGateway:
    Type: "AWS::EC2::VPNGateway"
    Properties:
      Type: ipsec.1
      Tags:
      - Key: Name
        Value: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"vgw" ] ]
  AttachVpnGateway:
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      VpcId: !Ref MyVPC
      VpnGatewayId: !Ref myVPNGateway

# Route for InternetGateway or VPNGateway
  myRoute:
    Type: AWS::EC2::Route
    DependsOn: myInternetGateway
    Properties:
      RouteTableId: !Ref PublicRouteTable
      DestinationCidrBlock: 0.0.0.0/0
      GatewayId: !Ref myInternetGateway
      #GatewayId: !Ref myVPNGateway

Outputs:
  StackVPC:
    Description: The ID of the VPC
    Value: !Ref MyVPC
    Export:
      Name: !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId" , "vpcid"]]

  PublicRouteTable:
    Description: The ID of the PublicRouteTable
    Value: !Ref PublicRouteTable
    Export:
      Name: !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId", "PublicRouteTable"]]

  PrivateRouteTable:
    Description: The ID of the PrivateRouteTable
    Value: !Ref PrivateRouteTable
    Export:
      Name: !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId", "PrivateRouteTable"]]

  StackPubSubnetA:
    Description: The ID of the VPC Subnet
    Value: !Ref PublicSubnetA
    Export:
      Name: !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId", "PublicSubnetA"]]

  StackPubSubnetB:
    Description: The ID of the VPC Subnet
    Value: !Ref PublicSubnetC
    Export:
      Name: !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId", "PublicSubnetC"]]

  StackPriSubnetA:
    Description: The ID of the VPC Subnet
    Value: !Ref PrivateSubnetA
    Export:
      Name: !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId", "PrivateSubnetA"]]

  StackPriSubnetB:
    Description: The ID of the VPC Subnet
    Value: !Ref PrivateSubnetC
    Export:
      Name: !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId", "PrivateSubnetC"]]

"Fn::ImportValue"の箇所で、上記のエクスポートした情報をインポートしています。
VPCとルートテーブルを利用しています。

以下、S3＆VCPエンドポイント作成

CFn_CreateS3.yaml

AWSTemplateFormatVersion: '2010-09-09'
Description:
  S3 & VPC Endpoint create
Parameters:
  EnvType:
    Description: Environment type.
    Default: dev
    Type: String
    AllowedValues:
      - dev
      - mnt
      - prd
    ConstraintDescription: must specify dev or mnt or prd.
  ProjectId:
    Description: Project name id.
    Type: String
    MinLength: "3"
    MaxLength: "3"
    AllowedPattern: "[a-zA-Z0-9]*"
    ConstraintDescription: must specify Project id.

Resources:
# Create S3 by log
  LogS3:
    Type: "AWS::S3::Bucket"
    Properties:
      BucketName: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"logbucket" ] ]
      Tags:
      - Key: Name
        Value: !Join [ "-", [ "Ref":"EnvType" , "Ref":"ProjectId" ,"LogBucket" ] ]

  LogS3Endpoint:
    Type: "AWS::EC2::VPCEndpoint"
    Properties:
      RouteTableIds:
        - { "Fn::ImportValue": !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId", "PublicRouteTable"]] }
        - { "Fn::ImportValue": !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId", "PrivateRouteTable"]] }
      ServiceName:
        !Sub "com.amazonaws.${AWS::Region}.s3"
      VpcId: { "Fn::ImportValue": !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId" , "vpcid"]] }

Outputs:
  LogS3:
    Description: Log S3 Bucket
    Value: !Ref LogS3
    Export:
      Name: !Join [ "-", [ "Ref":"EnvType", "Ref":"ProjectId", "LogBucket"]]

ちなみに短縮形多用しておりますが、ImportValueのところは以下のエラーがでたため、短縮形の利用を諦めました。
```
Template validation error: Template format error: YAML not well-formed. (line 36, column 26)

まとめ

組み込み関数の組み合わせでエラーが多発して手こずりましたが、なんとかできました。
次はEC2インスタンスに挑戦したいと思います！

ちなみにエンドポイント作成はクロススタック参照せず、
VPC作成テンプレートに入れたほうがよいと後から思いました笑