VPC 中的 AWS Lambda 有时无法访问互联网

Question

我有部署到 VPC 的 Lambda。

此部署有下一个配置：

专有网络 (192.168.0.0/16)
Public 子网 A (192.168.32.0/20) 有 NAT 网关和路由 0.0.0.0/0 到互联网网关
私有子网 A (192.168.48.0/20) 有到 NAT 网关的路由 0.0.0.0/0
私有子网 B (192.168.64.0/20)

Lambda 有自己的安全组和对 "Private Subnet A" 和 "Private Subnet B"

的引用

我有一个奇怪的问题：有时 Lambda 无法访问互联网。第 3 方服务正常工作。

更奇怪的是，Lambda 获取的 IP 是 127.0.0.1、169.254.76.13、169.254.79.1 而不是来自子网（192.168.48.0/20 和 192.168.64.0/20）的 IP。

错误：

Error: connect ETIMEDOUT x.x.x.x:443
at Object._errnoException (util.js:1022:11)
at _exceptionWithHostPort (util.js:1044:20)
at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1198:14)

部署架构：

这里是完整的 CloudFormation 模板：

    ---
AWSTemplateFormatVersion: '2010-09-09'
Description: 'Base Infrastructure'
Metadata:
  'AWS::CloudFormation::Interface':
    ParameterGroups:
    - Label:
        default: 'VPC Parameters'
      Parameters:
      - VpcId
      - InternetGatewayId
Parameters:
  VpcId:
    Type: String
  InternetGatewayId:
    Type: String
Resources:
  SubnetAPublic:
    Type: 'AWS::EC2::Subnet'
    Properties:
      AvailabilityZone: !Select [0, !GetAZs '']
      CidrBlock: !Sub '192.168.32.0/20'
      MapPublicIpOnLaunch: true
      VpcId: !Sub '${VpcId}'
  SubnetAPrivate:
    Type: 'AWS::EC2::Subnet'
    Properties:
      AvailabilityZone: !Select [0, !GetAZs '']
      CidrBlock: !Sub '192.168.48.0/20'
      VpcId: !Sub '${VpcId}'
  SubnetBPrivate:
    Type: 'AWS::EC2::Subnet'
    Properties:
      AvailabilityZone: !Select [1, !GetAZs '']
      CidrBlock: !Sub '192.168.64.0/20'
      VpcId: !Sub '${VpcId}'
  RouteTablePublic:
    Type: 'AWS::EC2::RouteTable'
    Properties:
      VpcId: !Sub '${VpcId}'
  RouteTablePrivate:
    Type: 'AWS::EC2::RouteTable'
    Properties:
      VpcId: !Sub '${VpcId}'
  RouteTableBPrivate:
    Type: 'AWS::EC2::RouteTable'
    Properties:
      VpcId: !Sub '${VpcId}'
  RouteTableAssociationAPublic:
    Type: 'AWS::EC2::SubnetRouteTableAssociation'
    Properties:
      SubnetId: !Ref SubnetAPublic
      RouteTableId: !Ref RouteTablePublic
  RouteTableAssociationAPrivate:
    Type: 'AWS::EC2::SubnetRouteTableAssociation'
    Properties:
      SubnetId: !Ref SubnetAPrivate
      RouteTableId: !Ref RouteTablePrivate
  RouteTableAssociationBPrivate:
    Type: 'AWS::EC2::SubnetRouteTableAssociation'
    Properties:
      SubnetId: !Ref SubnetBPrivate
      RouteTableId: !Ref RouteTableBPrivate
  EIP:
    Type: 'AWS::EC2::EIP'
    Properties:
      Domain: vpc
  NatGateway:
    Type: 'AWS::EC2::NatGateway'
    Properties:
      AllocationId: !GetAtt 'EIP.AllocationId'
      SubnetId: !Ref SubnetAPublic
  RouteTablePublicInternetRoute:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref RouteTablePrivate
      DestinationCidrBlock: '0.0.0.0/0'
      NatGatewayId: !Ref NatGateway
  RouteTablePublicInternetRoute2:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref RouteTablePublic
      DestinationCidrBlock: '0.0.0.0/0'
      GatewayId: !Sub '${InternetGatewayId}'
  ServerlessSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: SecurityGroup for Serverless Functions
      VpcId: !Sub '${VpcId}'
  ServerlessSecurityGroupIngress:
    Type: AWS::EC2::SecurityGroupIngress
    Properties:
      GroupId: !Ref ServerlessSecurityGroup
      IpProtocol: -1
      SourceSecurityGroupId: !Ref ServerlessSecurityGroup

知道我做错了什么吗？

P.S.: 我发现了类似的问题AWS VPC Lambda Function keeps losing internet access and Why AWS lambda functions In a VPC sometimes timeout and sometimes work fine?

UPD

已添加路线，现在可以使用了

  RouteTableBPrivateInternetRoute:
    Type: AWS::EC2::Route
      Properties:
        RouteTableId: !Ref RouteTableBPrivate
        DestinationCidrBlock: '0.0.0.0/0'
        NatGatewayId: !Ref NatGateway

Answer 1

要使 VPC 内的 AWS Lambda 函数运行能够访问 VPC 外的资源（例如 Internet），它必须位于具有 NAT 网关的私有子网中。在您的实例中，私有子网 A 是唯一具有适当配置以允许 Lambda 函数访问 Internet 的子网。因此，您需要将 Lambda 函数的配置编辑为仅在该子网中运行。

Answer 2

您是否已选择 public 子网作为您的 lambda 运行所在的子网之一？

lambda 只能在运行私有子网中访问互联网，因此请转到 AWS 控制台上的 lambda 页面，取消选择 public 子网并保存，问题应该不会再发生了。

VPC 中的 AWS Lambda 有时无法访问互联网

AWS Lambda in VPC sometimes doesn't have internet access

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