EC2 实例上的静态页面未在 CloudFormation 中的负载均衡器后面提供

Question

我很难解决托管在 EC2 实例上的静态页面为何未通过负载均衡器提供服务的问题。

我确定 EC2 实例配置正确，因为： - 当相关安全组中允许入站 ICMP 时，我可以 ping 实例 - 当我将实例的 public 名称添加到输出部分时，我可以浏览网页（尽管我不想直接这样做，因为实例应该位于负载平衡器后面）。

所以我认为安全组 and/or 网络路由存在问题。

这里是 CloudFormation 模板的简化版本（预计在 eu-west-1 推出）：

AWSTemplateFormatVersion: 2010-09-09
Resources:
  VPC:
    Type: 'AWS::EC2::VPC'
    Properties:
      CidrBlock: 10.0.0.0/16
      InstanceTenancy: default
      EnableDnsSupport: 'true'
      EnableDnsHostnames: 'true'

  IGW:
    Type: 'AWS::EC2::InternetGateway'

  IGWAttachment:
    Type: 'AWS::EC2::VPCGatewayAttachment'
    Properties:
      VpcId: !Ref VPC
      InternetGatewayId: !Ref IGW

  PublicSubnet:
    Type: 'AWS::EC2::Subnet'
    Properties:
      CidrBlock: 10.0.0.0/24
      AvailabilityZone: eu-west-1a
      MapPublicIpOnLaunch: 'True'
      VpcId: !Ref VPC

  App:
    Type: 'AWS::EC2::Instance'
    Properties:
      DisableApiTermination: 'false'
      InstanceInitiatedShutdownBehavior: stop
      ImageId: ami-70edb016
      InstanceType: t2.micro
      Monitoring: 'false'
      UserData: >-
        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
      NetworkInterfaces:
        - AssociatePublicIpAddress: 'true'
          DeleteOnTermination: 'true'
          Description: Primary network interface
          DeviceIndex: 0
          SubnetId: !Ref PublicSubnet
          GroupSet:
            - !Ref SGApp

  ELB:
    Type: 'AWS::ElasticLoadBalancing::LoadBalancer'
    Properties:
      Subnets:
        - !Ref PublicSubnet
      Instances:
        - !Ref App
      SecurityGroups:
        - !Ref SGELB
      Listeners:
        - LoadBalancerPort: '80'
          InstancePort: '80'
          Protocol: HTTP
      HealthCheck:
        Target: 'HTTP:80/'
        HealthyThreshold: '3'
        UnhealthyThreshold: '5'
        Interval: '15'
        Timeout: '5'

  SGELB:
    Type: 'AWS::EC2::SecurityGroup'
    Properties:
      VpcId: !Ref VPC

  AllowInboundHTTPToELB:
    Type: 'AWS::EC2::SecurityGroupIngress'
    Properties:
      GroupId: !Ref SGELB
      IpProtocol: tcp
      FromPort: '80'
      ToPort: '80'
      CidrIp: 0.0.0.0/0

  SGApp:
    Type: 'AWS::EC2::SecurityGroup'
    Properties:
      VpcId: !Ref VPC

  AllowInboundHTTPFromELB:
    Type: 'AWS::EC2::SecurityGroupIngress'
    Properties:
      GroupId: !Ref SGApp
      IpProtocol: tcp
      FromPort: '80'
      ToPort: '80'
      SourceSecurityGroupId: !Ref SGELB
  RouteTable:
    Type: 'AWS::EC2::RouteTable'
    Properties:
      VpcId: !Ref VPC

  PublicRoute:
    Type: 'AWS::EC2::Route'
    Properties:
      DestinationCidrBlock: 0.0.0.0/0
      RouteTableId: !Ref RouteTable
      GatewayId: !Ref IGW

  SubnetRouteTableAssociation:
    Type: 'AWS::EC2::SubnetRouteTableAssociation'
    Properties:
      RouteTableId: !Ref RouteTable
      SubnetId: !Ref PublicSubnet

Outputs:
  LoadBalancerDNSName:
    Value: !GetAtt ELB.DNSName

Answer 1

我解密了你的UserData，发现你没有index.html，HTTP:80/默认会寻找index.html。由于没有 index.html httpd 会重定向到带有 unhealthy 302 响应代码的测试页面，正如您在评论中提到的那样 TCP:80 可以工作或使用 HTTP:80/demo.html

#!/bin/bash
yum update -y
yum install -y httpd24
service httpd start
chkconfig httpd on
groupadd www
usermod -a -G www ec2-user
chown -R root:www /var/www
chmod 2775 /var/www
find /var/www -type d -exec chmod 2775 {} +
find /var/www -type f -exec chmod 0664 {} +
echo '<html><head><title>Success!</title></head><body>Success!</body></html>' > /var/www/html/demo.html

Answer 2

一旦您的 CF 模板创建了资源，请检查负载均衡器控制台下的 ELB 中的 EC2 实例是否处于健康状态。如果它不健康，它不会将流量路由到它。

EC2 实例上的静态页面未在 CloudFormation 中的负载均衡器后面提供

Static page on EC2 instance not served behind load balancer in CloudFormation

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