AWS ELB：503 服務暫時不可用

Question

我正在嘗試按照此示例repo將微服務部署到 AWS ECS。 在這里，負載均衡器用於不同 docker 服務之間的網絡。 我已經根據我的需要調整了 cloudformation 模板，並且只部署了一項服務，即網絡服務器。 我希望公開訪問 Web 界面並添加此服務隨后與之通信的其他服務。 但是，我目前正在努力使用負載均衡器的 URL 來啟動網絡服務器。 如果我使用公共 IP 直接訪問 EC2 實例，則可以訪問該接口。 但是，如果我轉到負載均衡器 DNS，則會收到503 Service Temporarily Unavailable 。 我檢查了AWS文檔，但Web服務的目標群體表演的注冊目標（EC2實例），狀態healthy 。 我錯過了什么？

Parameters:
  EnvironmentName:
    Description: An environment name that will be prefixed to resource names
    Type: String

  VPC:
    Type: AWS::EC2::VPC::Id
    Description: Choose which VPC the Application Load Balancer should be deployed to

  Subnets:
    Description: Choose which subnets the Application Load Balancer should be deployed to
    Type: AWS::EC2::Subnet::Id

  PublicSubnet:
    Description: Choose which public subnet the EC2 instance should be deployed to
    Type: AWS::EC2::Subnet::Id

Resources:

  LoadBalancerSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupName: !Sub ${EnvironmentName}-loadbalancer
      GroupDescription: Access to the load balancer that sits in front of ECS
      VpcId: !Ref VPC
      SecurityGroupIngress:
        # Allow access from anywhere to our ECS services
        - CidrIp: 0.0.0.0/0
          IpProtocol: -1
      Tags:
        - Key: Name
          Value: !Sub ${EnvironmentName}-LoadBalancers

  LoadBalancer:
    Type: AWS::ElasticLoadBalancingV2::LoadBalancer
    Properties:
      Name: !Ref EnvironmentName
      Subnets:
        - !Ref Subnets
      SecurityGroups:
        - !Ref LoadBalancerSecurityGroup
      Tags:
        - Key: Name
          Value: !Ref EnvironmentName

  LoadBalancerListener:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
      LoadBalancerArn: !Ref LoadBalancer
      Port: 80
      Protocol: HTTP
      DefaultActions:
        - Type: forward
          TargetGroupArn: !Ref DefaultTargetGroup

  DefaultTargetGroup:
    Type: AWS::ElasticLoadBalancingV2::TargetGroup
    Properties:
      Name: !Sub ${EnvironmentName}-default
      VpcId: !Ref VPC
      Port: 80
      Protocol: HTTP

  ECSHostSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupName: !Sub ${EnvironmentName}-ecs-hosts
      GroupDescription: Access to the ECS hosts and the tasks/containers that run on them
      VpcId: !Ref VPC
      SecurityGroupIngress:
        # Only allow inbound access to ECS from the ELB
        - SourceSecurityGroupId: !Ref LoadBalancerSecurityGroup
          IpProtocol: -1
        - IpProtocol: tcp
          FromPort: 22
          ToPort: 22
          CidrIp: 0.0.0.0/0
        - IpProtocol: tcp
          FromPort: 80
          ToPort: 80
          CidrIp: 0.0.0.0/0
      Tags:
        - Key: Name
          Value: !Sub ${EnvironmentName}-ECS-Hosts

  ECSCluster:
    Type: AWS::ECS::Cluster
    Properties:
      ClusterName: !Ref EnvironmentName

  ECSRole:
    Type: AWS::IAM::Role
    Properties:
      Path: /
      RoleName: !Sub ${EnvironmentName}-ecs-role
      AssumeRolePolicyDocument:
        Statement:
          - Effect: Allow
            Principal:
              Service: ec2.amazonaws.com
            Action: 'sts:AssumeRole'
      ManagedPolicyArns:
        - 'arn:aws:iam::aws:policy/service-role/AmazonEC2ContainerServiceforEC2Role'
        - 'arn:aws:iam::aws:policy/service-role/AmazonEC2RoleforSSM'
        - 'arn:aws:iam::aws:policy/CloudWatchAgentServerPolicy'

  ECSInstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      Path: /
      Roles:
        - !Ref ECSRole

  EC2Webserver:
    Type: AWS::EC2::Instance
    Properties:
      AvailabilityZone: eu-central-1a
      ImageId: !Ref ECSAMI
      InstanceType: !Ref InstanceType
      IamInstanceProfile: !Ref ECSInstanceProfile
      UserData:
        Fn::Base64:
          !Sub |
          #!/bin/bash
          # Add to cluster:
          echo ECS_CLUSTER=${ECSCluster} >> /etc/ecs/ecs.config
          echo ECS_ENABLE_AWSLOGS_EXECUTIONROLE_OVERRIDE=true >> /etc/ecs/ecs.config
      SecurityGroupIds:
        - !Ref ECSHostSecurityGroup
      SubnetId: !Ref PublicSubnet
      Tags:
        - Key: Name
          Value: !Sub ${EnvironmentName}

  Service:
    Type: AWS::ECS::Service
    DependsOn: ListenerRule
    Properties:
      Cluster: !Ref Cluster
      Role: !Ref ServiceRole
      DesiredCount: !Ref DesiredCount
      TaskDefinition: !Ref TaskDefinitionWebserver
      LoadBalancers:
        - ContainerName: !Sub ${EnvironmentName}-webserver
          ContainerPort: 8080
          TargetGroupArn: !Ref TargetGroup

  TaskDefinitionWebserver:
    Type: AWS::ECS::TaskDefinition
    Properties:
      Family: !Sub ${EnvironmentName}-webserver
      ContainerDefinitions:
        - Name: !Sub ${EnvironmentName}-webserver
          Essential: true
          Image: !Ref Image
          Memory: 512
          PortMappings:
            - ContainerPort: 8080
              HostPort: 80

  TargetGroup:
    Type: AWS::ElasticLoadBalancingV2::TargetGroup
    Properties:
      Name: !Sub ${EnvironmentName}-webserver
      VpcId: !Ref VPC
      Port: 80
      Protocol: HTTP
      Matcher:
        HttpCode: 200-299
      HealthCheckIntervalSeconds: 30
      HealthCheckPath: /health
      HealthCheckProtocol: HTTP
      HealthCheckTimeoutSeconds: 10
      HealthyThresholdCount: 5

  ListenerRule:
    Type: AWS::ElasticLoadBalancingV2::ListenerRule
    Properties:
      ListenerArn: !Ref LoadBalancerListener
      Priority: 1
      Conditions:
        - Field: path-pattern
          Values:
            - /
      Actions:
        - TargetGroupArn: !Ref TargetGroup
          Type: forward

  ServiceRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub ecs-service-${AWS::StackName}
      Path: /
      AssumeRolePolicyDocument: |
        {
            "Statement": [{
                "Effect": "Allow",
                "Principal": { "Service": [ "ecs.amazonaws.com" ]},
                "Action": [ "sts:AssumeRole" ]
            }]
        }
      Policies:
        - PolicyName: !Sub ecs-service-${AWS::StackName}
          PolicyDocument:
            {
              "Version": "2012-10-17",
              "Statement":
                [
                {
                  "Effect": "Allow",
                  "Action":
                    [
                      "ec2:AuthorizeSecurityGroupIngress",
                      "ec2:Describe*",
                      "elasticloadbalancing:DeregisterInstancesFromLoadBalancer",
                      "elasticloadbalancing:Describe*",
                      "elasticloadbalancing:RegisterInstancesWithLoadBalancer",
                      "elasticloadbalancing:DeregisterTargets",
                      "elasticloadbalancing:DescribeTargetGroups",
                      "elasticloadbalancing:DescribeTargetHealth",
                      "elasticloadbalancing:RegisterTargets"
                    ],
                  "Resource": "*"
                }
                ]
            }

Outputs:

  WebsiteServiceUrl:
    Description: The URL endpoint for the website service
    Value: !Join ["", [!GetAtt LoadBalancer.DNSName, "/"]]

Answer 1

謝謝大家！ 我終於想通了，我必須做的是在我的服務重定向到/時調整路徑。 所以我只使用通配符更改了偵聽器規則：

ListenerRule:
    Type: AWS::ElasticLoadBalancingV2::ListenerRule
    Properties:
      ListenerArn: !Ref LoadBalancerListener
      Priority: 1
      Conditions:
        - Field: path-pattern
          Values:
            - [/*]
      Actions:
        - TargetGroupArn: !Ref TargetGroup
          Type: forward

Answer 2

SG 出口規則

看起來安全組 (SG) 沒有定義出口規則。 ALB 和 EC2。

  LoadBalancerSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupName: !Sub ${EnvironmentName}-loadbalancer
      GroupDescription: Access to the load balancer that sits in front of ECS
      VpcId: !Ref VPC
      SecurityGroupIngress:
        # Allow access from anywhere to our ECS services
        - CidrIp: 0.0.0.0/0
          IpProtocol: -1

相信你在EC2控制台看SG的出站規則，應該是沒有規則的。 如果這是真的，那么原因是流量可以進入 ALB 的 80 端口，但不能從 ALB 出去，

這是我的理論。 所以請添加一個出口規則來驗證？

  LoadBalancerSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupName: !Sub ${EnvironmentName}-loadbalancer
      GroupDescription: Access to the load balancer that sits in front of ECS
      VpcId: !Ref VPC
      SecurityGroupIngress:
        # Allow access from anywhere to our ECS services
        - CidrIp: 0.0.0.0/0
          IpProtocol: -1
      SecurityGroupEgress:
      - IpProtocol: tcp
        FromPort: 80
        ToPort: 80
        CidrIp: 0.0.0.0/0   # <--- Maybe better change to VPC CIDR or ECS/EC2 subnet CIDR rather than any IP.

關於EC2，因為SG是有狀態的，流量可以通過80端口到達docker容器的8080端口，響應可以通過SG返回，因為SG知道是傳入連接的響應。

而對於 ALB，來自 Internet 的傳入連接在 ALB 端口 80 處終止，然后需要建立到 EC2 實例端口 80 的新出站連接，因此需要定義一個出口規則，如果我是正確的。

  ECSHostSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupName: !Sub ${EnvironmentName}-ecs-hosts
      GroupDescription: Access to the ECS hosts and the tasks/containers that run on them
      VpcId: !Ref VPC
      SecurityGroupIngress:
        # Only allow inbound access to ECS from the ELB
        - SourceSecurityGroupId: !Ref LoadBalancerSecurityGroup
          IpProtocol: -1
        - IpProtocol: tcp
          FromPort: 22
          ToPort: 22
          CidrIp: 0.0.0.0/0
        - IpProtocol: tcp
          FromPort: 80
          ToPort: 80
          CidrIp: 0.0.0.0/0

但是，如果 EC2 實例需要安裝包或創建出站連接，則 EC2 SG 也需要出口規則。

我是

關於 ECS 服務的 IAM 角色，有預定義的 AWS 托管角色，所以我想更好地使用它們？

• AWS::ECS::服務

    "Role": {
      "Type": "AWS::IAM::Role",
      "Properties": {
        "AssumeRolePolicyDocument": {
          "Version": "2008-10-17",
          "Statement": [
            {
              "Sid": "",
              "Effect": "Allow",
              "Principal": {
                "Service": "ecs.amazonaws.com"
              },
              "Action": "sts:AssumeRole"
            }
          ]
        },
        "ManagedPolicyArns": ["arn:aws:iam::aws:policy/service-role/AmazonEC2ContainerServiceRole"]
      }
    }

由於 AWS 現在引入了 Service Linked Role，使用它應該會更好。

• Amazon ECS 的服務相關角色

  在為 Amazon ECS 引入服務相關角色之前，您需要為 Amazon ECS 服務創建一個 IAM 角色，該角色授予 Amazon ECS 所需的權限。 不再需要此角色，但可以在需要時使用。 有關更多信息，請參閱 Amazon ECS 的舊 IAM 角色。

"arn:aws:iam::${data.aws_caller_identity.current.account_id}:role/aws-service-role/ecs.amazonaws.com/AWSServiceRoleForECS"