通過CloudFormation爲已有表添加自動縮放比例

我們的團隊非常高興地看到針對AWS DynamoDB宣佈的自動縮放功能，並且在通過在Web界面中添加配置嘗試它時，我們發現這很適合我們的應用程序'需要。通過CloudFormation爲已有表添加自動縮放比例

但是，嘗試通過CF添加相同的配置已被證明有點複雜。以下示例在本文中提供 - http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-dynamodb-table.html#cfn-dynamodb-table-examples-application-autoscaling - 下面是結果，它不起作用。堆棧細節：

17:02:25 UTC+0300 UPDATE_ROLLBACK_IN_PROGRESS AWS::CloudFormation::Stack my-stack The following resource(s) failed to create: [WriteCapacityScalableTarget]. 17:02:24 UTC+0300 CREATE_FAILED AWS::ApplicationAutoScaling::ScalableTarget WriteCapacityScalableTarget table/TableName|dynamodb:table:WriteCapacityUnits|dynamodb already exists 17:02:18 UTC+0300 CREATE_IN_PROGRESS AWS::ApplicationAutoScaling::ScalableTarget WriteCapacityScalableTarget 17:02:15 UTC+0300 CREATE_COMPLETE AWS::IAM::Role ScalingRole 17:01:42 UTC+0300 CREATE_IN_PROGRESS AWS::IAM::Role ScalingRole Resource creation Initiated 17:01:42 UTC+0300 CREATE_IN_PROGRESS AWS::IAM::Role ScalingRole 17:01:37 UTC+0300 UPDATE_IN_PROGRESS AWS::CloudFormation::Stack my-stack User Initiated

我的CF腳本如下：

{ 
    "Resources": { 
    "MyCustomTableName": { 
     "Type": "AWS::DynamoDB::Table", 
     "Properties": { 
     "TableName": "TableName", 
     "AttributeDefinitions": [ 
      { 
      "AttributeName": "someAttribute1:someAttribute2", 
      "AttributeType": "S" 
      } 
     ], 
     "KeySchema": [ 
      { 
      "AttributeName": "someAttribute1:someAttribute2", 
      "KeyType": "HASH" 
      } 
     ], 
     "ProvisionedThroughput": { 
      "ReadCapacityUnits": 1, 
      "WriteCapacityUnits": 1 
     }, 
     "StreamSpecification": { 
      "StreamViewType": "NEW_AND_OLD_IMAGES" 
     } 
     } 
    }, 
    "WriteCapacityScalableTarget": { 
     "Type": "AWS::ApplicationAutoScaling::ScalableTarget", 
     "Properties": { 
     "MaxCapacity": 30, 
     "MinCapacity": 1, 
     "ResourceId": { 
      "Fn::Join": [ 
      "/", 
      [ 
       "table", 
       { 
       "Ref": "MyCustomTableName" 
       } 
      ] 
      ] 
     }, 
     "RoleARN": { 
      "Fn::GetAtt": [ 
      "ScalingRole", 
      "Arn" 
      ] 
     }, 
     "ScalableDimension": "dynamodb:table:WriteCapacityUnits", 
     "ServiceNamespace": "dynamodb" 
     } 
    }, 
    "ScalingRole": { 
     "Type": "AWS::IAM::Role", 
     "Properties": { 
     "AssumeRolePolicyDocument": { 
      "Version": "2012-10-17", 
      "Statement": [ 
      { 
       "Effect": "Allow", 
       "Principal": { 
       "Service": [ 
        "application-autoscaling.amazonaws.com" 
       ] 
       }, 
       "Action": [ 
       "sts:AssumeRole" 
       ] 
      } 
      ] 
     }, 
     "Path": "/", 
     "Policies": [ 
      { 
      "PolicyName": "root", 
      "PolicyDocument": { 
       "Version": "2012-10-17", 
       "Statement": [ 
       { 
        "Effect": "Allow", 
        "Action": [ 
        "dynamodb:DescribeTable", 
        "dynamodb:UpdateTable", 
        "cloudwatch:PutMetricAlarm", 
        "cloudwatch:DescribeAlarms", 
        "cloudwatch:GetMetricStatistics", 
        "cloudwatch:SetAlarmState", 
        "cloudwatch:DeleteAlarms" 
        ], 
        "Resource": "*" 
       } 
       ] 
      } 
      } 
     ] 
     } 
    }, 
    "WriteScalingPolicy": { 
     "Type": "AWS::ApplicationAutoScaling::ScalingPolicy", 
     "Properties": { 
     "PolicyName": "WriteAutoScalingPolicy", 
     "PolicyType": "TargetTrackingScaling", 
     "ScalingTargetId": { 
      "Ref": "WriteCapacityScalableTarget" 
     }, 
     "TargetTrackingScalingPolicyConfiguration": { 
      "TargetValue": 70.0, 
      "ScaleInCooldown": 60, 
      "ScaleOutCooldown": 60, 
      "PredefinedMetricSpecification": { 
      "PredefinedMetricType": "DynamoDBWriteCapacityUtilization" 
      } 
     } 
     } 
    } 
    } 
}

如果任何人都可以提供一些線索，爲什麼發生這種情況，我會非常感激:)

來源

2017-09-01 Alexey Danilov

奇怪的是，似乎只有一個特定的表存在問題 - 並且通過控制檯添加或刪除自動縮放無助於 - 腳本仍然因提到的錯誤而失敗。解決此問題的唯一方法是通過CF更新預配置容量（不可擴展），然後才能通過相同的CF腳本添加自動縮放。 –

去通過該錯誤消息

CREATE_FAILED AWS::ApplicationAutoScaling::ScalableTarget WriteCapacityScalableTarget table/TableName|dynamodb:table:WriteCapacityUnits|dynamodb already exists

您正在創建名爲"TableName": "TableName"的DynamoDB資源。在一個區域內不能有兩個名字相同的dynamoDB表。

轉到DynamoDB控制檯並檢查是否有任何此類表並將其刪除。發佈模板應該可以正常工作。選項2：如果要繼續使用現有表，則可以從CF模板中刪除AWS :: DynamoDB :: Table資源。

來源

2017-09-02 08:49:49 krisnik

謝謝。我從錯誤消息中得到的印象是，該表的WriteCapacityUnits已經創建 - 因爲它們已經是，因此表已經存在。但是不刪除表資源本身意味着表被刪除？它有數據，我不願意爲此丟失（或遷移）數據。因此，爲了清楚起見，table資源很早以前就已經創建，我只想添加自動調節功能 - 通過將WriteCapacityScalableTarget，ScalingRole和WriteScalingPolicy引入到CF模板中。 –

我嘗試模擬相同的內容。首先使用CF模板創建DynamoDB表，然後將WritingCapacityScalableTarget，ScalingRole和WriteScalingPolicy添加到CF模板並執行更新堆棧。進展順利。那麼，是否有可能通過控制檯測試了一些東西，並忘記清除它？ – krisnik

通過CloudFormation爲已有表添加自動縮放比例

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