amazon-dynamodb - 如何使用数据管道导出具有按需配置的DynamoDB表

Question

我曾经使用名为Export DynamoDB table to S3的数据管道模板将DynamoDB表导出到文件。我最近更新了我所有的DynamoDB表，使其具有按需配置，并且该模板不再起作用。我可以肯定这是因为旧模板指定了要消耗的DynamoDB吞吐量百分比，这与按需表无关。

我尝试将旧模板导出为JSON，删除对吞吐量百分比消耗的引用，并创建一个新管道。但是，这是不成功的。

谁能建议如何将提供吞吐量的旧式管道脚本转换为新的按需表脚本？

这是我原始的运行脚本:

{
  "objects": [
    {
      "name": "DDBSourceTable",
      "id": "DDBSourceTable",
      "type": "DynamoDBDataNode",
      "tableName": "#{myDDBTableName}"
    },
    {
      "name": "EmrClusterForBackup",
      "coreInstanceCount": "1",
      "coreInstanceType": "m3.xlarge",
      "releaseLabel": "emr-5.13.0",
      "masterInstanceType": "m3.xlarge",
      "id": "EmrClusterForBackup",
      "region": "#{myDDBRegion}",
      "type": "EmrCluster"
    },
    {
      "failureAndRerunMode": "CASCADE",
      "resourceRole": "DataPipelineDefaultResourceRole",
      "role": "DataPipelineDefaultRole",
      "scheduleType": "ONDEMAND",
      "name": "Default",
      "id": "Default"
    },
    {
      "output": {
        "ref": "S3BackupLocation"
      },
      "input": {
        "ref": "DDBSourceTable"
      },
      "maximumRetries": "2",
      "name": "TableBackupActivity",
      "step": "s3://dynamodb-emr-#{myDDBRegion}/emr-ddb-storage-handler/2.1.0/emr-ddb-2.1.0.jar,org.apache.hadoop.dynamodb.tools.DynamoDbExport,#{output.directoryPath},#{input.tableName},#{input.readThroughputPercent}",
      "id": "TableBackupActivity",
      "runsOn": {
        "ref": "EmrClusterForBackup"
      },
      "type": "EmrActivity",
      "resizeClusterBeforeRunning": "true"
    },
    {
      "directoryPath": "#{myOutputS3Loc}/#{format(@scheduledStartTime, 'YYYY-MM-dd-HH-mm-ss')}",
      "name": "S3BackupLocation",
      "id": "S3BackupLocation",
      "type": "S3DataNode"
    }
  ],
  "parameters": [
    {
      "description": "Output S3 folder",
      "id": "myOutputS3Loc",
      "type": "AWS::S3::ObjectKey"
    },
    {
      "description": "Source DynamoDB table name",
      "id": "myDDBTableName",
      "type": "String"
    },
    {
      "default": "0.25",
      "watermark": "Enter value between 0.1-1.0",
      "description": "DynamoDB read throughput ratio",
      "id": "myDDBReadThroughputRatio",
      "type": "Double"
    },
    {
      "default": "us-east-1",
      "watermark": "us-east-1",
      "description": "Region of the DynamoDB table",
      "id": "myDDBRegion",
      "type": "String"
    }
  ],
  "values": {
    "myDDBRegion": "us-east-1",
    "myDDBTableName": "LIVE_Invoices",
    "myDDBReadThroughputRatio": "0.25",
    "myOutputS3Loc": "s3://company-live-extracts/"
  }
}

这是我尝试的更新失败:

{
  "objects": [
    {
      "name": "DDBSourceTable",
      "id": "DDBSourceTable",
      "type": "DynamoDBDataNode",
      "tableName": "#{myDDBTableName}"
    },
    {
      "name": "EmrClusterForBackup",
      "coreInstanceCount": "1",
      "coreInstanceType": "m3.xlarge",
      "releaseLabel": "emr-5.13.0",
      "masterInstanceType": "m3.xlarge",
      "id": "EmrClusterForBackup",
      "region": "#{myDDBRegion}",
      "type": "EmrCluster"
    },
    {
      "failureAndRerunMode": "CASCADE",
      "resourceRole": "DataPipelineDefaultResourceRole",
      "role": "DataPipelineDefaultRole",
      "scheduleType": "ONDEMAND",
      "name": "Default",
      "id": "Default"
    },
    {
      "output": {
        "ref": "S3BackupLocation"
      },
      "input": {
        "ref": "DDBSourceTable"
      },
      "maximumRetries": "2",
      "name": "TableBackupActivity",
      "step": "s3://dynamodb-emr-#{myDDBRegion}/emr-ddb-storage-handler/2.1.0/emr-ddb-2.1.0.jar,org.apache.hadoop.dynamodb.tools.DynamoDbExport,#{output.directoryPath},#{input.tableName}",
      "id": "TableBackupActivity",
      "runsOn": {
        "ref": "EmrClusterForBackup"
      },
      "type": "EmrActivity",
      "resizeClusterBeforeRunning": "true"
    },
    {
      "directoryPath": "#{myOutputS3Loc}/#{format(@scheduledStartTime, 'YYYY-MM-dd-HH-mm-ss')}",
      "name": "S3BackupLocation",
      "id": "S3BackupLocation",
      "type": "S3DataNode"
    }
  ],
  "parameters": [
    {
      "description": "Output S3 folder",
      "id": "myOutputS3Loc",
      "type": "AWS::S3::ObjectKey"
    },
    {
      "description": "Source DynamoDB table name",
      "id": "myDDBTableName",
      "type": "String"
    },
    {
      "default": "us-east-1",
      "watermark": "us-east-1",
      "description": "Region of the DynamoDB table",
      "id": "myDDBRegion",
      "type": "String"
    }
  ],
  "values": {
    "myDDBRegion": "us-east-1",
    "myDDBTableName": "LIVE_Invoices",
    "myOutputS3Loc": "s3://company-live-extracts/"
  }
}

这是数据管道执行中的错误:

at org.apache.hadoop.mapreduce.JobSubmitter.writeSplits(JobSubmitter.java:322) at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:198) at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1341) at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1338) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1836) at org.apache.hadoop.mapreduce.Job.submit(Job.java:1338) at org.apache.hadoop.mapred.JobClient$1.run(JobClient.java:575) at org.apache.hadoop.mapred.JobClient$1.run(JobClient.java:570) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1836) at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:570) at org.apache.hadoop.mapred.JobClient.submitJob(JobClient.java

Answer 1

我为此打开了与AWS的支持票。他们的 react 非常全面。我将其粘贴在下面

感谢您就此问题与我们联系。

不幸的是，DynamoDB的数据管道导出/导入作业不支持DynamoDB的新按需模式[1]。

使用按需容量的表没有为读取和写入单位定义的容量。在计算管道的吞吐量时，数据管道依赖于此定义的容量。

例如，如果您有100个RCU(读取容量单位)并且管道吞吐量为0.25(25％)，则有效管道吞吐量将为每秒25个读取单位(100 * 0.25)。
但是，在按需容量的情况下，RCU和WCU(写入容量单位)反射(reflect)为0。无论管道吞吐量值如何，计算出的有效吞吐量均为0。

当有效吞吐量小于1时，管道将不执行。

您是否需要将DynamoDB表导出到S3？

如果您仅将这些表导出用于备份，则建议使用DynamoDB的按需备份和还原功能(与按需容量类似的名称，容易混淆)[2]。

请注意，按需备份不会影响表的吞吐量，并且会在几秒钟内完成。您只需支付与备份相关的S3存储成本。
但是，客户无法直接访问这些表备份，只能将其还原到源表。如果您希望对备份数据执行分析或将数据导入其他系统，帐户或表，则此备份方法不适合。

如果您需要使用数据管道来导出DynamoDB数据，那么前进的唯一方法是将表设置为Provisioned Capacity模式。

您可以手动执行此操作，也可以使用AWS CLI命令[3]将其作为事件包含在管道本身中。

例如(按需也称为按请求付费模式):

$ aws dynamodb update-table --table-name myTable --billing-mode PROVISIONED --provisioned-throughput ReadCapacityUnits=100,WriteCapacityUnits=100

--

$ aws dynamodb update-table --table-name myTable --billing-mode PAY_PER_REQUEST

请注意，在禁用按需容量模式后，您需要等待24小时才能再次启用它。

===引用链接===

[1] DynamoDB按需容量(另请参阅有关不支持的服务/工具的注释): https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.ReadWriteCapacityMode.html#HowItWorks.OnDemand

[2] DynamoDB按需备份和还原: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/BackupRestore.html

[3] DynamoDB“更新表”的AWS CLI引用: https://docs.aws.amazon.com/cli/latest/reference/dynamodb/update-table.html