如何在不同可用区创建极光集群数据库实例？

Question

我在 ap-southeast-2 区域（1 位写入者，2 位 reader）创建了一个包含 3 个实例的 Aurora 集群 (postgresql 11)。我注意到作者在 AZ 2b 中，但两个 reader 在同一个 AZ 中，即 2a。我怎样才能让它们均匀分布到 3 个可用区？

此集群的 cloudformation：

AuroraDBFirstInstance:
    Type: AWS::RDS::DBInstance
    Properties:
      DBInstanceClass: ${self:custom.postgresqlInstanceClass}
      Engine: aurora-postgresql
      EngineVersion: ${self:custom.postgresqlEngineVersion}
      DBClusterIdentifier: !Ref AuroraDBCluster
      PubliclyAccessible: ${self:custom.publiclyAccessible}

  AuroraDBSecondInstance:
    Type: AWS::RDS::DBInstance
    Properties:
      DBInstanceClass: ${self:custom.postgresqlInstanceClass}
      Engine: aurora-postgresql
      EngineVersion: ${self:custom.postgresqlEngineVersion}
      DBClusterIdentifier: !Ref AuroraDBCluster
      PubliclyAccessible: ${self:custom.publiclyAccessible}

  AuroraDBThirdInstance:
    Type: AWS::RDS::DBInstance
    Properties:
      DBInstanceClass: ${self:custom.postgresqlInstanceClass}
      Engine: aurora-postgresql
      EngineVersion: ${self:custom.postgresqlEngineVersion}
      DBClusterIdentifier: !Ref AuroraDBCluster
      PubliclyAccessible: ${self:custom.publiclyAccessible}

Answer 1

您可以在cloudformation中自行指定AZ。如果您不指定子网，Aurora 将从您提供的子网组中随机选择 AZ。


Type: AWS::RDS::DBInstance
Properties: 
  AllocatedStorage: String
  AllowMajorVersionUpgrade: Boolean
  AssociatedRoles: 
    - DBInstanceRole
  AutoMinorVersionUpgrade: Boolean
  AvailabilityZone: String
  BackupRetentionPeriod: Integer
  CACertificateIdentifier: String
  CharacterSetName: String
  CopyTagsToSnapshot: Boolean
  DBClusterIdentifier: String
  DBInstanceClass: String
  DBInstanceIdentifier: String
  DBName: String
  DBParameterGroupName: String
  DBSecurityGroups: 
    - String
  DBSnapshotIdentifier: String
  DBSubnetGroupName: String
  DeleteAutomatedBackups: Boolean
  DeletionProtection: Boolean
  Domain: String
  DomainIAMRoleName: String
  EnableCloudwatchLogsExports: 
    - String
  EnableIAMDatabaseAuthentication: Boolean
  EnablePerformanceInsights: Boolean
  Engine: String
  EngineVersion: String
  Iops: Integer
  KmsKeyId: String
  LicenseModel: String
  MasterUsername: String
  MasterUserPassword: String
  MaxAllocatedStorage: Integer
  MonitoringInterval: Integer
  MonitoringRoleArn: String
  MultiAZ: Boolean
  OptionGroupName: String
  PerformanceInsightsKMSKeyId: String
  PerformanceInsightsRetentionPeriod: Integer
  Port: String
  PreferredBackupWindow: String
  PreferredMaintenanceWindow: String
  ProcessorFeatures: 
    - ProcessorFeature
  PromotionTier: Integer
  PubliclyAccessible: Boolean
  SourceDBInstanceIdentifier: String
  SourceRegion: String
  StorageEncrypted: Boolean
  StorageType: String
  Tags: 
    - Tag
  Timezone: String
  UseDefaultProcessorFeatures: Boolean
  VPCSecurityGroups: 
    - String

有关每个属性的更好信息，您可以参考 cloudformation 模板文档。 https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-rds-database-instance.html

Answer 2

您可以通过 DBSubnetGroup and AvailabilityZone.

控制数据库实例的放置

下面是工作示例，用于创建 DBSubnetGroup，其中包含 us-east-1 中 3 个不同 AZ 中的 3 个子网。运行这个例子你唯一需要做的就是 将 subnet-ids 从 us-east-1a, us-east-1b,us-east-1c MyDBSubnetGroup 中的可用区：

Resources:

  MyDBSubnetGroup: 
    Properties: 
      DBSubnetGroupDescription: Subent Group in 3 AZs
      SubnetIds: 
        - subnet-82c876e5
        - subnet-21ef547d
        - subnet-a9e16487
    Type: "AWS::RDS::DBSubnetGroup"

  RDSCluster: 
    Properties: 
      DBSubnetGroupName: !Ref MyDBSubnetGroup
      Engine: aurora-postgresql
      MasterUserPassword: postgresql22332   
      MasterUsername: postgresql
    Type: "AWS::RDS::DBCluster"

  RDSDBInstance1: 
    Properties: 
      AvailabilityZone: us-east-1a
      DBClusterIdentifier: 
        Ref: RDSCluster
      DBInstanceClass: db.t3.medium
      Engine: aurora-postgresql
      PubliclyAccessible: "true"
      DeleteAutomatedBackups: true
    Type: "AWS::RDS::DBInstance"

  RDSDBInstance2: 
    Properties: 
      AvailabilityZone: us-east-1b
      DBClusterIdentifier: 
        Ref: RDSCluster
      DBInstanceClass: db.t3.medium
      Engine: aurora-postgresql
      PubliclyAccessible: "true"
      DeleteAutomatedBackups: true
    Type: "AWS::RDS::DBInstance"

  RDSDBInstance3: 
    Properties: 
      AvailabilityZone: us-east-1c
      DBClusterIdentifier: 
        Ref: RDSCluster
      DBInstanceClass: db.t3.medium
      Engine: aurora-postgresql
      PubliclyAccessible: "true"      
      DeleteAutomatedBackups: true      
    Type: "AWS::RDS::DBInstance"

如何在不同可用区创建极光集群数据库实例？

How can I create aurora cluster db instance in different available zone?

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