Database Manual / Reference / Database Commands / Sharding

transitionFromDedicatedConfigServer (database command数据库命令)

Definition定义

transitionFromDedicatedConfigServer

New in version 8.0.在版本8.0中新增。

Starting in MongoDB 8.0, you can:从MongoDB 8.0开始，您可以：

  • Configure a config server to store your application data in addition to the usual sharded cluster metadata. A config server that stores application data is called a config shard.配置配置服务器以存储应用程序数据以及通常的分片集群元数据。存储应用程序数据的配置服务器称为配置分片。
  • Transition a config server between being a config shard and a dedicated config server.在配置分片和专用配置服务器之间转换配置服务器。

A cluster requires a config server, but it can be a config shard instead of a dedicated config server. Using a config shard reduces the number of nodes required and can simplify your deployment.集群需要一个配置服务器，但它可以是一个配置分片，而不是一个专用的配置服务器。使用配置分片可以减少所需的节点数量，并简化部署。

If your application has demanding availability and resiliency requirements, consider deploying a dedicated config server. A dedicated config server provides isolation, dedicated resources, and consistent performance for critical cluster operations.如果应用程序具有苛刻的可用性和弹性要求，请考虑部署专用配置服务器。专用配置服务器为关键集群操作提供隔离、专用资源和一致的性能。

The transitionFromDedicatedConfigServer command configures a dedicated config server to run as a config shard.transitionFromDedicatedConfigServer命令将专用配置服务器配置为作为配置分片运行。

Before you run transitionFromDedicatedConfigServer, connect to mongos and use the admin database.在运行transitionFromDedicatedConfigServer之前，请连接到mongos并使用admin数据库。

The sharded cluster must have featureCompatibilityVersion set to at least 8.0.分片集群必须将featureCompatibilityVersion设置为至少8.0。

Syntax语法

Command syntax:命令语法：

db.adminCommand( {
   transitionFromDedicatedConfigServer: 1
} )

Behavior行为

The transitionFromDedicatedConfigServer command adds the config server as a shard in the cluster. Internally, transitionFromDedicatedConfigServer runs the addShard command.transitionFromDedicatedConfigServer命令将配置服务器作为分片添加到集群中。在内部，transitionFromDedicatedConfigServer运行addShard命令。

You can confirm that a sharded cluster uses a config shard by using one of the following methods:您可以使用以下方法之一确认分片集群使用配置分片：

  • Run the sh.isConfigShardEnabled() method in mongosh. 在mongosh中运行sh.isConfigShardEnabled()方法。If the sh.isConfigShardEnabled() output contains enabled: true, the cluster uses a config shard. If the output contains enabled: false, the cluster does not use a config shard.如果sh.isConfigShardEnabled()输出包含enabled:true，则集群使用配置分片。如果输出包含enabled:false，则集群不使用配置分片。
  • Run the listShards command against the admin database while connected to a mongos and inspect the output for a document where _id is set to "config". 在连接到mongos时，对admin数据库运行listShards命令，并检查_id设置为"config"的文档的输出。If the listShards output does not contain a document where _id is set to "config", the cluster does not use a config shard.如果listShards输出不包含_id设置为"config"的文档，则集群不使用配置分片。

For details, see Confirm use of Config Shard.有关详细信息，请参阅确认使用Config分片。

If you must downgrade the feature compatibility version below 8.0, first run the transitionToDedicatedConfigServer command. For downgrade details, see Downgrade Feature Compatibility Version.如果必须将功能兼容性版本降级到8.0以下，请先运行transitionToDedicatedConfigServer命令。有关降级的详细信息，请参阅降级功能兼容性版本。

Access Control访问控制

If access control is enabled, the transitionFromDedicatedConfigServer command requires the transitionFromDedicatedConfigServer authorization action for the cluster:如果启用了访问控制，则transitionFromDedicatedConfigServer命令要求对群集执行transitionFromDedicatedConfigServer授权操作：

{
   resource: { cluster : true },
   actions: [ "transitionFromDedicatedConfigServer" ]
}

The clusterManager role has transitionFromDedicatedConfigServer authorization action and can be assigned to a user.clusterManager角色具有从transitionFromDedicatedConfigServer授权操作转换，可以分配给用户。

The following example assigns the clusterManager role to a user named testUser:以下示例将clusterManager角色分配给名为testUser的用户：

db.grantRolesToUser(
   "testUser",
   [ "clusterManager" ]
)

Example示例

The following example configures a dedicated config server to run as a config shard:以下示例将专用配置服务器配置为作为配置分片运行：

db.adminCommand( {
   transitionFromDedicatedConfigServer: 1
} )

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