Deploy a Sharded Cluster部署分片集群

Connectivity连通性

Each member of a sharded cluster must be able to connect to all other members in the cluster. 分片集群的每个成员必须能够连接到集群中的所有其他成员。This includes all shards and config servers. 这包括所有分片和配置服务器。Ensure that network and security systems, including all interface and firewalls, allow these connections.确保网络和安全系统（包括所有接口和防火墙）允许这些连接。

Hostnames and Configuration主机名和配置

Security安全

This tutorial does not include the required steps for configuring Internal/Membership Authentication or Role-Based Access Control.本教程不包括配置内部/成员身份验证或基于角色的访问控制所需的步骤。

In production environments, sharded clusters should employ at minimum x.509 security for internal authentication and client access.在生产环境中，分片集群应至少采用x.509安全性进行内部身份验证和客户端访问。

Create the Config Server Replica Set创建配置服务器副本集

The following steps deploys a config server replica set.以下步骤部署配置服务器副本集。

For a production deployment, deploy a config server replica set with at least three members. 对于生产部署，部署至少包含三个成员的配置服务器副本集。For testing purposes, you can create a single-member replica set.出于测试目的，您可以创建一个单成员副本集。

For this tutorial, the config server replica set members are associated with the following hosts:对于本教程，配置服务器副本集成员与以下主机关联：

sharding:
  clusterRole: configsvr
replication:
  replSetName: <replica set name>
net:
  bindIp: localhost,<hostname(s)|ip address(es)>

mongod --config <path-to-config-file>

mongod --configsvr --replSet <replica set name> --dbpath <path> --bind_ip localhost,<hostname(s)|ip address(es)>

mongosh --host <hostname> --port <port>

rs.initiate(
  {
    _id: "myReplSet",
    configsvr: true,
    members: [
      { _id : 0, host : "cfg1.example.net:27019" },
      { _id : 1, host : "cfg2.example.net:27019" },
      { _id : 2, host : "cfg3.example.net:27019" }
    ]
  }
)

Once the config server replica set (CSRS) is initiated and up, proceed to creating the shard replica sets.一旦配置服务器副本集（CSRS）启动并启动，继续创建分片副本集。

Create the Shard Replica Sets创建分片复制集

For a production deployment, use a replica set with at least three members. 对于生产部署，请使用至少包含三个成员的副本集。For testing purposes, you can create a single-member replica set.出于测试目的，您可以创建一个单成员副本集。

For each shard, use the following steps to create the shard replica set:对于每个分片，使用以下步骤创建分片副本集：

sharding:
    clusterRole: shardsvr
replication:
    replSetName: <replSetName>
net:
    bindIp: localhost,<ip address>

mongod --config <path-to-config-file>

mongod --shardsvr --replSet <replSetname>  --dbpath <path> --bind_ip localhost,<hostname(s)|ip address(es)>

mongosh --host <hostname> --port <port>

rs.initiate(
  {
    _id : "myReplSet",
    members: [
      { _id : 0, host : "s1-mongo1.example.net:27018" },
      { _id : 1, host : "s1-mongo2.example.net:27018" },
      { _id : 2, host : "s1-mongo3.example.net:27018" }
    ]
  }
)

Start a mongos for the Sharded Cluster为分片集群启动mongos

Start a mongos using either a configuration file or a command line parameter to specify the config servers.使用配置文件或命令行参数启动mongos，以指定配置服务器。

sharding:
  configDB: <configReplSetName>/cfg1.example.net:27019,cfg2.example.net:27019
net:
  bindIp: localhost,<hostname(s)|ip address(es)>

mongos --config <path-to-config>

mongos --configdb <configReplSetName>/cfg1.example.net:27019,cfg2.example.net:27019,cfg3.example.net:27019 --bind_ip localhost,<hostname(s)|ip address(es)>

At this point, your sharded cluster consists of the mongos and the config servers. 此时，您的分片集群由mongos和配置服务器组成。You can now connect to the sharded cluster using mongosh.现在可以使用mongosh连接到分片集群。

Connect to the Sharded Cluster连接到分片集群

Connect mongosh to the mongos. 将mongosh连接到mongos。Specify the host and port on which the mongos is running:指定运行mongos的host和port：

mongosh --host <hostname> --port <port>

Once you have connected mongosh to the mongos, continue to the next procedure to add shards to the cluster.将mongosh连接到mongos后，继续下一个过程，将分片添加到集群。

Add Shards to the Cluster将分片添加到集群

In a mongosh session that is connected to the mongos, use the sh.addShard() method to add each shard to the cluster.在连接到mongos的mongosh会话中，使用sh.addShard()方法将每个分片添加到集群。

The following operation adds a single shard replica set to the cluster:以下操作将单个分片复制集添加到集群：

sh.addShard( "<replSetName>/s1-mongo1.example.net:27018,s1-mongo2.example.net:27018,s1-mongo3.example.net:27018")

Repeat these steps until the cluster includes all desired shards.重复这些步骤，直到集群包含所有所需的分片。

Enable Sharding for a Database为数据库启用分片

Before you can shard a collection, you must enable sharding for the collection's database. 在对集合进行分片之前，必须为集合的数据库启用分片。Enabling sharding for a database does not redistribute data but make it possible to shard the collections in that database.为数据库启用分片不会重新分发数据，但可以对该数据库中的集合进行分片。

From a mongosh session that is connected to the mongos, use the sh.enableSharding() method to enable sharding on the target database. 在连接到mongos的mongosh会话中，使用sh.enableSharding()方法在目标数据库上启用分片。Enabling sharding on a database makes it possible to shard collections within a database.在数据库上启用分片可以在数据库中分片集合。

sh.enableSharding("<database>")

Once you enable sharding for a database, MongoDB assigns a primary shard for that database where MongoDB stores all data in that database.一旦为数据库启用分片，MongoDB将为该数据库分配一个主分片，其中MongoDB存储该数据库中的所有数据。

Shard a Collection分片集合

To shard a collection, connect mongosh to the mongos and use the sh.shardCollection() method.要共享集合，请将mongosh连接到mongos，并使用sh.shardCollection()方法。

MongoDB provides two strategies to shard collections:MongoDB为分片集合提供了两种策略：

• Hashed sharding uses a hashed index of a single field as the shard key to partition data across your sharded cluster.散列分片使用单个字段的散列索引作为分片键，在分片集群中对数据进行分区。

  sh.shardCollection("<database>.<collection>", { <shard key field> : "hashed" } )

• Range-based sharding基于范围的分片 can use multiple fields as the shard key and divides data into contiguous ranges determined by the shard key values.可以使用多个字段作为分片键，并将数据划分为由分片键值确定的连续范围。

  sh.shardCollection("<database>.<collection>", { <shard key field> : 1, ... } )

Shard Key Considerations分片关键考虑因素

Your selection of shard key affects the efficiency of sharding, as well as your ability to take advantage of certain sharding features such as zones. 分片键的选择会影响分片的效率，以及您利用某些分片功能（如分区）的能力。To learn how to choose an effective shard key, see Choose a Shard Key.要了解如何选择有效的分片键，请参阅选择分片键。

Starting in version 4.0, mongosh provides the method convertShardKeyToHashed(). 从版本4.0开始，mongosh提供了convertShardKeyToHashed()方法。This method uses the same hashing function as the hashed index and can be used to see what the hashed value would be for a key.该方法使用与散列索引相同的散列函数，并可用于查看键的散列值。