MongoDB集群搭建之sharding
1 集群架构介绍
1.1 sharding集群架构
- shard：每个分片包含分片数据的子集。每个分片都可以部署为副本集（replica set）。可以分片，不分片的数据存于主分片服务器上。部署为3成员副本集。
- mongos：mongos充当查询路由器，提供客户端应用程序和分片集群之间的接口。可以部署多个mongos路由器。部署1个或者多个mongos。
- config servers：配置服务器存储群集的元数据和配置设置。从MongoDB 3.4开始，必须将配置服务器部署为3成员副本集。
注意：应用程序或者客户端必须要连接mongos才能与集群的数据进行交互，永远不应连接到单个分片以执行读取或写入操作。
1.2 shard的replica set的架构
1.3 config servers的replica set的架构
2 分片策略
2.1 散列分片
- 使用散列索引在共享集群中分区数据。散列索引计算单个字段的哈希值作为索引值; 此值用作分片键。
- 使用散列索引解析查询时，MongoDB会自动计算哈希值。应用程序也不会需要计算哈希值。
- 基于散列值的数据分布有助于更均匀的数据分布，尤其是在分片键单调变化的数据集中。
2.2 范围分片
- 基于分片键值将数据分成范围。然后根据分片键值为每个块分配一个范围。
- mongos可以将操作仅路由到包含所需数据的分片。
- 分片键的规划很重要，可能导致数据不能均匀分布。
3 部署
3.1 环境说明
| 服务器名称 | IP地址 | 操作系统版本 | MongoDB版本 | 配置服务器(Config Server)端口 | 分片服务器1(Shard Server 1） | 分片服务器2(Shard Server 2) | 分片服务器3(Shard Server 3) | 功能 |
|---|---|---|---|---|---|---|---|---|
| mongo1.example.com | 192.168.200.1 | Centos7.5 | 4.0 | 27027（Primary） | 27017（Primary） | 27018（Arbiter） | 27019（Secondary） | 配置服务器和分片服务器 |
| mongo2.example.com | 192.168.200.2 | Centos7.5 | 4.0 | 27027（Secondary） | 27017（Secondary） | 27018（Primary） | 27019（Arbiter） | 配置服务器和分片服务器 |
| mongo3.example.com | 192.168.200.3 | Centos7.5 | 4.0 | 27027（Secondary） | 27017（Arbiter） | 27018（Secondary） | 27019（Primary） | 配置服务器和分片服务器 |
| mongo4.example.com | 192.168.200.4 | Centos7.5 | 4.0 | mongos的端口：27017 | mongos(用于客户端连接) |
注意：官方推荐配置中使用逻辑DNS，所以该文档中，将服务器名称和IP地址的DNS映射关系写入到各服务器的/etc/hosts文件中。
3.2 部署MongoDB
环境中4台服务器的MongoDB的安装部署，详见：MongoDB安装
在服务器上创建环境所需目录：
mkdir -p /data/mongodb/data/{configServer,shard1,shard2,shard3}
mkdir -p /data/mongodb/{log,pid}
3.3 创建配置服务器（Config Server）的 Replica Set（副本集）
3台服务器上配置文件内容: /data/mongodb/configServer.conf
mongo1.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/configServer.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/configServer"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/configServer.pid"
net:
bindIp: mongo1.example.com
port: 27027
replication:
replSetName: cs0
sharding:
clusterRole: configsvr
mongo2.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/configServer.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/configServer"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/configServer.pid"
net:
bindIp: mongo2.example.com
port: 27027
replication:
replSetName: cs0
sharding:
clusterRole: configsvr
mongo3.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/configServer.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/configServer"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/configServer.pid"
net:
bindIp: mongo3.example.com
port: 27027
replication:
replSetName: cs0
sharding:
clusterRole: configsvr
启动三台服务器Config Server，进入到bin目录下，分别执行：
./mongod -f /data/mongodb/configServer.conf
连接到其中一个Config Server
./mongo --host mongo1.example.com --port 27027
连接成功的结果：
MongoDB shell version v4.0.10
connecting to: mongodb://mongo1.example.com:27027/?gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("1a4d4252-11d0-40bb-90da-f144692be88d") }
MongoDB server version: 4.0.10
Server has startup warnings:
2020-06-14T14:28:56.013+0800 I CONTROL [initandlisten]
2020-06-14T14:28:56.013+0800 I CONTROL [initandlisten] ** WARNING: Access control is not enabled for the database.
2020-06-14T14:28:56.013+0800 I CONTROL [initandlisten] ** Read and write access to data and configuration is unrestricted.
2020-06-14T14:28:56.013+0800 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2020-06-14T14:28:56.013+0800 I CONTROL [initandlisten]
2020-06-14T14:28:56.013+0800 I CONTROL [initandlisten]
2020-06-14T14:28:56.013+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2020-06-14T14:28:56.013+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'
2020-06-14T14:28:56.014+0800 I CONTROL [initandlisten]
2020-06-14T14:28:56.014+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2020-06-14T14:28:56.014+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'
2020-06-14T14:28:56.014+0800 I CONTROL [initandlisten]
>
配置Replica Set
>rs.initiate(
{
_id: "cs0",
configsvr: true,
members: [
{ _id : 0, host : "mongo1.example.com:27027" },
{ _id : 1, host : "mongo2.example.com:27027" },
{ _id : 2, host : "mongo3.example.com:27027" }
]
}
)
执行结果：
{
"ok" : 1,
"operationTime" : Timestamp(1592116308, 1),
"$gleStats" : {
"lastOpTime" : Timestamp(1592116308, 1),
"electionId" : ObjectId("000000000000000000000000")
},
"lastCommittedOpTime" : Timestamp(0, 0),
"$clusterTime" : {
"clusterTime" : Timestamp(1592116308, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
查看Replica Set的状态
cs0:PRIMARY> rs.status()
结果: 可以看出三个服务器：1个Primary，2个Secondary
{
"set" : "cs0",
"date" : ISODate("2020-06-14T06:33:31.348Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"configsvr" : true,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1590494006, 1),
"t" : NumberLong(1)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1590494006, 1),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1590494006, 1),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1590494006, 1),
"t" : NumberLong(1)
}
},
"lastStableCheckpointTimestamp" : Timestamp(1590493976, 1),
"members" : [
{
"_id" : 0,
"name" : "mongo1.example.com:27027",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 277,
"optime" : {
"ts" : Timestamp(1590494006, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2020-06-14T06:33:26Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1590493919, 1),
"electionDate" : ISODate("2020-06-14T06:31:59Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 1,
"name" : "mongo2.example.com:27027",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 102,
"optime" : {
"ts" : Timestamp(1590494006, 1),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1590494006, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2020-06-14T06:33:26Z"),
"optimeDurableDate" : ISODate("2020-06-14T06:33:26Z"),
"lastHeartbeat" : ISODate("2020-06-14T06:33:29.385Z"),
"lastHeartbeatRecv" : ISODate("2020-06-14T06:33:29.988Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "mongo1.example.com:27027",
"syncSourceHost" : "mongo1.example.com:27027",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 1
},
{
"_id" : 2,
"name" : "mongo3.example.com:27027",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 102,
"optime" : {
"ts" : Timestamp(1590494006, 1),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1590494006, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2020-06-14T06:33:26Z"),
"optimeDurableDate" : ISODate("2020-06-14T06:33:26Z"),
"lastHeartbeat" : ISODate("2020-06-14T06:33:29.384Z"),
"lastHeartbeatRecv" : ISODate("2020-06-14T06:33:29.868Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "mongo1.example.com:27027",
"syncSourceHost" : "mongo1.example.com:27027",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 1
}
],
"ok" : 1,
"operationTime" : Timestamp(1590494006, 1),
"$gleStats" : {
"lastOpTime" : Timestamp(1590493908, 1),
"electionId" : ObjectId("7fffffff0000000000000001")
},
"lastCommittedOpTime" : Timestamp(1590494006, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1590494006, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
创建管理用户
>use admin
>db.createUser(
{
user: "myAdmin",
pwd: "qwe123",
roles: [{ role: "userAdminAnyDatabase", db: "admin" },"readWriteAnyDatabase"]
}
)
开启Config Server的登录验证和内部验证
使用Keyfiles进行内部认证，在其中一台服务器上创建Keyfiles
[[email protected] ~]# openssl rand -base64 756 > /data/mongodb/keyfile
[[email protected] ~]# chmod 400 /data/mongodb/keyfile
将这个keyfile文件分发到其它的三台服务器上，并保证权限400
在/data/mongodb/configServer.conf 配置文件中开启认证：
security:
keyFile: "/data/mongodb/keyfile"
clusterAuthMode: "keyFile"
authorization: "enabled"
然后依次关闭2个Secondary，在关闭 Primary
./mongod -f /data/mongodb/configServer.conf --shutdown
依次开启Primary和两个Secondary
./mongod -f /data/mongodb/configServer.conf
使用用户密码登录mongo
mongo --host mongo1.example.com --port 27027 -u myAdmin --authenticationDatabase "admin" -p 'qwe123'
注意：由于刚创建用户的时候没有给该用户管理集群的权限，所有此时登录后，能查看所有数据库，但是不能查看集群的状态信息。
cs0:PRIMARY> rs.status()
{
"operationTime" : Timestamp(1590495861, 1),
"ok" : 0,
"errmsg" : "not authorized on admin to execute command { replSetGetStatus: 1.0, lsid: { id: UUID(\"59dd4dc0-b34f-43b9-a341-a2f43ec1dcfa\") }, $clusterTime: { clusterTime: Timestamp(1560495849, 1), signature: { hash: BinData(0, A51371EC5AA54BB1B05ED9342BFBF03CBD87F2D9), keyId: 6702270356301807629 } }, $db: \"admin\" }",
"code" : 13,
"codeName" : "Unauthorized",
"$gleStats" : {
"lastOpTime" : Timestamp(0, 0),
"electionId" : ObjectId("7fffffff0000000000000002")
},
"lastCommittedOpTime" : Timestamp(1590495861, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1590495861, 1),
"signature" : {
"hash" : BinData(0,"3UkTpXxyU8WI1TyS+u5vgewueGA="),
"keyId" : NumberLong("6702270356301807629")
}
}
}
cs0:PRIMARY> show dbs
admin 0.000GB
config 0.000GB
local 0.000GB
赋值该用户具有集群的管理权限
cs0:PRIMARY> use admin
cs0:PRIMARY> db.system.users.find() #查看当前的用户信息
cs0:PRIMARY> db.grantRolesToUser("myAdmin", ["clusterAdmin"])
查看集群信息
cs0:PRIMARY> rs.status()
{
"set" : "cs0",
"date" : ISODate("2020-06-14T07:18:20.223Z"),
"myState" : 1,
"term" : NumberLong(2),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"configsvr" : true,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1590496690, 1),
"t" : NumberLong(2)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1590496690, 1),
"t" : NumberLong(2)
},
"appliedOpTime" : {
"ts" : Timestamp(1590496690, 1),
"t" : NumberLong(2)
},
"durableOpTime" : {
"ts" : Timestamp(1590496690, 1),
"t" : NumberLong(2)
}
},
"lastStableCheckpointTimestamp" : Timestamp(1590496652, 1),
"members" : [
{
"_id" : 0,
"name" : "mongo1.example.com:27027",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 1123,
"optime" : {
"ts" : Timestamp(1590496690, 1),
"t" : NumberLong(2)
},
"optimeDate" : ISODate("2020-06-14T07:18:10Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "",
"electionTime" : Timestamp(1590495590, 1),
"electionDate" : ISODate("2020-06-14T06:59:50Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 1,
"name" : "mongo2.example.com:27027",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1113,
"optime" : {
"ts" : Timestamp(1590496690, 1),
"t" : NumberLong(2)
},
"optimeDurable" : {
"ts" : Timestamp(1590496690, 1),
"t" : NumberLong(2)
},
"optimeDate" : ISODate("2020-06-14T07:18:10Z"),
"optimeDurableDate" : ISODate("2020-06-14T07:18:10Z"),
"lastHeartbeat" : ISODate("2020-06-14T07:18:18.974Z"),
"lastHeartbeatRecv" : ISODate("2020-06-14T07:18:19.142Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "mongo1.example.com:27027",
"syncSourceHost" : "mongo1.example.com:27027",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 1
},
{
"_id" : 2,
"name" : "mongo3.example.com:27027",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1107,
"optime" : {
"ts" : Timestamp(1590496690, 1),
"t" : NumberLong(2)
},
"optimeDurable" : {
"ts" : Timestamp(1590496690, 1),
"t" : NumberLong(2)
},
"optimeDate" : ISODate("2020-06-14T07:18:10Z"),
"optimeDurableDate" : ISODate("2020-06-14T07:18:10Z"),
"lastHeartbeat" : ISODate("2020-06-14T07:18:18.999Z"),
"lastHeartbeatRecv" : ISODate("2020-06-14T07:18:18.998Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "mongo2.example.com:27027",
"syncSourceHost" : "mongo2.example.com:27027",
"syncSourceId" : 1,
"infoMessage" : "",
"configVersion" : 1
}
],
"ok" : 1,
"operationTime" : Timestamp(1590496690, 1),
"$gleStats" : {
"lastOpTime" : {
"ts" : Timestamp(1590496631, 1),
"t" : NumberLong(2)
},
"electionId" : ObjectId("7fffffff0000000000000002")
},
"lastCommittedOpTime" : Timestamp(1590496690, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1590496690, 1),
"signature" : {
"hash" : BinData(0,"lHiVw7WeO81npTi2IMW16reAN84="),
"keyId" : NumberLong("6702270356301807629")
}
}
}
3.4 部署分片服务器1（Shard1）以及Replica Set（副本集）
3台服务器上配置文件内容: /data/mongodb/shard1.conf
mongo1.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/shard1.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/shard1"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/shard1.pid"
net:
bindIp: mongo1.example.com
port: 27017
replication:
replSetName: "shard1"
sharding:
clusterRole: shardsvr
mongo2.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/shard1.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/shard1"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/shard1.pid"
net:
bindIp: mongo2.example.com
port: 27017
replication:
replSetName: "shard1"
sharding:
clusterRole: shardsvr
mongo3.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/shard1.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/shard1"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/shard1.pid"
net:
bindIp: mongo3.example.com
port: 27017
replication:
replSetName: "shard1"
sharding:
clusterRole: shardsvr
开启三台服务器上Shard
./mongod -f /data/mongodb/shard1.conf
连接Primary服务器的Shard的副本集
./mongo --host mongo1.example.com --port 27017
结果：
MongoDB shell version v4.0.10
connecting to: mongodb://mongo1.example.net:27017/?gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("91e76384-cdae-411f-ab88-b7a8bd4555d1") }
MongoDB server version: 4.0.10
Server has startup warnings:
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten]
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten] ** WARNING: Access control is not enabled for the database.
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten] ** Read and write access to data and configuration is unrestricted.
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten]
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten]
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten]
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'
2020-06-14T15:32:39.243+0800 I CONTROL [initandlisten]
>
配置Replica Set
> rs.initiate(
{
_id : "shard1",
members: [
{ _id : 0, host : "mongo1.example.com:27017",priority:2 },
{ _id : 1, host : "mongo2.example.com:27017",priority:1 },
{ _id : 2, host : "mongo3.example.com:27017",arbiterOnly:true }
]
}
)
注意：优先级priority的值越大，越容易选举成为Primary
查看Replica Set的状态：
shard1:PRIMARY> rs.status()
{
"set" : "shard1",
"date" : ISODate("2020-06-20T01:33:21.809Z"),
"myState" : 1,
"term" : NumberLong(2),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1590994393, 1),
"t" : NumberLong(2)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1590994393, 1),
"t" : NumberLong(2)
},
"appliedOpTime" : {
"ts" : Timestamp(1590994393, 1),
"t" : NumberLong(2)
},
"durableOpTime" : {
"ts" : Timestamp(1590994393, 1),
"t" : NumberLong(2)
}
},
"lastStableCheckpointTimestamp" : Timestamp(1590994373, 1),
"members" : [
{
"_id" : 0,
"name" : "mongo1.example.net:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 43,
"optime" : {
"ts" : Timestamp(1590994393, 1),
"t" : NumberLong(2)
},
"optimeDate" : ISODate("2020-06-20T01:33:13Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1590994371, 1),
"electionDate" : ISODate("2020-06-20T01:32:51Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 1,
"name" : "mongo2.example.com:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 36,
"optime" : {
"ts" : Timestamp(1590994393, 1),
"t" : NumberLong(2)
},
"optimeDurable" : {
"ts" : Timestamp(1590994393, 1),
"t" : NumberLong(2)
},
"optimeDate" : ISODate("2020-06-20T01:33:13Z"),
"optimeDurableDate" : ISODate("2020-06-20T01:33:13Z"),
"lastHeartbeat" : ISODate("2020-06-20T01:33:19.841Z"),
"lastHeartbeatRecv" : ISODate("2020-06-20T01:33:21.164Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "mongo1.example.com:27017",
"syncSourceHost" : "mongo1.example.com:27017",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 1
},
{
"_id" : 2,
"name" : "mongo3.example.com:27017",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER",
"uptime" : 32,
"lastHeartbeat" : ISODate("2020-06-20T01:33:19.838Z"),
"lastHeartbeatRecv" : ISODate("2020-06-20T01:33:20.694Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "",
"configVersion" : 1
}
],
"ok" : 1
}
上面的结果: 可以看出三个服务器：1个Primary，1个Secondary，1一个Arbiter
创建管理用户
> use admin
> db.createUser(
{
user: "myAdmin",
pwd: "qwe123",
roles: [{ role: "userAdminAnyDatabase", db: "admin" },"readWriteAnyDatabase","clusterAdmin"]
}
)
开启Shard1的登录验证和内部验证
security:
keyFile: "/data/mongodb/keyfile"
clusterAuthMode: "keyFile"
authorization: "enabled"
然后依次关闭Arbiter、Secondary、Primary
./mongod -f /data/mongodb/shard1.conf --shutdown
依次开启Primary和两个Secondary
./mongod -f /data/mongodb/shard1.conf
使用用户密码登录mongo
mongo --host mongo1.example.com --port 27017 -u myAdmin --authenticationDatabase "admin" -p 'qwe123'
3.5 部署分片服务器2（Shard2）以及Replica Set（副本集）
3台服务器上配置文件内容: /data/mongodb/shard2.conf
mongo1.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/shard2.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/shard2"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/shard2.pid"
net:
bindIp: mongo1.example.com
port: 27018
replication:
replSetName: "shard2"
sharding:
clusterRole: shardsvr
mongo2.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/shard2.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/shard2"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/shard2.pid"
net:
bindIp: mongo2.example.com
port: 27018
replication:
replSetName: "shard2"
sharding:
clusterRole: shardsvr
mongo3.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/shard2.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/shard2"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/shard2.pid"
net:
bindIp: mongo3.example.com
port: 27018
replication:
replSetName: "shard2"
sharding:
clusterRole: shardsvr
开启三台服务器上Shard
./mongod -f /data/mongodb/shard2.conf
连接Primary服务器的Shard的副本集
./mongo --host mongo2.example.com --port 27018
配置Replica Set（注意：三个服务器的角色发生了改变）
> rs.initiate(
{
_id : "shard2",
members: [
{ _id : 0, host : "mongo1.example.com:27018",arbiterOnly:true },
{ _id : 1, host : "mongo2.example.com:27018",priority:2 },
{ _id : 2, host : "mongo3.example.com:27018",priority:1 }
]
}
)
查看Replica Set的状态：
shard2:PRIMARY> rs.status()
{
"set" : "shard2",
"date" : ISODate("2020-06-20T01:59:08.996Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1590995943, 1),
"t" : NumberLong(1)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1560995943, 1),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1590995943, 1),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1590995943, 1),
"t" : NumberLong(1)
}
},
"lastStableCheckpointTimestamp" : Timestamp(1590995913, 1),
"members" : [
{
"_id" : 0,
"name" : "mongo1.example.com:27018",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER",
"uptime" : 107,
"lastHeartbeat" : ISODate("2020-06-20T01:59:08.221Z"),
"lastHeartbeatRecv" : ISODate("2020-06-20T01:59:07.496Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "",
"configVersion" : 1
},
{
"_id" : 1,
"name" : "mongo2.example.com:27018",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 412,
"optime" : {
"ts" : Timestamp(1590995943, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2020-06-20T01:59:03Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1590995852, 1),
"electionDate" : ISODate("2020-06-20T01:57:32Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 2,
"name" : "mongo3.example.com:27018",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 107,
"optime" : {
"ts" : Timestamp(1590995943, 1),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1590995943, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2020-06-20T01:59:03Z"),
"optimeDurableDate" : ISODate("2020-06-20T01:59:03Z"),
"lastHeartbeat" : ISODate("2020-06-20T01:59:08.220Z"),
"lastHeartbeatRecv" : ISODate("2020-06-20T01:59:08.716Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "mongo2.example.com:27018",
"syncSourceHost" : "mongo2.example.com:27018",
"syncSourceId" : 1,
"infoMessage" : "",
"configVersion" : 1
}
],
"ok" : 1,
"operationTime" : Timestamp(1590995943, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1590995943, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
结果: 可以看出三个服务器：1个Primary，1个Secondary，1一个Arbiter
配置登录认证的用户请按照 Shard1 的步骤
3.6 部署分片服务器3（Shard3）以及Replica Set（副本集）
3台服务器上配置文件内容: /data/mongodb/shard3.conf
mongo1.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/shard3.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/shard3"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/shard3.pid"
net:
bindIp: mongo1.example.com
port: 27019
replication:
replSetName: "shard3"
sharding:
clusterRole: shardsvr
mongo2.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/shard3.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/shard3"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/shard3.pid"
net:
bindIp: mongo2.example.com
port: 27019
replication:
replSetName: "shard3"
sharding:
clusterRole: shardsvr
mongo3.example.com服务器上
systemLog:
destination: file
path: "/data/mongodb/log/shard3.log"
logAppend: true
storage:
dbPath: "/data/mongodb/data/shard3"
journal:
enabled: true
wiredTiger:
engineConfig:
cacheSizeGB: 2
processManagement:
fork: true
pidFilePath: "/data/mongodb/pid/shard3.pid"
net:
bindIp: mongo3.example.com
port: 27019
replication:
replSetName: "shard3"
sharding:
clusterRole: shardsvr
开启三台服务器上Shard
./mongod -f /data/mongodb/shard3.conf
连接Primary服务器的Shard的副本集
./mongo --host mongo3.example.com --port 27019
配置Replica Set（注意：三个服务器的角色发生了改变）
> rs.initiate(
{
_id : "shard3",
members: [
{ _id : 0, host : "mongo1.example.com:27019",priority:1 },
{ _id : 1, host : "mongo2.example.com:27019",arbiterOnly:true },
{ _id : 2, host : "mongo3.example.com:27019",priority:2 }
]
}
)
查看Replica Set的状态：
shard3:PRIMARY> rs.status()
{
"set" : "shard3",
"date" : ISODate("2020-06-20T02:21:56.990Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1590997312, 2),
"t" : NumberLong(1)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1590997312, 2),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1590997312, 2),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1590997312, 2),
"t" : NumberLong(1)
}
},
"lastStableCheckpointTimestamp" : Timestamp(1590997312, 1),
"members" : [
{
"_id" : 0,
"name" : "mongo1.example.com:27019",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 17,
"optime" : {
"ts" : Timestamp(1590997312, 2),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1590997312, 2),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2020-06-20T02:21:52Z"),
"optimeDurableDate" : ISODate("2020-06-20T02:21:52Z"),
"lastHeartbeat" : ISODate("2020-06-20T02:21:56.160Z"),
"lastHeartbeatRecv" : ISODate("2020-06-20T02:21:55.155Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "mongo3.example.com:27019",
"syncSourceHost" : "mongo3.example.com:27019",
"syncSourceId" : 2,
"infoMessage" : "",
"configVersion" : 1
},
{
"_id" : 1,
"name" : "mongo2.example.com:27019",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER",
"uptime" : 17,
"lastHeartbeat" : ISODate("2020-06-20T02:21:56.159Z"),
"lastHeartbeatRecv" : ISODate("2020-06-20T02:21:55.021Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "",
"configVersion" : 1
},
{
"_id" : 2,
"name" : "mongo3.example.com:27019",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 45,
"optime" : {
"ts" : Timestamp(1590997312, 2),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2020-06-20T02:21:52Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1590997310, 1),
"electionDate" : ISODate("2020-06-20T02:21:50Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
}
],
"ok" : 1,
"operationTime" : Timestamp(1590997312, 2),
"$clusterTime" : {
"clusterTime" : Timestamp(1590997312, 2),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
结果: 可以看出三个服务器：1个Primary，1个Secondary，1一个Arbiter
配置登录认证的用户请按照 Shard1 的步骤
3.7 配置mongos服务器去连接分片集群
mongos.example.com 服务器上mongos的配置文件 /data/mongodb/mongos.conf
systemLog:
destination: file
path: "/data/mongodb/log/mongos.log"
logAppend: true
processManagement:
fork: true
net:
port: 27017
bindIp: mongos.example.com
sharding:
configDB: "cs0/mongo1.example.com:27027,mongo2.example.com:27027,mongo3.example.com:27027"
security:
keyFile: "/data/mongodb/keyfile"
clusterAuthMode: "keyFile"
启动mongos服务
./mongos -f /data/mongodb/mongos.conf
连接mongos
./mongo --host mongos.example.com --port 27017 -u myAdmin --authenticationDatabase "admin" -p 'qwe123'
查看当前集群结果：
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("5d0af6ed4fa51757cd032108")
}
shards:
active mongoses:
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
No recent migrations
databases:
{ "_id" : "config", "primary" : "config", "partitioned" : true }
在集群中先加入Shard1、Shard2，剩余Shard3我们在插入数据有在进行加入（模拟实现扩容）。
mongos>sh.addShard("shard1/mongo1.example.com:27017,mongo2.example.com:27017,mongo3.example.com:27017")
mongos>sh.addShard("shard2/mongo1.example.com:27018,mongo2.example.com:27018,mongo3.example.com:27018")
执行后查看集群状态：
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("5d0af6ed4fa51757cd032108")
}
shards:
{ "_id" : "shard1", "host" : "shard1/mongo1.example.com:27017,mongo2.example.com:27017", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/mongo2.example.com:27018,mongo3.example.com:27018", "state" : 1 }
active mongoses:
"4.0.10" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
No recent migrations
databases:
{ "_id" : "config", "primary" : "config", "partitioned" : true }
4 测试
先看下分片chunk的默认大小（64M）：
mongos> use config
switched to db config
mongos> db.settings.find()
{ "_id" : "chunksize", "value" : 64 }
为了方便测试，把分片chunk的大小设置为1M：
mongos> db.settings..save({"_id":"chunksize","value":1})
执行创建数据库，并启用分片存储：
mongos> sh.enableSharding("user_center")
创建“log”集合并分片：
mongos> sh.shardCollection("user_center.log",{"id":1})
数据库user_center中log集合使用了片键{“id”:1}，这个片键通过字段id的值进行数据分配，这就是范围分片。
查看集群状态：
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("5ef991c0e4405bff37a72c62")
}
shards:
{ "_id" : "shard1", "host" : "shard1/mongo1.wocloud.com:27017,mongo2.wocloud.com:27017", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/mongo2.wocloud.com:27018,mongo3.wocloud.com:27018", "state" : 1 }
active mongoses:
"4.0.10" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
No recent migrations
databases:
{ "_id" : "articledb", "primary" : "shard1", "partitioned" : true, "version" : { "uuid" : UUID("c55f15d5-d5f9-4fea-b5d2-a4cf53aac750"), "lastMod" : 1 } }
articledb.comment
shard key: { "_id" : "hashed" }
unique: false
balancing: true
chunks:
shard1 2
shard2 2
{ "_id" : { "$minKey" : 1 } } -->> { "_id" : NumberLong("-4611686018427387902") } on : shard1 Timestamp(1, 0)
{ "_id" : NumberLong("-4611686018427387902") } -->> { "_id" : NumberLong(0) } on : shard1 Timestamp(1, 1)
{ "_id" : NumberLong(0) } -->> { "_id" : NumberLong("4611686018427387902") } on : shard2 Timestamp(1, 2)
{ "_id" : NumberLong("4611686018427387902") } -->> { "_id" : { "$maxKey" : 1 } } on : shard2 Timestamp(1, 3)
{ "_id" : "config", "primary" : "config", "partitioned" : true }
config.system.sessions
shard key: { "_id" : 1 }
unique: false
balancing: true
chunks:
shard1 1
{ "_id" : { "$minKey" : 1 } } -->> { "_id" : { "$maxKey" : 1 } } on : shard1 Timestamp(1, 0)
{ "_id" : "user_center", "primary" : "shard2", "partitioned" : true, "version" : { "uuid" : UUID("badbc29b-1c41-42ca-b06c-7803c960076e"), "lastMod" : 1 } }
user_center.log
shard key: { "id" : 1 }
unique: false
balancing: true
chunks:
shard1 1
{ "id" : { "$minKey" : 1 } }-->> { "id" : { "$maxKey" : 1 } } on : shard2 Timestamp(1, 0)
批量插入数据：
mongos> use user_cent
mongos> for(var i=1;i<50000;i++) {db.log.save({"id":i,"message":"message"+i});}
执行如下命令：
mongos> db.log.stats()
分片不均匀，这是shard key的策略造成的，改变分片策略：
mongos> db.log.drop()
mongos> sh.shardCollection("user_center.log",{"id":"hashed"})
mongos> for(var i=1;i<50000;i++) {db.log.save({"id":i,"message":"message"+i});}
mongos> db.log.stats()
这就基本保持了数据的均衡。
再执行如下命令：
mongos> sh.status()
得到集群状态：
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("5ef991c0e4405bff37a72c62")
}
shards:
{ "_id" : "shard1", "host" : "shard1/mongo1.wocloud.com:27017,mongo2.wocloud.com:27017", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/mongo2.wocloud.com:27018,mongo3.wocloud.com:27018", "state" : 1 }
active mongoses:
"4.0.10" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
No recent migrations
databases:
{ "_id" : "articledb", "primary" : "shard1", "partitioned" : true, "version" : { "uuid" : UUID("c55f15d5-d5f9-4fea-b5d2-a4cf53aac750"), "lastMod" : 1 } }
articledb.comment
shard key: { "_id" : "hashed" }
unique: false
balancing: true
chunks:
shard1 2
shard2 2
{ "_id" : { "$minKey" : 1 } } -->> { "_id" : NumberLong("-4611686018427387902") } on : shard1 Timestamp(1, 0)
{ "_id" : NumberLong("-4611686018427387902") } -->> { "_id" : NumberLong(0) } on : shard1 Timestamp(1, 1)
{ "_id" : NumberLong(0) } -->> { "_id" : NumberLong("4611686018427387902") } on : shard2 Timestamp(1, 2)
{ "_id" : NumberLong("4611686018427387902") } -->> { "_id" : { "$maxKey" : 1 } } on : shard2 Timestamp(1, 3)
{ "_id" : "config", "primary" : "config", "partitioned" : true }
config.system.sessions
shard key: { "_id" : 1 }
unique: false
balancing: true
chunks:
shard1 1
{ "_id" : { "$minKey" : 1 } } -->> { "_id" : { "$maxKey" : 1 } } on : shard1 Timestamp(1, 0)
{ "_id" : "user_center", "primary" : "shard2", "partitioned" : true, "version" : { "uuid" : UUID("badbc29b-1c41-42ca-b06c-7803c960076e"), "lastMod" : 1 } }
user_center.log
shard key: { "id" : "hashed" }
unique: false
balancing: true
chunks:
shard1 2
shard2 2
{ "id" : { "$minKey" : 1 } } -->> { "id" : NumberLong("-6148914691236517204") } on : shard1 Timestamp(1, 0)
{ "id" : NumberLong("-6148914691236517204") } -->> { "id" : NumberLong("-3074457345618258602") } on : shard1 Timestamp(1, 1)
{ "id" : NumberLong("-3074457345618258602") } -->> { "id" : NumberLong(0) } on : shard2 Timestamp(1, 2)
{ "id" : NumberLong(0) } -->> { "id" : NumberLong("3074457345618258602") } -->> { "id" : NumberLong("6148914691236517204") } -->> { "id" : { "$maxKey" : 1 } } on : shard2 Timestamp(1, 5)
可以看出，数据分别再Shard1、Shard2分片上。
将Shard3分片也加入到集群中来:
mongos> sh.addShard("shard3/mongo1.example.com:27019,mongo2.example.com:27019,mongo3.example.com:27019")
再查看集群的状态：
mongos> sh.status()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"minCompatibleVersion" : 5,
"currentVersion" : 6,
"clusterId" : ObjectId("5ef991c0e4405bff37a72c62")
}
shards:
{ "_id" : "shard1", "host" : "shard1/mongo1.wocloud.com:27017,mongo2.wocloud.com:27017", "state" : 1 }
{ "_id" : "shard2", "host" : "shard2/mongo2.wocloud.com:27018,mongo3.wocloud.com:27018", "state" : 1 }
{ "_id" : "shard3", "host" : "shard3/mongo1.wocloud.com:27019,mongo3.wocloud.com:27019", "state" : 1 }
active mongoses:
"4.0.10" : 1
autosplit:
Currently enabled: yes
balancer:
Currently enabled: yes
Currently running: no
Failed balancer rounds in last 5 attempts: 0
Migration Results for the last 24 hours:
4 : Success
databases:
{ "_id" : "articledb", "primary" : "shard1", "partitioned" : true, "version" : { "uuid" : UUID("c55f15d5-d5f9-4fea-b5d2-a4cf53aac750"), "lastMod" : 1 } }
articledb.comment
shard key: { "_id" : "hashed" }
unique: false
balancing: true
chunks:
shard1 2
shard2 2
{ "_id" : { "$minKey" : 1 } } -->> { "_id" : NumberLong("-4611686018427387902") } on : shard1 Timestamp(1, 0)
{ "_id" : NumberLong("-4611686018427387902") } -->> { "_id" : NumberLong(0) } on : shard1 Timestamp(1, 1)
{ "_id" : NumberLong(0) } -->> { "_id" : NumberLong("4611686018427387902") } on : shard2 Timestamp(1, 2)
{ "_id" : NumberLong("4611686018427387902") } -->> { "_id" : { "$maxKey" : 1 } } on : shard2 Timestamp(1, 3)
{ "_id" : "config", "primary" : "config", "partitioned" : true }
config.system.sessions
shard key: { "_id" : 1 }
unique: false
balancing: true
chunks:
shard1 1
{ "_id" : { "$minKey" : 1 } } -->> { "_id" : { "$maxKey" : 1 } } on : shard1 Timestamp(1, 0)
{ "_id" : "user_center", "primary" : "shard2", "partitioned" : true, "version" : { "uuid" : UUID("badbc29b-1c41-42ca-b06c-7803c960076e"), "lastMod" : 1 } }
user_center.log
shard key: { "id" : "hashed" }
unique: false
balancing: true
chunks:
shard1 2
shard2 2
shard3 2
{ "id" : { "$minKey" : 1 } } -->> { "id" : NumberLong("-6148914691236517204") } on : shard1 Timestamp(1, 0)
{ "id" : NumberLong("-6148914691236517204") } -->> { "id" : NumberLong("-3074457345618258602") } on : shard1 Timestamp(1, 1)
{ "id" : NumberLong("-3074457345618258602") } -->> { "id" : NumberLong(0) } on : shard2 Timestamp(1, 2)
{ "id" : NumberLong(0) } -->> { "id" : NumberLong("3074457345618258602") } on : shard2 Timestamp(1, 3)
{ "id" : NumberLong("3074457345618258602") } -->> { "id" : NumberLong("6148914691236517204") } on : shard3 Timestamp(1, 4)
{ "id" : NumberLong("6148914691236517204") } -->> { "id" : { "$maxKey" : 1 } } on : shard3 Timestamp(1, 5)
加入后，集群的分片数据重新平衡调整，有一部分数据分布到Shard3上。
5 备份和恢复
参考：1、https://www.cnblogs.com/sz-wenbin/p/11022563.html
2、https://blog.csdn.net/hanlicun/article/details/79185089