Mongodb副本集分片集群模式环境部署

分片（sharding）是指将数据库拆分，将其分散在不同的机器上的过程。将数据分散到不同的机器上，不需要功能强大的服务器就可以存储更多的数据和处理更大的负载。基本思想就是将集合切成小块，这些块分散到若干片里，每个片只负责总数据的一部分，最后通过一个均衡器来对各个分片进行均衡（数据迁移）。通过一个名为mongos的路由进程进行操作，mongos知道数据和片的对应关系（通过配置服务器）。大部分使用场景都是解决磁盘空间的问题，对于写入有可能会变差（+++里面的说明+++），查询则尽量避免跨分片查询。使用分片的时机：

1，机器的磁盘不够用了。使用分片解决磁盘空间的问题。
2，单个mongod已经不能满足写数据的性能要求。通过分片让写压力分散到各个分片上面，使用分片服务器自身的资源。
3，想把大量数据放到内存里提高性能。和上面一样，通过分片使用分片服务器自身的资源。

MongoDB sharding Cluster（分片集群）,需要三种角色

Shard Server: mongod 实例，用于存储实际的数据块，实际生产环境中一个shard server角色可由几台机器组个一个relica set承担，防止主机单点故障;

Config Server: mongod 实例，存储了整个 Cluster Metadata，其中包括 chunk 信息。

Route Server: mongos 实例，前端路由，客户端由此接入，且让整个集群看上去像单一数据库，前端应用可以透明使用。

集群搭建服务器规划（共3个分片集群，每个集群3个副本集，另外一个3结点配置副本集，一个3结点路由副本集）：

1、安装Mongodb(3台机器都要操作，本次用的4.0.3版本)
下载地址：https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-4.0.3.tgz

解压
[mongo@mongo1 ~]$ tar -zxvf mongodb-linux-x86_64-4.0.3.tgz 
修改解压目录名
[mongo@mongo1 ~]$ mv mongodb-linux-x86_64-4.0.3 mongodb

2、创建相应集群所需目录（3台机器根据上述服务器规划表，分别操作）

[mongo@mongo1 ~]$ mkdir services
[mongo@mongo1 ~]$ mv mongodb services/
[mongo@mongo1 ~]$ mkdir -p services/shard1 services/shard1/db services/shard2 services/shard2/db services/shard3 services/shard3/db services/configsvr services/configsvr/db services/mongos

3、配置relica sets

进入到servcies目录

[mongo@mongo1 ~]$ cd services/

 在三台机器上分别先执行（1）（2）（3）（4）步，注意配置文件中bingIp属性，需不同机器不同配置

（1）配置并启动Shard1

[mongo@mongo1 services]$ vi shard1/mongod.conf 

#shard1 mongod.conf
storage:
    dbPath: /home/mongo/services/shard1/db
    journal:
        enabled: true
systemLog:
    destination: file
    logAppend: true
    path: /home/mongo/services/shard1/mongod.log
net:
    port: 27018
    bindIp: 172.16.0.192
processManagement: 
　　fork: true 
　　pidFilePath: /home/mongo/services/shard1/pid 
replication: 
　　replSetName: shard1 
sharding: 
　　clusterRole: shardsvr

启动mongod进程，查看是否成功，若不成功，可查看配置的mongod.log，根据错误日志进行配置文件修改

[mongo@mongo1 services]$ mongodb/bin/mongod -f shard1/mongod.conf 
about to fork child process, waiting until server is ready for connections.
forked process: 19834
child process started successfully, parent exiting

（2）配置并启动Shard2

[mongo@mongo1 services]$ vi shard2/mongod.conf 

#shard2 mongod.conf
storage:
    dbPath: /home/mongo/services/shard2/db
    journal:
        enabled: true
systemLog:
    destination: file
    logAppend: true
    path: /home/mongo/services/shard2/mongod.log
net:
    port: 27019
    bindIp: 127.0.0.1
processManagement:
    fork: true
    pidFilePath: /home/mongo/services/shard2/pid
replication:
    replSetName: shard2
sharding:
    clusterRole: shardsvr

启动mongod进程，查看是否成功，若不成功，可查看配置的mongod.log，根据错误日志进行配置文件修改

[mongo@mongo1 services]$ mongodb/bin/mongod -f shard2/mongod.conf 
about to fork child process, waiting until server is ready for connections.
forked process: 27144
child process started successfully, parent exiting

（3）配置并启动Shard3

[mongo@mongo1 services]$ vi shard3/mongod.conf 

#shard31 mongod.conf
storage:
    dbPath: /home/mongo/services/shard3/db
    journal:
        enabled: true
systemLog:
    destination: file
    logAppend: true
    path: /home/mongo/services/shard3/mongod.log
net:
    port: 27020
    bindIp: 127.0.0.1
processManagement:
    fork: true
    pidFilePath: /home/mongo/services/shard3/pid
replication:
    replSetName: shard3
sharding:
    clusterRole: shardsvr

 启动mongod进程

[mongo@mongo1 services]$ mongodb/bin/mongod -f shard3/mongod.conf 
about to fork child process, waiting until server is ready for connections.
forked process: 1101
child process started successfully, parent exiting

（4）配置并启动configsvr

[mongo@mongo1 services]$ vi configsvr/cfg.conf

#configsvr cfg.conf
storage:
    dbPath: /home/mongo/services/configsvr/db
    journal:
        enabled: true
systemLog:
    destination: file
    logAppend: true
    path: /home/mongo/services/configsvr/mongod.log
net:
    port: 20000
    bindIp: 127.0.0.1
processManagement:
    fork: true
    pidFilePath: /home/mongo/services/configsvr/pid
replication:
    replSetName: cfg
sharding:
    clusterRole: configsvr

 启动mongod进程

[mongo@mongo1 services]$ mongodb/bin/mongod -f configsvr/cfg.conf 
about to fork child process, waiting until server is ready for connections.
forked process: 7940
child process started successfully, parent exiting

（5）关闭防火墙或者开放防火墙上述所用端口

各种版本liunx的防火墙关闭指令不同，目前我这里使用的是CentOS7

[mongo@mongo1 services]$ systemctl stop firewalld
==== AUTHENTICATING FOR org.freedesktop.systemd1.manage-units ===
Authentication is required to manage system services or units.
Authenticating as: root
Password: 
==== AUTHENTICATION COMPLETE ===

（6）初始化Shard副本集

进入其中一个Shard1容器配置Shard1副本集

[mongo@mongo1 services]$ mongodb/bin/mongo 172.16.0.194:27018
MongoDB shell version v4.0.3
connecting to: mongodb://172.16.0.194:27018/test
Implicit session: session { "id" : UUID("d24db7a9-132f-4db4-8b20-0a082f72486d") }
MongoDB server version: 4.0.3
Server has startup warnings: 
2018-10-30T23:41:10.942+0800 I CONTROL  [initandlisten] 
2018-10-30T23:41:10.942+0800 I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
2018-10-30T23:41:10.942+0800 I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
2018-10-30T23:41:10.942+0800 I CONTROL  [initandlisten] 
2018-10-30T23:41:10.942+0800 I CONTROL  [initandlisten] 
2018-10-30T23:41:10.943+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2018-10-30T23:41:10.943+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2018-10-30T23:41:10.943+0800 I CONTROL  [initandlisten] 
2018-10-30T23:41:10.943+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2018-10-30T23:41:10.943+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2018-10-30T23:41:10.943+0800 I CONTROL  [initandlisten] 
> 
> rs.initiate({
...     "_id":"shard1",
...     "members":[
...         {
...             "_id":0,
...             "host":"172.16.0.192:27018"
...         },
...         {
...             "_id":1,
...             "host":"172.16.0.193:27018"
...         },
...         {
...             "_id":2,
...             "host":"172.16.0.194:27018"
...         }
...     ]
... })
{
        "ok" : 1,
        "operationTime" : Timestamp(1540915476, 1),
        "$clusterTime" : {
                "clusterTime" : Timestamp(1540915476, 1),
                "signature" : {
                        "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
                        "keyId" : NumberLong(0)
                }
        }
}

进入其中一个Shard2容器配置Shard2副本集

[mongo@mongo1 services]$ mongodb/bin/mongo 172.16.0.193:27019

> rs.initiate({
...     "_id":"shard3",
...     "members":[
...         {
...             "_id":0,
...             "host":"172.16.0.192:27020"
...         },
...         {
...             "_id":1,
...             "host":"172.16.0.193:27020"
...         },
...         {
...             "_id":2,
...             "host":"172.16.0.194:27020"
...         }
...     ]
... })

进入其中一个Shard3容器配置Shard3副本集

[mongo@mongo1 services]$ mongodb/bin/mongo 172.16.0.192:27020

2018-10-30T23:32:26.519+0800 I CONTROL  [initandlisten] 
> rs.initiate({
...     "_id":"shard3",
...     "members":[
...         {
...             "_id":0,
...             "host":"172.16.0.192:27020"
...         },
...         {
...             "_id":1,
...             "host":"172.16.0.193:27020"
...         },
...         {
...             "_id":2,
...             "host":"172.16.0.194:27020"
...         }
...     ]
... })

（7）初始化Configsvr副本集

进入其中一个Configsvr容器配置Configsvr副本集

[mongo@mongo1 services]$ mongodb/bin/mongo 172.16.0.193:20000

> rs.initiate({
...     "_id":"cfg",
...     "members":[
...         {
...             "_id":0,
...             "host":"172.16.0.192:20000"
...         },
...         {
...             "_id":1,
...             "host":"172.16.0.193:20000"
...         },
...         {
...             "_id":2,
...             "host":"172.16.0.194:20000"
...         }
...     ]
... })

4、配置并启动路由进程（分别在三台机器上操作，注意bindIp的值）

[mongo@mongo1 services]$ vi mongos/mongos.conf

#mongos mongos.conf
systemLog:
    destination: file
    logAppend: true
    path: /home/mongo/services/mongos/mongos.log
net:
    port: 27017
    bindIp: 172.16.0.192
processManagement:
    fork: true
    pidFilePath: /home/mongo/services/mongos/pid
sharding:
    configDB: cfg/172.16.0.192:20000,172.16.0.193:20000,172.16.0.194:20000

启动路由进程

[mongo@mongo1 services]$ mongodb/bin/mongos -f mongos/mongos.conf
about to fork child process, waiting until server is ready for connections.
forked process: 27963
child process started successfully, parent exiting

 5、添加分片集群

（1）从3台机器中任意找一台，连接mongod

[mongo@mongo3 services]$ mongodb/bin/mongo 172.16.0.192:27017

（2）添加3个分片集群

mongos> sh.addShard("shard1/172.16.0.192:27018,172.16.0.193:27018,172.16.0.194:27018")
{
        "shardAdded" : "shard1",
        "ok" : 1,
        "operationTime" : Timestamp(1540981435, 6),
        "$clusterTime" : {
                "clusterTime" : Timestamp(1540981435, 6),
                "signature" : {
                        "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
                        "keyId" : NumberLong(0)
                }
        }
}
mongos> sh.addShard("shard2/172.16.0.192:27019,172.16.0.193:27019,172.16.0.194:27019")
{
        "shardAdded" : "shard2",
        "ok" : 1,
        "operationTime" : Timestamp(1540981449, 1),
        "$clusterTime" : {
                "clusterTime" : Timestamp(1540981449, 1),
                "signature" : {
                        "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
                        "keyId" : NumberLong(0)
                }
        }
}
mongos> sh.addShard("shard3/172.16.0.192:27020,172.16.0.193:27020,172.16.0.194:27020")
{
        "shardAdded" : "shard3",
        "ok" : 1,
        "operationTime" : Timestamp(1540981455, 1),
        "$clusterTime" : {
                "clusterTime" : Timestamp(1540981455, 1),
                "signature" : {
                        "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
                        "keyId" : NumberLong(0)
                }
        }
}

 （3）通过sh.status()检查上面配置是否正确

mongos> sh.status()
--- Sharding Status --- 
  sharding version: {
        "_id" : 1,
        "minCompatibleVersion" : 5,
        "currentVersion" : 6,
        "clusterId" : ObjectId("5bd8849513e9f7fb57277071")
  }
  shards:
        {  "_id" : "shard1",  "host" : "shard1/172.16.0.192:27018,172.16.0.193:27018,172.16.0.194:27018",  "state" : 1 }
        {  "_id" : "shard2",  "host" : "shard2/172.16.0.192:27019,172.16.0.193:27019,172.16.0.194:27019",  "state" : 1 }
        {  "_id" : "shard3",  "host" : "shard3/172.16.0.192:27020,172.16.0.193:27020,172.16.0.194:27020",  "state" : 1 }
  active mongoses:
        "4.0.3" : 3
  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 }
                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) 

mongos> 

（4）查看分片集群数据库信息

mongos> show dbs;
admin   0.000GB
config  0.001GB
mongos> db
test
mongos> use config
switched to db config
mongos> show collections
changelog
chunks
collections
lockpings
locks
migrations
mongos
shards
tags
transactions
version
mongos> 

至此，MongoDB分片集群部署成功，生产部署还需要调整一些参数，这部分内容可以通过--help查看参数详情。

  6、测试分片集群

 （1）新建数据库，且向集合中插入文档

mongos> use testShard;
switched to db testShard
mongos> db.users.insert({userid:1,username:"ChavinKing",city:"beijing"})
WriteResult({ "nInserted" : 1 })
mongos> db.users.find()
{ "_id" : ObjectId("5bd99310e1a54b9bca661075"), "userid" : 1, "username" : "ChavinKing", "city" : "beijing" }
mongos> 

（2）查看分片集群状态

mongos> sh.status();
--- Sharding Status --- 
  sharding version: {
        "_id" : 1,
        "minCompatibleVersion" : 5,
        "currentVersion" : 6,
        "clusterId" : ObjectId("5bd8849513e9f7fb57277071")
  }
  shards:
        {  "_id" : "shard1",  "host" : "shard1/172.16.0.192:27018,172.16.0.193:27018,172.16.0.194:27018",  "state" : 1 }
        {  "_id" : "shard2",  "host" : "shard2/172.16.0.192:27019,172.16.0.193:27019,172.16.0.194:27019",  "state" : 1 }
        {  "_id" : "shard3",  "host" : "shard3/172.16.0.192:27020,172.16.0.193:27020,172.16.0.194:27020",  "state" : 1 }
  active mongoses:
        "4.0.3" : 3
  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 }
                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" : "testShard",  "primary" : "shard2",  "partitioned" : false,  "version" : {  "uuid" : UUID("842f5428-9e0a-49b4-9c18-ff1c95d1bfea"),  "lastMod" : 1 } }
        #数据库testShard目前不支持分片（"partitioned" :false），数据库文件存储在shard2片上（"primary" : "shard2"）

3、MongoDB分片是针对集合的，要想使集合支持分片，首先需要使其数据库支持分片，为数据库testShard激活分片

mongos> sh.enableSharding("testShard")
{
        "ok" : 1,
        "operationTime" : Timestamp(1540986138, 3),
        "$clusterTime" : {
                "clusterTime" : Timestamp(1540986138, 3),
                "signature" : {
                        "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
                        "keyId" : NumberLong(0)
                }
        }
}

4、为分片字段建立索引，同时为集合指定片键

mongos> db.users.ensureIndex({city:1})
{
        "raw" : {
                "shard3/172.16.0.192:27020,172.16.0.193:27020,172.16.0.194:27020" : {
                        "createdCollectionAutomatically" : false,
                        "numIndexesBefore" : 1,
                        "numIndexesAfter" : 2,
                        "ok" : 1
                }
        },
        "ok" : 1,
        "operationTime" : Timestamp(1540986455, 8),
        "$clusterTime" : {
                "clusterTime" : Timestamp(1540986455, 8),
                "signature" : {
                        "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
                        "keyId" : NumberLong(0)
                }
        }
}
mongos>  sh.shardCollection("testShard.users",{city:1})  
{
        "ok" : 0,
        "errmsg" : "Please create an index that starts with the proposed shard key before sharding the collection",
        "code" : 72,
        "codeName" : "InvalidOptions",
        "operationTime" : Timestamp(1540986499, 4),
        "$clusterTime" : {
                "clusterTime" : Timestamp(1540986499, 4),
                "signature" : {
                        "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
                        "keyId" : NumberLong(0)
                }
        }
}
mongos> 

5、再次查看分片集群状态

mongos> sh.status()
--- Sharding Status --- 
  sharding version: {
        "_id" : 1,
        "minCompatibleVersion" : 5,
        "currentVersion" : 6,
        "clusterId" : ObjectId("5bd8849513e9f7fb57277071")
  }
  shards:
        {  "_id" : "shard1",  "host" : "shard1/172.16.0.192:27018,172.16.0.193:27018,172.16.0.194:27018",  "state" : 1 }
        {  "_id" : "shard2",  "host" : "shard2/172.16.0.192:27019,172.16.0.193:27019,172.16.0.194:27019",  "state" : 1 }
        {  "_id" : "shard3",  "host" : "shard3/172.16.0.192:27020,172.16.0.193:27020,172.16.0.194:27020",  "state" : 1 }
  active mongoses:
        "4.0.3" : 3
  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 }
                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" : "test",  "primary" : "shard3",  "partitioned" : false,  "version" : {  "uuid" : UUID("fabfdcc3-0757-4042-be35-39efe9691f86"),  "lastMod" : 1 } }
        {  "_id" : "testShard",  "primary" : "shard2",  "partitioned" : true,  "version" : {  "uuid" : UUID("842f5428-9e0a-49b4-9c18-ff1c95d1bfea"),  "lastMod" : 1 } }
                testShard.users
                        shard key: { "city" : 1 }
                        unique: false
                        balancing: true
                        chunks:
                                shard2  1
                        { "city" : { "$minKey" : 1 } } -->> { "city" : { "$maxKey" : 1 } } on : shard2 Timestamp(1, 0) 
　　　　　　　　　#数据库testShard支持分片（"partitioned" :true），数据库文件存储在shard2片上

mongos> 

6、向集群插入测试数据

mongos> for(var i=1;i<1000000;i++) db.users.insert({userid:i,username:"chavin"+i,city:"beijing"})
mongos> for(var i=1;i<1000000;i++) db.users.insert({userid:i,username:"dbking"+i,city:"changsha"})

 7、再次查看分片集群状态

mongos> sh.status()
--- Sharding Status --- 
  sharding version: {
        "_id" : 1,
        "minCompatibleVersion" : 5,
        "currentVersion" : 6,
        "clusterId" : ObjectId("5bd8849513e9f7fb57277071")
  }
  shards:
        {  "_id" : "shard1",  "host" : "shard1/172.16.0.192:27018,172.16.0.193:27018,172.16.0.194:27018",  "state" : 1 }
        {  "_id" : "shard2",  "host" : "shard2/172.16.0.192:27019,172.16.0.193:27019,172.16.0.194:27019",  "state" : 1 }
        {  "_id" : "shard3",  "host" : "shard3/172.16.0.192:27020,172.16.0.193:27020,172.16.0.194:27020",  "state" : 1 }
  active mongoses:
        "4.0.3" : 3
  autosplit:
        Currently enabled: yes
  balancer:
        Currently enabled:  yes
        Currently running:  no
        Failed balancer rounds in last 5 attempts:  5
        Last reported error:  Could not find host matching read preference { mode: "primary" } for set shard2
        Time of Reported error:  Thu Nov 01 2018 18:22:23 GMT+0800 (CST)
        Migration Results for the last 24 hours: 
                2 : Success
  databases:
        {  "_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" : "test",  "primary" : "shard3",  "partitioned" : false,  "version" : {  "uuid" : UUID("fabfdcc3-0757-4042-be35-39efe9691f86"),  "lastMod" : 1 } }
        {  "_id" : "testShard",  "primary" : "shard2",  "partitioned" : true,  "version" : {  "uuid" : UUID("842f5428-9e0a-49b4-9c18-ff1c95d1bfea"),  "lastMod" : 1 } }
                testShard.users
                        shard key: { "city" : 1 }
                        unique: false
                        balancing: true
                        chunks:
                                shard1  1
                                shard2  1
                                shard3  1
                        { "city" : { "$minKey" : 1 } } -->> { "city" : "beijing" } on : shard3 Timestamp(3, 0) 
                        { "city" : "beijing" } -->> { "city" : "shanghai" } on : shard2 Timestamp(3, 1) 
                        { "city" : "shanghai" } -->> { "city" : { "$maxKey" : 1 } } on : shard1 Timestamp(2, 0) 
　　　　　　　　　　#数据库testShard支持分片（"partitioned" :true），数据库文件存储在shard1、shard2片、shard3上

测试完毕