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在上一篇文章中，我们基本了解了分片的概念，本文将着手实践，进行分片集群的搭建
首先我们再来了解一下分片集群的架构，分片集群由三部分构成：
（一）主机信息
（二）配置服务器副本集搭建
配置服务器三个实例的基础规划如下：
member0 192.168.10.80:27017
member1 192.168.10.80:27018
member2 192.168.10.80:27019
其参数规划如下：
接下来，我们一步一步搭建config server的副本集。
STEP1：解压mongodb安装包到/mongo目录
[root@mongosserver mongo]# pwd /mongo [root@mongosserver mongo]# ls bin LICENSE-Community.txt MPL-2 README THIRD-PARTY-NOTICES THIRD-PARTY-NOTICES.gotools
STEP2：根据上面参数规划，创建数据存放相关路径
# 创建文件路径 mkdir -p /replset/repset1/data mkdir -p /replset/repset1/log mkdir -p /replset/repset2/data mkdir -p /replset/repset2/log mkdir -p /replset/repset3/data mkdir -p /replset/repset3/log [root@mongosserver repset1]# tree /replset/ /replset/ ├── repset1 │ ├── data │ ├── log │ └── mongodb.conf ├── repset2 │ ├── data │ └── log └── repset3 ├── data └── log
STEP3：为3个实例创建参数文件
实例1的参数文件 /replset/repset1/mongodb.conf ：
systemLog: destination: file logAppend: true path: /replset/repset1/log/mongodb.log storage: dbPath: /replset/repset1/data journal: enabled: true processManagement: fork: true # fork and run in background pidFilePath: /replset/repset1/mongod.pid # location of pidfile timeZoneInfo: /usr/share/zoneinfo # network interfaces net: port: 27017 bindIp: 0.0.0.0 # shard sharding: clusterRole: configsvr # repliuca set replication: replSetName: conf
实例2的参数文件 /replset/repset2/mongodb.conf ：
systemLog: destination: file logAppend: true path: /replset/repset2/log/mongodb.log storage: dbPath: /replset/repset2/data journal: enabled: true processManagement: fork: true # fork and run in background pidFilePath: /replset/repset2/mongod.pid # location of pidfile timeZoneInfo: /usr/share/zoneinfo # network interfaces net: port: 27018 bindIp: 0.0.0.0 # shard sharding: clusterRole: configsvr # repliuca set replication: replSetName: conf
实例3的参数文件 /replset/repset3/mongodb.conf ：
systemLog: destination: file logAppend: true path: /replset/repset3/log/mongodb.log storage: dbPath: /replset/repset3/data journal: enabled: true processManagement: fork: true # fork and run in background pidFilePath: /replset/repset3/mongod.pid # location of pidfile timeZoneInfo: /usr/share/zoneinfo # network interfaces net: port: 27019 bindIp: 0.0.0.0 # shard sharding: clusterRole: configsvr # repliuca set replication: replSetName: conf
STEP4：启动三个mongod实例
mongod -f /replset/repset1/mongodb.conf mongod -f /replset/repset2/mongodb.conf mongod -f /replset/repset3/mongodb.conf # 查看是成功否启动 [root@mongosserver mongo]# netstat -nltp |grep mongod tcp 0 0 0.0.0.0:27019 0.0.0.0:* LISTEN 28009/mongod tcp 0 0 0.0.0.0:27017 0.0.0.0:* LISTEN 27928/mongod tcp 0 0 0.0.0.0:27018 0.0.0.0:* LISTEN 27970/mongod
STEP5：进入任意一个实例，初始化配置服务器的副本集
rs.initiate( { _id: "conf", configsvr: true, members: [ { _id : 0, host : "192.168.10.80:27017" }, { _id : 1, host : "192.168.10.80:27018" }, { _id : 2, host : "192.168.10.80:27019" } ] } )
STEP6：[可选] 调整节点优先级，以便于确定主节点
cfg = rs.conf() cfg.members[0].priority = 3 cfg.members[1].priority = 2 cfg.members[2].priority = 1 rs.reconfig(cfg)
对于members[n]的定义：n是members数组中的数组位置，数组以0开始，千万不能将其理解为“members[n]._id”的_id值。
查看节点优先级：
conf:PRIMARY> rs.config()
（三）分片副本集搭建
分片1副本集成员：
member0 192.168.10.81:27017
member1 192.168.10.81:27018
member2 192.168.10.81:27019
分片2副本集成员：
member0 192.168.10.82:27017
member1 192.168.10.82:27018
member2 192.168.10.82:27019
分片3副本集成员：
member0 192.168.10.83:27017
member1 192.168.10.83:27018
member2 192.168.10.83:27019
其参数规划如下：
这里一共有3个分片，每个分片都是3个节点的副本集，副本集的搭建过程与上面config server副本集搭建过程相似，这里不再重复赘述，唯一不同的是副本集的初始化。shard副本集的初始化与配置副本集初始化过程相比，少了 configsvr: true 的参数配置。
三个shard副本集的初始化：
# shard001
rs.initiate( { _id: "shard001", members: [ { _id : 0, host : "192.168.10.81:27017" }, { _id : 1, host : "192.168.10.81:27018" }, { _id : 2, host : "192.168.10.81:27019" } ] } )
# shard002
rs.initiate( { _id: "shard002", members: [ { _id : 0, host : "192.168.10.82:27017" }, { _id : 1, host : "192.168.10.82:27018" }, { _id : 2, host : "192.168.10.82:27019" } ] } ) # shard003 rs.initiate( { _id: "shard003", members: [ { _id : 0, host : "192.168.10.83:27017" }, { _id : 1, host : "192.168.10.83:27018" }, { _id : 2, host : "192.168.10.83:27019" } ] } )
（四）配置并启动mongos
本次试验在192.168.10.100服务器上启动2个mongos进程，分别使用端口27000和28000。
STEP1：配置mongos实例的参数
端口27000参数配置，特别注意，需要先创建涉及到的路径：
systemLog: destination: file logAppend: true path: /mongo/log/mongos-27000.log processManagement: fork: true # fork and run in background pidFilePath: /mongo/mongod-27000.pid # location of pidfile timeZoneInfo: /usr/share/zoneinfo # network interfaces net: port: 27000 bindIp: 0.0.0.0 sharding: configDB: conf/192.168.10.80:27017,192.168.10.80:27018,192.168.10.80:27019
端口28000参数配置，特别注意，需要先创建涉及到的路径：
systemLog: destination: file logAppend: true path: /mongo/log/mongos-28000.log processManagement: fork: true # fork and run in background pidFilePath: /mongo/mongod-28000.pid # location of pidfile timeZoneInfo: /usr/share/zoneinfo # network interfaces net: port: 28000 bindIp: 0.0.0.0 sharding: configDB: conf/192.168.10.80:27017,192.168.10.80:27018,192.168.10.80:27019
STEP2：启动mongos实例
# 启动mongos实例 [root@mongosserver mongo]# mongos -f /mongo/mongos-27000.conf [root@mongosserver mongo]# mongos -f /mongo/mongos-28000.conf # 查看实例信息 [root@mongosserver mongo]# netstat -nltp|grep mongos tcp 0 0 0.0.0.0:27000 0.0.0.0:* LISTEN 2209/mongos tcp 0 0 0.0.0.0:28000 0.0.0.0:* LISTEN 2241/mongos
（五）添加分片到集群配置服务器
STEP1：使用mongo连接到mongos
mongo --host 192.168.10.100 --port 27000 # 或者 mongo --host 192.168.10.100 --port 28000
STEP2：添加分片到集群
sh.addShard( "shard001/192.168.10.81:27017,192.168.10.81:27018,192.168.10.81:27019") sh.addShard( "shard002/192.168.10.82:27017,192.168.10.82:27018,192.168.10.82:27019") sh.addShard( "shard003/192.168.10.83:27017,192.168.10.83:27018,192.168.10.83:27019")
STEP3：查看分片信息
mongos> sh.status() --- Sharding Status --- sharding version: { "_id" : 1, "minCompatibleVersion" : 5, "currentVersion" : 6, "clusterId" : ObjectId("5ffc0709b040c53d59c15c66") } shards: { "_id" : "shard001", "host" : "shard001/192.168.10.81:27017,192.168.10.81:27018,192.168.10.81:27019", "state" : 1 } { "_id" : "shard002", "host" : "shard002/192.168.10.82:27017,192.168.10.82:27018,192.168.10.82:27019", "state" : 1 } { "_id" : "shard003", "host" : "shard003/192.168.10.83:27017,192.168.10.83:27018,192.168.10.83:27019", "state" : 1 } active mongoses: "4.2.10" : 2 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 } mongos>
（六）启用分片
（6.1）对数据库启用分片
分片是以集合为单位进行的，在对一个集合进行分片之前，需要先对其数据库启用分片，对数据库启用分片并不会重新分发数据，只是说明该数据库上的集合可以进行分片操作。
sh.enableSharding("lijiamandb");
（6.2）对集合启用分片
如果集合已经存在数据，必须手动创建在分片键上创建索引，然后再对集合进行分片，如果集合为空，MongoDB会在分片的时候自动在分片键上创建索引。
mongodb提供了2种策略来对集合进行分片：
sh.shardCollection("<database>.<collection>",{shard key field : "hashed"})
sh.shardCollection("<database>.<collection>",{<shard key field>:1,...} )
例子:对集合user进行hash分片
// 连接到mongos，进入lijiamandb数据库，对新集合users插入10万条数据 use lijiamandb for (i=1;i<100000;i++){ db.user.insert({ "id" : i, "name" : "name"+i, "age" : Math.floor(Math.random()*120), "created" : new Date() }); } // 使用mongostat可以看到，所有数据都写入到了主节点(shard2)，每个数据库的主节点可能不同，可以使用sh.status()查看。 [root@mongosserver ~]# mongostat --port 27000 5 --discover host insert query update delete getmore command dirty used flushes mapped vsize res faults qrw arw net_in net_out conn set repl time localhost:27000 352 *0 *0 *0 0 704|0 0 0B 356M 32.0M 0 0|0 0|0 224k 140k 10 RTR Jan 15 10:52:32.046 host insert query update delete getmore command dirty used flushes mapped vsize res faults qrw arw net_in net_out conn set repl time 192.168.10.81:27017 *0 *0 *0 *0 0 2|0 0.3% 0.8% 0 1.90G 133M n/a 0|0 1|0 417b 9.67k 23 shard001 SEC Jan 15 10:52:32.061 192.168.10.81:27018 *0 *0 *0 *0 0 3|0 0.3% 0.8% 1 1.93G 132M n/a 0|0 1|0 1.39k 11.0k 28 shard001 PRI Jan 15 10:52:32.067 192.168.10.81:27019 *0 *0 *0 *0 0 2|0 0.3% 0.8% 0 1.95G 148M n/a 0|0 1|0 942b 10.2k 26 shard001 SEC Jan 15 10:52:32.070 192.168.10.82:27017 352 *0 *0 *0 407 1192|0 2.5% 11.7% 1 1.99G 180M n/a 0|0 1|0 1.52m 1.15m 29 shard002 PRI Jan 15 10:52:32.075 192.168.10.82:27018 *352 *0 *0 *0 409 441|0 4.5% 8.9% 0 1.96G 163M n/a 0|0 1|0 566k 650k 25 shard002 SEC Jan 15 10:52:32.085 192.168.10.82:27019 *352 *0 *0 *0 0 2|0 4.4% 9.7% 0 1.92G 168M n/a 0|0 1|0 406b 9.51k 24 shard002 SEC Jan 15 10:52:32.093 192.168.10.83:27017 *0 *0 *0 *0 0 1|0 0.2% 0.6% 1 1.89G 130M n/a 0|0 1|0 342b 9.17k 22 shard003 SEC Jan 15 10:52:32.099 192.168.10.83:27018 *0 *0 *0 *0 0 2|0 0.2% 0.6% 0 1.95G 139M n/a 0|0 1|0 877b 9.92k 28 shard003 PRI Jan 15 10:52:32.107 192.168.10.83:27019 *0 *0 *0 *0 0 1|0 0.2% 0.6% 0 1.90G 133M n/a 0|0 1|0 342b 9.17k 21 shard003 SEC Jan 15 10:52:32.113 localhost:27000 365 *0 *0 *0 0 731|0 0 0B 356M 32.0M 0 0|0 0|0 233k 145k 10 RTR Jan 15 10:52:37.047 // 使用分片键id创建hash分片，因为id上没有hash索引，会报错 sh.shardCollection("lijiamandb.user",{"id":"hashed"}) /* 1 */ { "ok" : 0.0, "errmsg" : "Please create an index that starts with the proposed shard key before sharding the collection", "code" : 72, "codeName" : "InvalidOptions", "operationTime" : Timestamp(1610679762, 4), "$clusterTime" : { "clusterTime" : Timestamp(1610679762, 4), "signature" : { "hash" : { "$binary" : "AAAAAAAAAAAAAAAAAAAAAAAAAAA=", "$type" : "00" }, "keyId" : NumberLong(0) } } } // 需要手动创建hash索引 db.user.ensureIndex() // 查看索引 /* 1 */ [ { "v" : 2, "key" : { "_id" : 1 }, "name" : "_id_", "ns" : "lijiamandb.user" }, { "v" : 2, "key" : { "id" : "hashed" }, "name" : "id_hashed", "ns" : "lijiamandb.user" } ] # 最后再重新分片即可 sh.shardCollection("lijiamandb".user,{"id":"hashed"})
到这里，我们分片集群环境已经搭建完成，接下来我们将会学习分片键的选择机制。
【完】
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相关文档合集： 1. MongoDB Sharding(一) -- 分片的概念 |
