Mongodb分片集群介绍
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，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。
服务器规划
下载 Mongodb
https://www.mongodb.com/download-center/community
wget -c https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-rhel70-4.0.8.tgz解压包 Mongodb 包
tar -zxvf mongodb-linux-x86_64-rhel70-4.0.7.tgz -C /usr/local/mongodb添加环境变量
export MONGO_HOME=/usr/local/mongodb
export PATH=$PATH:$MONGO_HOME/bin集群准备
新建 Mongodb 需要的目录
在192.168.2.177服务器上操作，以下配置操作均在192.168.2.177上进行
mkdir -p /wdata/mongodb/{data,logs,config,keys}
mkdir -p /wdata/mongodb/data/{mongosrv,shard1}将新建的目录发送到另外两台服务器
for i in 178 180; do scp -r /wdata/mongodb root@192.168.2.$i; done生成分片集群的key文件
openssl rand -base64 90 -out /wdata/mongodb/keys/keyfile修改key文件属性
chmod 600 /wdata/mongodb/keys/keyfile注意：此处必须修改，否则可能报错
编辑 mongos.conf 文件
systemLog:
destination: file
#日志存储位置
path: /wdata/mongodb/logs/mongos.log
logAppend: true
processManagement:
#fork and run in background
fork: true
pidFilePath: /wdata/mongodb/data/mongos.pid
#端口配置
net:
port: 30000
maxIncomingConnections: 500
unixDomainSocket:
enabled: true
#pathPrefix: /tmp
filePermissions: 0700
bindIp: 0.0.0.0
security:
keyFile: /wdata/mongodb/keys/keyfile
#将 confige server 添加到路由
sharding:
configDB: configs/192.168.2.177:21000,192.168.2.178:21000,192.168.2.180:21000编辑 mongosrv1.conf 文件
systemLog:
destination: file
logAppend: true
path: /wdata/mongodb/logs/mongosrv.log
storage:
dbPath: /wdata/mongodb/data/mongosrv
journal:
enabled: true
wiredTiger:
engineConfig:
directoryForIndexes: true
processManagement:
# fork and run in background
fork: true
# location of pidfile
pidFilePath: /wdata/mongodb/data/mongosrv/mongosrv.pid
net:
port: 21000
#bindIp: 0.0.0.0 # Enter 0.0.0.0,:: to bind to all IPv4 and IPv6 addresses or, alternatively, use the net.bindIpAll setting.
bindIpAll: true
maxIncomingConnections: 65535
unixDomainSocket:
enabled: true
filePermissions: 0700
security:
keyFile: /wdata/mongodb/keys/keyfile
authorization: enabled
replication:
replSetName: configs
sharding:
clusterRole: configsvr说明：该文件在此环境需要3个，分布在3台服务器，这里仅配置1个
编辑 shard1.conf 文件
systemLog:
destination: file
logAppend: true
path: /wdata/mongodb/logs/shard1.log
storage:
dbPath: /wdata/mongodb/data/shard1
journal:
enabled: true
wiredTiger:
engineConfig:
directoryForIndexes: true
processManagement:
# fork and run in background
fork: true
pidFilePath: /wdata/mongodb/data/mongosrv/mongosrv.pid # location of pidfile
# timeZoneInfo: /usr/share/zoneinfo
net:
port: 27001
# bindIp: 0.0.0.0 # Enter 0.0.0.0,:: to bind to all IPv4 and IPv6 addresses or, alternatively, use the net.bindIpAll setting.
bindIpAll: true
maxIncomingConnections: 65535
unixDomainSocket:
enabled: true
# pathPrefix: /tmp/mongod1
filePermissions: 0700
security:
keyFile: /wdata/mongodb/keys/keyfile
authorization: enabled
replication:
replSetName: shard1
sharding:
clusterRole: shardsvr说明：shard在一台服务器上也可以配置多个，建不同的目录充当分片服务器，看需求而定
将配置文件到其他两台服务器
for i in 178 180; do scp -r /wdata/mongodb/config root@192.168.2.$i:/wdata/mongodb/; done启动集群
在192.168.1.177上启动
mongod -f /wdata/mongodb/config/mongosrv1.conf
mongod -f /wdata/mongodb/config/shard1.conf
mongos -f /wdata/mongodb/config/mongos.conf
在192.168.1.178上启动
mongod -f /wdata/mongodb/config/mongosrv1.conf
mongod -f /wdata/mongodb/config/shard1.conf
mongos -f /wdata/mongodb/config/mongos.conf
在192.168.1.180上启动
mongod -f /wdata/mongodb/config/mongosrv1.conf
mongod -f /wdata/mongodb/config/shard1.conf
mongos -f /wdata/mongodb/config/mongos.conf分片集群创建副本集
在192.168.2.177上操作
[root@localhost mongodb]# mongo --port 27001
MongoDB shell version v4.0.7
connecting to: mongodb://127.0.0.1:27001/?gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("b56157d2-fbc7-4226-aeb4-4de0b79dfcda") }
MongoDB server version: 4.0.7
> use admin
switched to db admin
> config = {_id: 'shard1', members: [{_id: 0, host: '192.168.2.177:27001'},{_id: 1, host: '192.168.2.178:27001'},{_id: 2, host:'192.168.2.180:27001'}]}
{
"_id" : "shard1",
"members" : [
{
"_id" : 0,
"host" : "192.168.2.177:27001"
},
{
"_id" : 1,
"host" : "192.168.2.178:27001"
},
{
"_id" : 2,
"host" : "192.168.2.180:27001"
}
]
}
> rs.initiate(config)
{ "ok" : 1 }
shard1:PRIMARY> rs.status()
{
"set" : "shard1",
"date" : ISODate("2019-04-03T10:08:16.477Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1554286090, 1),
"t" : NumberLong(1)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1554286090, 1),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1554286090, 1),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1554286090, 1),
"t" : NumberLong(1)
}
},
"lastStableCheckpointTimestamp" : Timestamp(1554286040, 2),
"members" : [
{
"_id" : 0,
"name" : "192.168.2.177:27001",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 2657,
"optime" : {
"ts" : Timestamp(1554286090, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-04-03T10:08:10Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1554286040, 1),
"electionDate" : ISODate("2019-04-03T10:07:20Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 1,
"name" : "192.168.2.178:27001",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 67,
"optime" : {
"ts" : Timestamp(1554286090, 1),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1554286090, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-04-03T10:08:10Z"),
"optimeDurableDate" : ISODate("2019-04-03T10:08:10Z"),
"lastHeartbeat" : ISODate("2019-04-03T10:08:16.259Z"),
"lastHeartbeatRecv" : ISODate("2019-04-03T10:08:15.440Z"),
"pingMs" : NumberLong(6),
"lastHeartbeatMessage" : "",
"syncingTo" : "192.168.2.177:27001",
"syncSourceHost" : "192.168.2.177:27001",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 1
},
{
"_id" : 2,
"name" : "192.168.2.180:27001",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 67,
"optime" : {
"ts" : Timestamp(1554286090, 1),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1554286090, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-04-03T10:08:10Z"),
"optimeDurableDate" : ISODate("2019-04-03T10:08:10Z"),
"lastHeartbeat" : ISODate("2019-04-03T10:08:16.219Z"),
"lastHeartbeatRecv" : ISODate("2019-04-03T10:08:15.440Z"),
"pingMs" : NumberLong(4),
"lastHeartbeatMessage" : "",
"syncingTo" : "192.168.2.177:27001",
"syncSourceHost" : "192.168.2.177:27001",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 1
}
],
"ok" : 1
}
shard1:PRIMARY> exit
bye创建分片集群数据库和用户
[root@localhost mongodb]# mongo --port 27001
MongoDB shell version v4.0.7
connecting to: mongodb://127.0.0.1:27001/?gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("a4c12af4-85e2-49e3-9a02-dd481307bcda") }
MongoDB server version: 4.0.7
shard1:PRIMARY> use admin
switched to db admin
shard1:PRIMARY> db.createUser({user:"admin",pwd:"123456",roles:[{role:"userAdminAnyDatabase",db:"admin"}]})
Successfully added user: {
"user" : "admin",
"roles" : [
{
"role" : "userAdminAnyDatabase",
"db" : "admin"
}
]
}
shard1:PRIMARY> db.auth("admin","123456")
1
shard1:PRIMARY> use test
switched to db test
shard1:PRIMARY> db.createUser({user:"root",pwd:"123456",roles:[{role:"dbOwner",db:"test"}]})
Successfully added user: {
"user" : "root",
"roles" : [
{
"role" : "dbOwner",
"db" : "test"
}
]
}
shard1:PRIMARY> exit
bye配置 mongosrv 副本集
[root@localhost config]# mongo --port 21000
MongoDB shell version v4.0.7
connecting to: mongodb://127.0.0.1:21000/?gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("f9896034-d90f-4d52-bc55-51c3dc85aae9") }
MongoDB server version: 4.0.7
> config = {_id: 'configs', members: [{_id: 0, host: '192.168.2.177:21000'},{_id: 1, host: '192.168.2.178:21000'},{_id: 2, host: '192.168.2.180:21000'}]}
{
"_id" : "configs",
"members" : [
{
"_id" : 0,
"host" : "192.168.2.177:21000"
},
{
"_id" : 1,
"host" : "192.168.2.178:21000"
},
{
"_id" : 2,
"host" : "192.168.2.180:21000"
}
]
}
> rs.initiate(config)
{
"ok" : 1,
"$gleStats" : {
"lastOpTime" : Timestamp(1554288851, 1),
"electionId" : ObjectId("000000000000000000000000")
},
"lastCommittedOpTime" : Timestamp(0, 0)
}
configs:SECONDARY> rs.status(config)
{
"set" : "configs",
"date" : ISODate("2019-04-03T10:54:43.283Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"configsvr" : true,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1554288879, 4),
"t" : NumberLong(1)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1554288879, 4),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1554288879, 4),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1554288879, 4),
"t" : NumberLong(1)
}
},
"lastStableCheckpointTimestamp" : Timestamp(1554288864, 1),
"members" : [
{
"_id" : 0,
"name" : "192.168.2.177:21000",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 5454,
"optime" : {
"ts" : Timestamp(1554288879, 4),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-04-03T10:54:39Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1554288863, 1),
"electionDate" : ISODate("2019-04-03T10:54:23Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 1,
"name" : "192.168.2.178:21000",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 31,
"optime" : {
"ts" : Timestamp(1554288879, 4),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1554288879, 4),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-04-03T10:54:39Z"),
"optimeDurableDate" : ISODate("2019-04-03T10:54:39Z"),
"lastHeartbeat" : ISODate("2019-04-03T10:54:41.362Z"),
"lastHeartbeatRecv" : ISODate("2019-04-03T10:54:41.906Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "192.168.2.177:21000",
"syncSourceHost" : "192.168.2.177:21000",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 1
},
{
"_id" : 2,
"name" : "192.168.2.180:21000",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 31,
"optime" : {
"ts" : Timestamp(1554288879, 4),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1554288879, 4),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-04-03T10:54:39Z"),
"optimeDurableDate" : ISODate("2019-04-03T10:54:39Z"),
"lastHeartbeat" : ISODate("2019-04-03T10:54:41.362Z"),
"lastHeartbeatRecv" : ISODate("2019-04-03T10:54:41.597Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "192.168.2.177:21000",
"syncSourceHost" : "192.168.2.177:21000",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 1
}
],
"ok" : 1,
"operationTime" : Timestamp(1554288879, 4),
"$gleStats" : {
"lastOpTime" : Timestamp(1554288851, 1),
"electionId" : ObjectId("7fffffff0000000000000001")
},
"lastCommittedOpTime" : Timestamp(1554288879, 4),
"$clusterTime" : {
"clusterTime" : Timestamp(1554288879, 4),
"signature" : {
"hash" : BinData(0,"VVM2Bsa9KiZy8Sew9Oa8CsbDBPU="),
"keyId" : NumberLong("6675619852301893642")
}
}
}
configs:PRIMARY>到此mongodb分片集群部署完成后，后面附上 Mongodb 常见操作指令
show dbs #查看所有数据库
db #查看当前所在的数据库
sh.status() #查看集群的信息
sh.enableSharding("dba") #对数据库启用分片
db.help() #查看帮助
db.account.stats() #查看数据集合的分布情况
db.createUser() #新建用户
use databasename #进入或者新建数据库
db.shutdownServer() #关闭数据库
db.dropDatabase() #删除数据库（必须先切换到该数据库）
