配置MongoDB复制集以及如何管理？

前言

• 基于之前的环境操作，可以看我之前的博客
  链接: https://blog.csdn.net/m0_47219942/article/details/108552702.

实操过程

配置复制集

• 修改配置文件

vim /etc/mongod.conf 
replication:			#去掉
        replSetName: kgcrs	定义复制集的名称

• 配置多个复制集，并重新开启服务

[root@localhost school]# mongod -f /etc/mongod.conf --shutdown  '关闭单个实例'
killing process with pid: 12630
[root@localhost school]# mongod -f /etc/mongod.conf  '开启单个实例服务'
about to fork child process, waiting until server is ready for connections.
forked process: 68928
child process started successfully, parent exiting

[root@localhost school]# vim /etc/mongod2.conf
replication:
    replSetName: kgcrs 
[root@localhost school]# mongod -f /etc/mongod2.conf --shutdown
[root@localhost school]# mongod -f /etc/mongod2.conf

• 修改复制集的主从

[root@localhost school]# mongo
> db.stats()
> cfg={
     "_id":"kgcrs","members":[{
     "_id":0,"host":"20.0.0.51:27017"},{
     "_id":1,"host":"20.0.0.51:27018"}]}
{
     
	"_id" : "kgcrs",
	"members" : [
		{
     
			"_id" : 0,
			"host" : "20.0.0.51:27017"
		},
		{
     
			"_id" : 1,
			"host" : "20.0.0.51:27018"
		}
	]
}
> db.stats()    '查看复制集'
> rs.initiate(cfg)   '启动复制集'
kgcrs:PRIMARY>        '变为主'
[root@localhost logs]# mongo --port 27018    '切换为18'
kgcrs:SECONDARY>        '18变为从'
[root@localhost logs]# mongo --port 27017    '切换为17'
kgcrs:SECONDARY>      '17变为从'
kgcrs:PRIMARY> rs.status()     '查看复制级状态 ''

• 添加复制集节点

kgcrs:PRIMARY> rs.add("20.0.0.51:27020")    '添加27020的节点'
kgcrs:PRIMARY> rs.status()    '查看节点是否添加'

• 删除复制集节点

kgcrs:PRIMARY> rs.remove("20.0.0.51:27020")

故障转移切换

• 查看进程

[root@localhost school]# ps aux |grep mongod
root      68928  0.6  2.6 1510380 100764 ?      Sl   10:53   0:20 mongod -f /etc/mongod.conf
root      69124  0.6  2.5 1473404 98512 ?       Sl   11:06   0:17 mongod -f /etc/mongod2.conf
root      69661  0.0  0.0 112724   988 pts/2    S+   11:48   0:00 grep --color=auto mongod

• 模拟故障，复制集完成自动切换，将主数据库的进程删除，查看选举情况，哪台变为主键

[root@localhost logs]# kill -9 68928    ##将主键的PID号删除
[root@localhost logs]# mongo --port 27018    ##登录到27018的数据库
发现27018变为主键
手动切换
kgcrs:PRIMARY> rs.freeze(30)    ##暂停30s不参与选举
kgcrs:PRIMARY> rs.stepDown(60,30)  ##交出主节点位置，维持从节点状态不少于60s,等待30s使主节点和从节点日志同步（交换主从）

复制集管理

'选举复制'
1.标准节点 2.仲裁节点 3.被动节点
'通过优先级设点，优先级高的是标准节点，低的是被动节点；最后是仲裁节点'
[root@localhost logs]# mongo    '在实例1中设置优先级'
> cfg={
     "_id":"kgcrs","members":[{
     "_id":0,"host":"20.0.0.51:27017","priority":100},{
     "_id":1,"host":"20.0.0.51:27018","priority":100},{
     "_id":2,"host":"20.0.0.51:27019","priority":0},{
     "_id":3,"host":"20.0.0.51:27020","arbiterOnly":true}]}
> rs.initiate(cfg)     '将（cfg）进行初始化，会发现27017变为主键'
kgcrs:PRIMARY> rs.isMaster()     '查看各节点之间的身份'

'添加数据'
kgcrs:PRIMARY> use test      '使用test库'
switched to db test
kgcrs:PRIMARY> db.t1.insert({
     "id":1,"name":"jack"})    #创建id为1的“jack”用户
WriteResult({
      "nInserted" : 1 })
kgcrs:PRIMARY> db.t1.insert({
     "id":2,"name":"tom"})    #创建id为2的“tom”用户
WriteResult({
      "nInserted" : 1 })
kgcrs:PRIMARY> db.t1.find()
{
      "_id" : ObjectId("5f5c2ac07a3ce48c6ccb1dd4"), "id" : 1, "name" : "jack" }
{
      "_id" : ObjectId("5f5c2ac97a3ce48c6ccb1dd5"), "id" : 2, "name" : "tom" }

'修改数据'
kgcrs:PRIMARY> db.t1.update({
     "id":1},{
     $set:{
     "name":"jerrt"}})
WriteResult({
      "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
kgcrs:PRIMARY> db.t1.find()
{
      "_id" : ObjectId("5f5c2ac07a3ce48c6ccb1dd4"), "id" : 1, "name" : "jerrt" }
{
      "_id" : ObjectId("5f5c2ac97a3ce48c6ccb1dd5"), "id" : 2, "name" : "tom" }
kgcrs:PRIMARY> 

'删除数据'
kgcrs:PRIMARY> db.t1.remove({
     "id":2})
WriteResult({
      "nRemoved" : 1 })
kgcrs:PRIMARY> db.t1.find()
{
      "_id" : ObjectId("5f5c2ac07a3ce48c6ccb1dd4"), "id" : 1, "name" : "jerrt" }

'查看日志信息'
kgcrs:PRIMARY> show dbs
local   0.000GB     'local库存放了日志'
kgcrs:PRIMARY> show collections     '查看集合'
oplog.rs       ##存放了日志信息
kgcrs:PRIMARY> db.oplog.rs.find()     '查看日志记录'


——————模拟节点故障查看选举情况
[root@localhost logs]# mongod -f /etc/mongod.conf --shutdown    '将主节点宕机'
[root@localhost logs]# mongo --port 27018     '用主键中的27018去登录'
kgcrs:PRIMARY>     '发现27018变为主键'
'这时将27018也宕机，查看27019会不会参与选举'
[root@localhost logs]# mongod -f /etc/mongod2.conf --shutdown     ##将27018宕机
[root@localhost logs]# mongo --port 27019
kgcrs:SECONDARY>     '发现27019不参与选举'
再次将27017恢复，发现主节点依然是他
[root@localhost logs]# mongod -f /etc/mongod.conf      '恢复端口27017'
kgcrs:PRIMARY>      '发现其还是变为主节点'

允许从节点从主节点去读取信息
[root@localhost logs]# mongo --port 27018     '登录到27018节点上'
kgcrs:SECONDARY> show dbs      '发现查看不到数据库信息'
kgcrs:SECONDARY> rs.slaveOk()     '允许从节点去读取信息'
kgcrs:SECONDARY> show dbs
admin   0.000GB
config  0.000GB
local   0.000GB
test    0.000GB     '数据库信息就存在了'

'查看复制状态信息'
kgcrs:SECONDARY> rs.printReplicationInfo()     '查看日志文件大小'
configured oplog size:   1830.852294921875MB        '日志文件大小为1830MB'
kgcrs:SECONDARY> rs.printSlaveReplicationInfo()   '查看哪些节点可以找主节点同步'
source: 20.0.0.51:27018     '27018'
	syncedTo: Sat Sep 12 2020 10:30:58 GMT+0800 (CST)
	0 secs (0 hrs) behind the primary 
source: 20.0.0.51:27019    '27019'
	syncedTo: Sat Sep 12 2020 10:30:58 GMT+0800 (CST)
	0 secs (0 hrs) behind the primary 
'仲裁节点不会去找主节点同步信息'
'更改日志文件大小'
'将27018的服务关闭'
kgcrs:SECONDARY> use admin
switched to db admin
kgcrs:SECONDARY> db.shutdownServer()
'将配置文件信息注释'
[root@localhost logs]# vim /etc/mongod2.conf 
net:
  port: 27028    '将端口号改为27028'
  bindIp: 0.0.0.0  # Listen to local interface only, comment to listen on all interfaces.
#replication:                     '将参数注销'
#     replSetName: kgcrs
[root@localhost logs]# mongod -f /etc/mongod2.conf    '重新启动27018端口的实例，这时它就变成一个单实例'
[root@localhost logs]# mongodump --port 27028 --db local --collection 'oplog.rs'   '备份日志信息'
[root@localhost logs]# mongo --port 27028
> use local     '使用local库'
switched to db local
> show tables     
me
oplog.rs  
replset.election
replset.minvalid
replset.oplogTruncateAfterPoint
startup_log
system.replset
system.rollback.id
> db.oplog.rs.drop()     '将日志库删除'
true
> db.run
db.runCommand(              db.runReadCommand(
db.runCommandWithMetadata(
> db.runCommand( {
      create: "oplog.rs", capped: true, size: (2 * 1024 * 1024) } )    '重建日志信息库'
{
      "ok" : 1 }
> use admin     '改完之后将服务停止'
switched to db admin
> db.shutdownServer()
3.修改配置文件，将注释取消，修改端口号

net:
  port: 27018    '端口号改为27018'
......
replication:    
     replSetName: kgcrs
     oplogSizeMB: 2048     '添加日志库大小为2048M'      
[root@localhost logs]# mongod -f /etc/mongod2.conf 
[root@localhost logs]# mongo --port 27018
kgcrs:SECONDARY> rs.printReplicationInfo()    '查看文件大小'
configured oplog size:   2MB
log length start to end: 240secs (0.07hrs)
oplog first event time:  Sat Sep 12 2020 11:02:59 GMT+0800 (CST)
oplog last event time:   Sat Sep 12 2020 11:06:59 GMT+0800 (CST)
now:                     Sat Sep 12 2020 11:07:04 GMT+0800 (CST)

[root@localhost logs]# mongo    '登录到主节点上'
kgcrs:PRIMARY> rs.stepDown()    '将主位让出'
[root@localhost logs]# mongo --port 27018    '再次登陆的27018节点上'
kgcrs:PRIMARY>    '27018变为主节点'


'部署认证复制'
kgcrs:PRIMARY> use admin
switched to db admin
kgcrs:PRIMARY> db.createUser({
     "user":"root","pwd":"123","roles":["root"]})    '创建用户'
Successfully added user: {
      "user" : "root", "roles" : [ "root" ] }
[root@localhost logs]# vim /etc/mongod.conf
security:
   keyFile: /usr/bin/kgcrskey1    '验证路径'
   clusterAuthMode: keyFile    '密钥文件验证'
[root@localhost logs]# vim /etc/mongod2.conf
security:
   keyFile: /usr/bin/kgcrskey2    
   clusterAuthMode: keyFile    
[root@localhost logs]# vim /etc/mongod3.conf
security:
   keyFile: /usr/bin/kgcrskey    
   clusterAuthMode: keyFile   
[root@localhost logs]# vim /etc/mongod4.conf
security:
   keyFile: /usr/bin/kgcrskey4   
   clusterAuthMode: keyFile  
'写入4个密钥文件'
[root@localhost logs]# cd /usr/bin/
[root@localhost bin]# echo "kgcrs key" > kgcrskey1
[root@localhost bin]# echo "kgcrs key" > kgcrskey2
[root@localhost bin]# echo "kgcrs key" > kgcrskey3
[root@localhost bin]# echo "kgcrs key" > kgcrskey4
[root@localhost bin]# chmod 600 kgc*    '将文件权限改为600'

'将文件全部生效；这边就距离27017节点的例子'
[root@localhost bin]# mongod -f /etc/mongod.conf --shutdown   
killing process with pid: 11907
[root@localhost bin]# mongod -f /etc/mongod.conf 

'登录到主位节点，验证认证测试'
[root@localhost bin]# mongo --port 27018  
kgcrs:PRIMARY> show dbs
    "errmsg" : "there are no users authenticated",'会显示需要验证，看不到信息'
kgcrs:PRIMARY> use admin
switched to db admin
kgcrs:PRIMARY> db.auth("root","123")   '用root身份去登录'
1
kgcrs:PRIMARY> show dbs   '可以查看数据库信息了'
admin   0.000GB
config  0.000GB
local   0.000GB
test    0.000GB
kgcrs:PRIMARY> 
'从位的节点都需要登录root用户才可以查看数据库信息'