mongodb 4.0副本集搭建

近期有同学问mongodb副本集难不难部署，我的回答是不难，很快，几分钟搞定，比mysql MHA简单的不止一点半点。那么到底如何部署呢？请看下文。

1. 准备工作

1.1 下载软件

选择版本并下载mongodb的软件，注意操作系统版本等。本次我选用的是percona分支的mongodb 4.2.8版本搭建，操作系统为centos6

cd /usr/local/

wget

https://www.percona.com/downloads/percona-server-mongodb-LATEST/percona-server-mongodb-4.2.8-8/binary/tarball/percona-server-mongodb-4.2.8-8-centos6-x86_64.tar.gz

tar -zxvf percona-server-mongodb-4.2.8-8-centos6-x86_64.tar.gz

ln -s percona-server-mongodb-4.2.8-8 mongodb

1.2 规划各节点角色

各节点角色如下

IP　port　role

192.168.128.20827017PRIMARY

192.168.128.20927017SECONDARY

192.168.128.20928017ARBITER

2 部署

2.1 创建各节点相关目录

[root@m1 ~]#mkdir-p /data/mongodb/27017/{data,logs,tmp,etc,keyfile}

[root@m1 ~]# cd /data/mongodb/27017/[root@m1 27017]# ll

总用量 20drwxr-xr-x2root root40968月716:59 data

drwxr-xr-x2root root40968月716:59 etc

drwxr-xr-x2root root40968月716:59 keyfile

drwxr-xr-x2root root40968月716:59 logs

drwxr-xr-x2root root40968月716:59tmp

2.2 配置文件

创建配置文件，并添加对应的配置信息，注意仲裁节点的端口

[root@m127017]# cd /data/mongodb/27017/etc/[root@m1 etc]# vim mongod.conf

添加如下内容

storage:

dbPath: /data/mongodb/27017/data

journal:

enabled: truesystemLog:

destination: file logAppend: true path: /data/mongodb/27017/logs/mongod.log

processManagement:

fork: true pidFilePath: /data/mongodb/27017/tmp/mongod.pid

net:

port: 27017 bindIp: 0.0.0.0

replication:

replSetName: "test1" # 副本集名称

2.3 启动各节点

以其中一个节点为例，其他节点修改对应配置文件即可

[root@m1 local]# /usr/local/mongodb/bin/mongod -f /data/mongodb/27017/etc/mongod.conf

about to fork child process, waiting untilserver is readyfor connections.

forked process: 30019child process started successfully, parent exiting

2.4 初始化副本集

初始化副本集，指定各节点id及角色，注意副本集的名称和配置文件里一致。

在任意节点执行如下语句

> use admin

switched to db admin> rs.initiate( {

... _id: "test1",

... members: [

... { _id: 0, host:"192.168.128.208:27017" },

... { _id: 1, host:"192.168.128.209:27017" },

... { _id: 2, host:"192.168.128.209:28017",arbiterOnly:true }

... ] })

{

"ok":1,

"$clusterTime" : {

"clusterTime": Timestamp(1596792682,1),

"signature" : {

"hash": BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),

"keyId": NumberLong(0)

}

"operationTime": Timestamp(1596792682,1)

}

完成后可以查看各集群状态,如下，可见当前192.168.128.208:27017 为PRIMARY节点

test1:PRIMARY> rs.status()

{

"set":"test1",

"date": ISODate("2020-08-07T11:09:24.454Z"),

"myState":1,

"term": NumberLong(1),

"syncingTo":"",

"syncSourceHost":"",

"syncSourceId": -1,

"heartbeatIntervalMillis": NumberLong(2000),

"majorityVoteCount":2,

"writeMajorityCount":2,

"optimes" : {

"lastCommittedOpTime" : {

"ts": Timestamp(1596798563,1),

"t": NumberLong(1)

"lastCommittedWallTime": ISODate("2020-08-07T11:09:23.663Z"),

"readConcernMajorityOpTime" : {

"ts": Timestamp(1596798563,1),

"t": NumberLong(1)

"readConcernMajorityWallTime": ISODate("2020-08-07T11:09:23.663Z"),

"appliedOpTime" : {

"ts": Timestamp(1596798563,1),

"t": NumberLong(1)

"durableOpTime" : {

"ts": Timestamp(1596798563,1),

"t": NumberLong(1)

"lastAppliedWallTime": ISODate("2020-08-07T11:09:23.663Z"),

"lastDurableWallTime": ISODate("2020-08-07T11:09:23.663Z")

"lastStableRecoveryTimestamp": Timestamp(1596798513,1),

"lastStableCheckpointTimestamp": Timestamp(1596798513,1),

"electionCandidateMetrics" : {

"lastElectionReason":"electionTimeout",

"lastElectionDate": ISODate("2020-08-07T09:31:33.409Z"),

"electionTerm": NumberLong(1),

"lastCommittedOpTimeAtElection" : {

"ts": Timestamp(0,0),

"t": NumberLong(-1)

"lastSeenOpTimeAtElection" : {

"ts": Timestamp(1596792682,1),

"t": NumberLong(-1)

"numVotesNeeded":2,

"priorityAtElection":1,

"electionTimeoutMillis": NumberLong(10000),

"numCatchUpOps": NumberLong(0),

"newTermStartDate": ISODate("2020-08-07T09:31:33.444Z"),

"wMajorityWriteAvailabilityDate": ISODate("2020-08-07T09:31:34.050Z")

"members" : [

{

"_id":0,

"name":"192.168.128.208:27017",

"health":1,

"state":1,

"stateStr":"PRIMARY",

"uptime":5950,

"optime" : {

"ts": Timestamp(1596798563,1),

"t": NumberLong(1)

"optimeDate": ISODate("2020-08-07T11:09:23Z"),

"syncingTo":"",

"syncSourceHost":"",

"syncSourceId": -1,

"infoMessage":"",

"electionTime": Timestamp(1596792693,1),

"electionDate": ISODate("2020-08-07T09:31:33Z"),

"configVersion":1,

"self":true,

"lastHeartbeatMessage":"" },

{

"_id":1,

"name":"192.168.128.209:27017",

"health":1,

"state":2,

"stateStr":"SECONDARY",

"uptime":5882,

"optime" : {

"ts": Timestamp(1596798563,1),

"t": NumberLong(1)

"optimeDurable" : {

"ts": Timestamp(1596798563,1),

"t": NumberLong(1)

"optimeDate": ISODate("2020-08-07T11:09:23Z"),

"optimeDurableDate": ISODate("2020-08-07T11:09:23Z"),

"lastHeartbeat": ISODate("2020-08-07T11:09:23.672Z"),

"lastHeartbeatRecv": ISODate("2020-08-07T11:09:22.804Z"),

"pingMs": NumberLong(0),

"lastHeartbeatMessage":"",

"syncingTo":"192.168.128.208:27017",

"syncSourceHost":"192.168.128.208:27017",

"syncSourceId":0,

"infoMessage":"",

"configVersion":1 },

{

"_id":2,

"name":"192.168.128.209:28017",

"health":1,

"state":7,

"stateStr":"ARBITER",

"uptime":5882,

"lastHeartbeat": ISODate("2020-08-07T11:09:23.672Z"),

"lastHeartbeatRecv": ISODate("2020-08-07T11:09:22.952Z"),

"pingMs": NumberLong(0),

"lastHeartbeatMessage":"",

"syncingTo":"",

"syncSourceHost":"",

"syncSourceId": -1,

"infoMessage":"",

"configVersion":1 }

"ok":1,

"$clusterTime" : {

"clusterTime": Timestamp(1596798563,1),

"signature" : {

"hash": BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),

"keyId": NumberLong(0)

}

"operationTime": Timestamp(1596798563,1)

}

test1:PRIMARY>

3 修改为认证模式

为考虑安全性等，需要开启认证模式（需要通过用户名/密码方式登录）

3.1 创建用户

创建超级管理员账号

test1:PRIMARY> db.createUser({user:"root",pwd:"Root#123", roles: [{role:"root", db:"admin"}]})

Successfully added user: {

"user":"root",

"roles" : [

{

"role":"root",

"db":"admin" }

]

}

3.2 创建key文件

在主库上执行脚本生成key文件，然后将结拷贝到另外2个节点

[root@m1 mongodb]# cd /data/mongodb/27017/keyfile/[root@m1 keyfile]# openssl rand -base64756> mongo.key

[root@m1 keyfile]# chmod600mongo.key # 必须修改为600权限，否则无法启动

以上完成后，将文件复制到另外2个节点

3.3 修改配置文件

配置文件中添加如下内容，注意不同节点的文件路径

security:

authorization: enabled

clusterAuthMode: keyFile

keyFile: /data/mongodb/27017/keyfile/mongo.key

3.4 重启后并用认证模式登陆

# 关闭mongodb

[root@m1 keyfile]# /usr/local/mongodb/bin/mongod -f /data/mongodb/27017/etc/mongod.conf -shutdown

killing process with pid: 30675# 启动mongodb

[root@m1 keyfile]# /usr/local/mongodb/bin/mongod -f /data/mongodb/27017/etc/mongod.conf about to fork child process, waitinguntilserver is readyfor connections.

forked process: 2430child process started successfully, parent exiting

# 认证模式登陆

[root@m1 keyfile]#

[root@m1 keyfile]# /usr/local/mongodb/bin/mongo -u root -p'Root#123'--authenticationDatabase admin

至此，mongodb 副本集搭建完毕，你会了吗？

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