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
创建数据目录、日志目录等相关目录
[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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