华双成,医科大学总医院,陈德荣调任天津
一、replica set 集群分为两种架构：
接下来就以3台服务器为例，部署具有仲裁的框架。
| ip地址 | 操作系统版本 | mongodb版本 | 端口 | 功能 |
| 10.10.18.10 | centos7.5 | 4.0 | 27017 | primary |
| 10.10.18.11 | centos7.5 | 4.0 | 27017 | secondary |
| 10.10.18.12 | centos7.5 | 4.0 | 27017 | arbiter |
二、安装部署（请访问 "mongodb安装"）
primary的配置文件：
我要评论systemlog:
destination: file
path: "/data/mongodb/log/mongod.log"
logappend: true
storage:
dbpath: "/data/mongodb/data"
journal:
enabled: true
wiredtiger:
engineconfig:
cachesizegb: 2
processmanagement:
fork: true
pidfilepath: "/data/mongodb/pid/m.pid"
net:
bindip: 10.10.18.10
port: 27017
replication:
replsetname: "rs0"
secondary的配置文件
systemlog:
destination: file
path: "/data/mongodb/log/mongod.log"
logappend: true
storage:
dbpath: "/data/mongodb/data"
journal:
enabled: true
wiredtiger:
engineconfig:
cachesizegb: 2
processmanagement:
fork: true
pidfilepath: "/data/mongodb/pid/m.pid"
net:
bindip: 10.10.18.11
port: 27017
replication:
replsetname: "rs0"
arbiter的配置文件
systemlog:
destination: file
path: "/data/mongodb/log/mongod.log"
logappend: true
storage:
dbpath: "/data/mongodb/data"
journal:
enabled: true
wiredtiger:
engineconfig:
cachesizegb: 2
processmanagement:
fork: true
pidfilepath: "/data/mongodb/pid/m.pid"
net:
bindip: 10.10.18.12
port: 27017
replication:
replsetname: "rs0"
启动三台服务器上的mongdb
mongod -f /data/mongodb/mongod.conf
三、配置replica set
登录三台服务器中任意一台，登录mongo
mongo --host 10.10.18.10
>cfg={ _id:"rs0",members:[{_id:0,host:'10.10.18.10:27017',priority:1},{_id:1,host:'10.10.18.11:27017',priority:1},{_id:2,host:'10.10.18.12:27017',arbiteronly:true}] };
>rs.initiate(cfg)
查看replica set配置
> rs.conf()
{
"_id" : "rs0",
"version" : 1,
"protocolversion" : numberlong(1),
"writeconcernmajorityjournaldefault" : true,
"members" : [
{
"_id" : 0,
"host" : "10.10.18.10:27017",
"arbiteronly" : false,
"buildindexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {
},
"slavedelay" : numberlong(0),
"votes" : 1
},
{
"_id" : 1,
"host" : "10.10.18.11:27017",
"arbiteronly" : false,
"buildindexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {
},
"slavedelay" : numberlong(0),
"votes" : 1
},
{
"_id" : 2,
"host" : "10.10.18.12:27017",
"arbiteronly" : true,
"buildindexes" : true,
"hidden" : false,
"priority" : 0,
"tags" : {
},
"slavedelay" : numberlong(0),
"votes" : 1
}
],
"settings" : {
"chainingallowed" : true,
"heartbeatintervalmillis" : 2000,
"heartbeattimeoutsecs" : 10,
"electiontimeoutmillis" : 10000,
"catchuptimeoutmillis" : -1,
"catchuptakeoverdelaymillis" : 30000,
"getlasterrormodes" : {
},
"getlasterrordefaults" : {
"w" : 1,
"wtimeout" : 0
},
"replicasetid" : objectid("5cff76e5e57e23a5bc7054e2")
}
}
四、验证replica set
在primary中插入数据
rs0:primary> show dbs
admin 0.000gb
config 0.000gb
local 0.000gb
rs0:primary> db.users.insertone(
... {
... name:"sue",
... age: 26,
... status:"pending"
... })
{
"acknowledged" : true,
"insertedid" : objectid("5cff79e8993e70290a081d04")
}
rs0:primary> db.users.find()
{ "_id" : objectid("5cff79e8993e70290a081d04"), "name" : "sue", "age" : 26, "status" : "pending" }
在secondary中，默认是不允许读
rs0:secondary> db.users.find()
error: error: {
"operationtime" : timestamp(1560247181, 1),
"ok" : 0,
"errmsg" : "not master and slaveok=false",
"code" : 13435,
"codename" : "notmasternoslaveok",
"$clustertime" : {
"clustertime" : timestamp(1560247181, 1),
"signature" : {
"hash" : bindata(0,"aaaaaaaaaaaaaaaaaaaaaaaaaaa="),
"keyid" : numberlong(0)
}
}
}
五、故障模拟
停止primary上的mongo进程，在secondary上登录mongo查看
mongo --host 10.10.18.11
rs0:primary> db.users.find() { "_id" : objectid("5cff79e8993e70290a081d04"), "name" : "sue", "age" : 26, "status" : "pending" }
发现原secondary变成primary，并且可以进行查询。
开启原primary服务器上的mongo进程，该服务器变成了secondary。
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