mongodb副本集介绍、mongodb副本集搭建、 mongodb副本集测试
mongodb副本集介绍
- MongoDB早期版本使用master-slave，一主一从和MySQL主从基本是一致的，但salve在此架构中为只读，当主库宕机后，从库不能自动切换为主.
- 目前已经淘汰master-salve模式，改成副本集，副本集架构也是为了实现MongoDB的高可用，这种模式下有一个主（primary），和多个从（secondary）只读，支持他们设置权重，当主宕机后，权重最高的从切换为主.
- 在此架构中还能够创建一个仲裁（arbiter）的角色，它只负责裁决，而不存储数据.
- 在此架构中读写数据都是在主上，要想实现负载均衡的目的须要手动指定读库的目标server.
MongoDB副本集架构图
原理很简单一个primary，secondary至少是一个，也能够是多个secondary，除了多个secondary以外，还能够加一个Arbiter，Arbiter叫作仲裁，当Primary宕机后，Arbiter能够很准确的告知Primary宕掉了，但可能Primary认为本身没有宕掉，这样的话就会出现脑裂，为了防止脑裂就增长了Arbiter这个角色，尤为是数据库坚定不能出现脑裂的状态，脑裂会致使数据会紊乱，数据一旦紊乱恢复就很是麻烦.linux
变迁图
说明：Primary宕机后，其中secondary就成为一个新的Primary，另一个secondary依然是secondary的角色. 对于MySQL主历来讲，即便作一主多从，万一master宕机后，可让从成为新的主，但这过程是须要手动的更改的. 可是在MongoDB副本集架构当中呢，它彻底都是自动的，rimary宕机后，其中secondary就成为一个新的Primary，另一个secondary能够自动识别新的primary.mongodb
mongodb副本集搭建
准备三台机器: 192.168.193.130 (primary)
192.168.193.131 (secondary)
192.168.193.132 (secondary)
三台机器都须要安装MongoDB，primary已安装过，两台secondary须要安装，因步骤同样，在此不作演示.shell
编辑三台机器的配置文件
[root@aminglinux-130 ~]# vim /etc/mongod.conf数据库
# network interfaces net: port: 27017 bindIp: 127.0.0.1,192.168.193.130 # Listen to local interface only, comment to listen on all interfaces. "/etc/mongod.conf" 44L, 784C
说明:作副本集bindIp 要监听本机IP和内网IPvim
#replication: //把#去掉，并增两行 replication: oplogSizeMB: 20 //前面两个空格 replSetName；aminglinux //定义副本集的名字 前面两个空格
重启MongoDB服务:bash
[root@aminglinux-130 ~]# systemctl restart mongod架构
启动从主机app
[root@aminglinux-131 ~]# vim /etc/mongod.conf
负载均衡
net: port: 27017 bindIp: 127.0.0.1,192.168.193.131 # Listen to local interface only, comment to listen on all interfaces.
说明:作副本集bindIp 要监听本机IP和内网IPspa
#replication: //把#去掉，并增两行 replication: oplogSizeMB: 20 replSetName: aminglinux //定义副本集的名字
重启MongoDB服务:
[root@aminglinux-131 ~]# systemctl restart mongod
[root@aminglinux-131 ~]# ps aux |grep mongod mongod 3111 2.2 3.9 1018232 39316 ? Sl 16:23 0:21 /usr/bin/mongod -f /etc/mongod.conf root 3282 0.0 0.0 112704 660 pts/0 R+ 16:39 0:00 grep --color=auto mongod
启动从主机
[root@aminglinux-132 ~]# vim /etc/mongod.conf
#replication: //把#去掉，并增两行 replication: oplogSizeMB: 20 replSetName: aminglinux //定义副本集的名字
[root@aminglinux-132 ~]# systemctl restart mongod
[root@aminglinux-132 ~]# ps aux |grep mongod mongod 3246 60.0 3.7 1018232 37532 ? Sl 16:44 0:42 /usr/bin/mongod -f /etc/mongod.conf root 3292 0.0 0.0 112720 980 pts/0 R+ 16:45 0:00 grep --color=auto mongod
链接MongoDB --Primary机器
[root@aming-130 ~]# mongo MongoDB shell version v3.4.9 connecting to: mongodb://127.0.0.1:27017 MongoDB server version: 3.4.9 Server has startup warnings: 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten] 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten] ** WARNING: Access control is not enabled for the database. 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten] ** Read and write access to data and configuration is unrestricted. 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten] 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten] 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'. 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never' 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten] 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'. 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never' 2017-10-20T17:18:53.740+0800 I CONTROL [initandlisten]
置副本集
说明:在哪台机器上执行这一步，那么哪台机器就会成为primary
> config={_id:"aminglinux",members:[{_id:0,host:"192.168.193.130:27017"},{_id:1,host:"192.168.193.131:27017"},{_id:2,host:"192.168.193.132:27017"}]}
{
"_id" : "aminglinux",
"members" : [
{
"_id" : 0,
"host" : "192.168.193.130:27017"
},
{
"_id" : 1,
"host" : "192.168.193.131:27017"
},
{
"_id" : 2,
"host" : "192.168.193.132:27017"
}
]
}
>
config={_id:"aminglinux" --> aminglinux(副本集的名字)
members --> 指定成员
rs.initiate(config) -->初始化
> rs.initiate()？
{ "ok" : 1 }
rs.status() -->查看副本集状态
说明：能够看到192.168.193.130 显示："stateStr" : "PRIMARY"
192.168.193.131和192.168.193.132 分别显示： "stateStr" : "SECONDARY"
aminglinux:OTHER> rs.status()
{
"set" : "aminglinux",
"date" : ISODate("2019-05-14T10:54:40.893Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1557831277, 1),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1557831277, 1),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1557831277, 1),
"t" : NumberLong(1)
}
},
"members" : [
{
"_id" : 0,
"name" : "192.168.193.130:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 319,
"optime" : {
"ts" : Timestamp(1557831277, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-05-14T10:54:37Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1557831175, 2),
"electionDate" : ISODate("2019-05-14T10:52:55Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
}
],
"ok" : 1
}
annalinux:PRIMARY> rs.status()
{
"set" : "annalinux",
"date" : ISODate("2019-05-14T11:05:12.553Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1557831909, 1),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1557831909, 1),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1557831909, 1),
"t" : NumberLong(1)
}
},
"members" : [
{
"_id" : 0,
"name" : "192.168.193.131:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 953,
"optime" : {
"ts" : Timestamp(1557831909, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-05-14T11:05:09Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "",
"electionTime" : Timestamp(1557831527, 2),
"electionDate" : ISODate("2019-05-14T10:58:47Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
}
],
"ok" : 1
}
annalinux:OTHER> rs.status()
{
"set" : "annalinux",
"date" : ISODate("2019-05-14T11:06:48.154Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1557832006, 1),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1557832006, 1),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1557832006, 1),
"t" : NumberLong(1)
}
},
"members" : [
{
"_id" : 0,
"name" : "192.168.193.132:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 654,
"optime" : {
"ts" : Timestamp(1557832006, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2019-05-14T11:06:46Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1557832004, 2),
"electionDate" : ISODate("2019-05-14T11:06:44Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
}
],
"ok" : 1
}