MongoDB 副本集自动复制 Replica Set
MongoDB部署实验系列文章，MongoDB做为NoSQL数据库，最近几年持续升温，越来越多的企业都开始尝试用MongoDB代替原有Database做一些事情。MongoDB也在集群，分片，复制上也有相当不错的的表现。我通过将做各种MongoDB的部署实验进行介绍。
第二篇 MongoDB 副本集自动复制 Replica Set，分为7个部分
1.初始化文件目录
2.启动副本集 Replica Set
3.模拟 PRIMARY失败，SECONDARY自动切换
4.修复失败节点
5.恢复失败节点，补充到SECONDARY
6.删除一个Replica Set节点
7.新增加一个Replica Set节点
系统环境介绍：
Ubuntu 12.04. LTS 64bit Server
初始化文件目录
~ pwd
/home/conan/dbs
~ mkdir node1 node2 node3
~ ls -l
drwxrwxr-x 2 conan conan 4096 May 31 14:21 node1
drwxrwxr-x 2 conan conan 4096 May 31 14:21 node2
drwxrwxr-x 2 conan conan 4096 May 31 14:21 node3
启动副本集 Replica Set
启动node1,node2,node3
mongod --dbpath /home/conan/dbs/node1 --port 10001 --replSet blort --nojournal --fork --logpath /home/conan/dbs/node1.log
mongod --dbpath /home/conan/dbs/node2 --port 10002 --replSet blort --nojournal --fork --logpath /home/conan/dbs/node2.log
mongod --dbpath /home/conan/dbs/node3 --port 10003 --replSet blort --nojournal --fork --logpath /home/conan/dbs/node3.log
副本集初始化
~ mongo localhost:10001
MongoDB shell version: 2.4.3
connecting to: localhost:10001/test
> rs.initiate({_id:"blort",members:[
{_id:1,host:"localhost:10001"},
{_id:2,host:"localhost:10002"},
{_id:3,host:"localhost:10003"},
]})
{
"info" : "Config now saved locally. Should come online in about a minute.",
"ok" : 1
}
查看日志信息:node1变选为PRIMARY,node2,node3分别是2个SECONDARY
Fri May 31 14:26:44.728 [conn2] ******
Fri May 31 14:26:44.728 [conn2] replSet info saving a newer config version to local.system.replset
Fri May 31 14:26:44.741 [conn2] replSet saveConfigLocally done
Fri May 31 14:26:44.741 [conn2] replSet replSetInitiate config now saved locally. Should come online in about a minute.
Fri May 31 14:26:44.741 [conn2] command admin.$cmd command: { replSetInitiate: { _id: "blort", members: [ { _id: 1.0, host: "localhost:10001" }, { _id: 2.0, host: "localhost:10002" }, { _id: 3.0, host: "localhost:10003" } ] } } ntoreturn:1 keyUpdates:0 locks(micros) W:646741 reslen:112 652ms
Fri May 31 14:26:53.682 [rsStart] replSet I am localhost:10001
Fri May 31 14:26:53.682 [rsStart] replSet STARTUP2
Fri May 31 14:26:53.683 [rsHealthPoll] replSet member localhost:10002 is up
Fri May 31 14:26:53.684 [rsHealthPoll] replSet member localhost:10003 is up
Fri May 31 14:26:54.285 [initandlisten] connection accepted from 127.0.0.1:46469 #3 (3 connections now open)
Fri May 31 14:26:54.683 [rsSync] replSet SECONDARY
用mongo客户端查看设置
node1连接
~ mongo localhost:10001
MongoDB shell version: 2.4.3
connecting to: localhost:10001/test
blort:PRIMARY> rs.status()
{
"set" : "blort",
"date" : ISODate("2013-05-31T06:34:12Z"),
"myState" : 1,
"members" : [
{
"_id" : 1,
"name" : "localhost:10001",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 659,
"optime" : {
"t" : 1369981604,
"i" : 1
},
"optimeDate" : ISODate("2013-05-31T06:26:44Z"),
"self" : true
},
{
"_id" : 2,
"name" : "localhost:10002",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 439,
"optime" : {
"t" : 1369981604,
"i" : 1
},
"optimeDate" : ISODate("2013-05-31T06:26:44Z"),
"lastHeartbeat" : ISODate("2013-05-31T06:34:11Z"),
"lastHeartbeatRecv" : ISODate("1970-01-01T00:00:00Z"),
"pingMs" : 0,
"syncingTo" : "localhost:10001"
},
{
"_id" : 3,
"name" : "localhost:10003",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 439,
"optime" : {
"t" : 1369981604,
"i" : 1
},
"optimeDate" : ISODate("2013-05-31T06:26:44Z"),
"lastHeartbeat" : ISODate("2013-05-31T06:34:11Z"),
"lastHeartbeatRecv" : ISODate("1970-01-01T00:00:00Z"),
"pingMs" : 0,
"syncingTo" : "localhost:10001"
}
],
"ok" : 1
}
node2连接
~ mongo localhost:10002
MongoDB shell version: 2.4.3
connecting to: localhost:10002/test
blort:SECONDARY>
在primary插入数据：
~ mongo localhost:10001
MongoDB shell version: 2.4.3
connecting to: localhost:10001/test
blort:PRIMARY> show dbs
local 1.078125GB
blort:PRIMARY> use fensme
switched to db fensme
blort:PRIMARY> db.user.insert({uid:10001})
blort:PRIMARY> db.user.find()
{ “_id” : ObjectId(“51a8454813321f05df62a8c8″), “uid” : 10001 }
连接node2，SECONDARY查询数据
~ mongo localhost:10002
MongoDB shell version: 2.4.3
connecting to: localhost:10002/test
blort:SECONDARY> show dbs
fensme 0.203125GB
local 1.078125GB
blort:SECONDARY> use fensme
switched to db fensme
blort:SECONDARY> show collections
Fri May 31 14:39:22.276 JavaScript execution failed: error: { “$err” : “not master and slaveOk=false”, “code” : 13435 } at src/mongo/shell/query.js:L128
blort:SECONDARY> db.user.find()
error: { “$err” : “not master and slaveOk=false”, “code” : 13435 }
提示是不是master/slave的结构，SECONDARY不许允查询。
模拟 PRIMARY失败，SECONDARY自动切换
ps -aux|grep mongod
conan 5110 0.4 2.1 1723616 44608 ? Sl 14:23 0:05 mongod --dbpath /home/conan/dbs/node1 --port 10001 --replSet blort --nojournal --fork --logpath /home/conan/dbs/node1.log
conan 5173 0.4 2.2 1693812 45960 ? Sl 14:24 0:04 mongod --dbpath /home/conan/dbs/node2 --port 10002 --replSet blort --nojournal --fork --logpath /home/conan/dbs/node2.log
conan 5218 0.4 2.2 1692800 45548 ? Sl 14:24 0:04 mongod --dbpath /home/conan/dbs/node3 --port 10003 --replSet blort --nojournal --fork --logpath /home/conan/dbs/node3.log
kill -9 5110
ps -aux|grep mongod
conan 5173 0.4 2.2 1703048 46096 ? Sl 14:24 0:04 mongod --dbpath /home/conan/dbs/node2 --port 10002 --replSet blort --nojournal --fork --logpath /home/conan/dbs/node2.log
conan 5218 0.4 2.2 1702036 45696 ? Sl 14:24 0:04 mongod --dbpath /home/conan/dbs/node3 --port 10003 --replSet blort --nojournal --fork --logpath /home/conan/dbs/node3.log
连接node2，SECONDARY查询节点重新选举
~ mongo localhost:10002
MongoDB shell version: 2.4.3
connecting to: localhost:10002/test
blort:SECONDARY> rs.status()
{
“set” : “blort”,
“date” : ISODate(“2013-05-31T06:42:51Z”),
“myState” : 2,
“syncingTo” : “localhost:10003″,
“members” : [
{
"_id" : 1,
"name" : "localhost:10001",
"health" : 0,
"state" : 8,
"stateStr" : "(not reachable/healthy)",
"uptime" : 0,
"optime" : {
"t" : 1369982280,
"i" : 1
},
"optimeDate" : ISODate("2013-05-31T06:38:00Z"),
"lastHeartbeat" : ISODate("2013-05-31T06:42:51Z"),
"lastHeartbeatRecv" : ISODate("1970-01-01T00:00:00Z"),
"pingMs" : 0
},
{
"_id" : 2,
"name" : "localhost:10002",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1088,
"optime" : {
"t" : 1369982280,
"i" : 1
},
"optimeDate" : ISODate("2013-05-31T06:38:00Z"),
"errmsg" : "syncing to: localhost:10003",
"self" : true
},
{
"_id" : 3,
"name" : "localhost:10003",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 946,
"optime" : {
"t" : 1369982280,
"i" : 1
},
"optimeDate" : ISODate("2013-05-31T06:38:00Z"),
"lastHeartbeat" : ISODate("2013-05-31T06:42:51Z"),
"lastHeartbeatRecv" : ISODate("1970-01-01T00:00:00Z"),
"pingMs" : 0,
"syncingTo" : "localhost:10001"
}
],
“ok” : 1
}
查看结果：
localhost:10001 ： not reachable/healthy
localhost:10002： SECONDARY
localhost:10003： PRIMARY
连接node3, localhost:10003查看数据
mongo localhost:10003
MongoDB shell version: 2.4.3
connecting to: localhost:10003/test
blort:PRIMARY> show dbs
fensme 0.203125GB
local 1.078125GB
blort:PRIMARY> use fensme
switched to db fensme
blort:PRIMARY> show collections
system.indexes
user
blort:PRIMARY> db.user.find()
{ “_id” : ObjectId(“51a8454813321f05df62a8c8″), “uid” : 10001 }
node1失效后，node3被选为了PRIMARY，数据在node3可以查询到。
修复失败节点
直接重启node1，启动失败：
~ mongod --dbpath /home/conan/dbs/node1 --port 10001 --replSet blort --nojournal --fork --logpath /home/conan/dbs/node1_restart.log
MongoDB starting : pid=8544 port=10001 dbpath=/home/conan/dbs/node1 64-bit host=u1
Fri May 31 14:49:37.280 [initandlisten] db version v2.4.3
Fri May 31 14:49:37.280 [initandlisten] git version: fe1743177a5ea03e91e0052fb5e2cb2945f6d95f
Fri May 31 14:49:37.280 [initandlisten] build info: Linux ip-10-2-29-40 2.6.21.7-2.ec2.v1.2.fc8xen #1 SMP Fri Nov 20 17:48:28 EST 2009 x86_64 BOOST_LIB_VERSION=1_49
Fri May 31 14:49:37.280 [initandlisten] allocator: tcmalloc
Fri May 31 14:49:37.280 [initandlisten] options: { dbpath: "/home/conan/dbs/node1", fork: true, logpath: "/home/conan/dbs/node1_restart.log", nojournal: true, port: 10001, replSet: "blort" }
**************
Unclean shutdown detected.
Please visit http://dochub.mongodb.org/core/repair for recovery instructions.
*************
Fri May 31 14:49:37.281 [initandlisten] exception in initAndListen: 12596 old lock file, terminating
Fri May 31 14:49:37.281 dbexit:
Fri May 31 14:49:37.281 [initandlisten] shutdown: going to close listening sockets...
Fri May 31 14:49:37.281 [initandlisten] shutdown: going to flush diaglog...
Fri May 31 14:49:37.281 [initandlisten] shutdown: going to close sockets...
Fri May 31 14:49:37.281 [initandlisten] shutdown: waiting for fs preallocator...
Fri May 31 14:49:37.281 [initandlisten] shutdown: closing all files...
Fri May 31 14:49:37.281 [initandlisten] closeAllFiles() finished
Fri May 31 14:49:37.281 dbexit: really exiting now
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