测试ReplicaSets读写分离和故障转移

读写分离实现步骤：

从库能够进行查询就更好了，这样可以分担主库的大量的查询请求。

1） 先向主库中插入一条测试数据

rs1:PRIMARY> db.c1.insert({age:30});db.c1.insert({age:30});

WriteResult({ "nInserted" : 1 })

rs1:PRIMARY>  db.c1.find() db.c1.find()

{ "_id" : ObjectId("5791ef011f4c6277726192b1"), "age" : 30 }

rs1:PRIMARY>

2)在从库进行查询等操作

[root@node222 bin]#  ./mongo --port 28011

MongoDB shell version: 3.2.8

connecting to: 127.0.0.1:28011/test

rs1:SECONDARY> show collectionsshow collections

2016-07-22T18:02:47.038+0800 E QUERY    [thread1] Error: listCollections failed: {

"ok" : 0,

"errmsg" : "not authorized on test to execute command { listCollections: 1.0, filter: {} }",

"code" : 13

} :

_getErrorWithCode@src/mongo/shell/utils.js:25:13

DB.prototype._getCollectionInfosCommand@src/mongo/shell/db.js:773:1

DB.prototype.getCollectionInfos@src/mongo/shell/db.js:785:19

DB.prototype.getCollectionNames@src/mongo/shell/db.js:796:16

shellHelper.show@src/mongo/shell/utils.js:754:9

shellHelper@src/mongo/shell/utils.js:651:15

@(shellhelp2):1:1

rs1:SECONDARY>

当查询时报错了，说明是个从库，目前不能执行查询的操作。

3）让从库可以读，分担主库的压力

> db.getMongo().setSlaveOk()

> show collections还是不行，

> exit

查询官方手册https://docs.mongodb.org/manual/tutorial/enable-authentication/发现登录方式应该用

[root@node222 bin]# ./mongo --port 28011 -u "bbb" -p "bbb" --authenticationDatabase "admin"

MongoDB shell version: 3.2.8

connecting to: 127.0.0.1:28011/test

Server has startup warnings:

2016-07-22T17:36:41.302+0800 I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.

2016-07-22T17:36:41.302+0800 I CONTROL  [initandlisten]

2016-07-22T17:36:41.302+0800 I CONTROL  [initandlisten]

2016-07-22T17:36:41.302+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.

2016-07-22T17:36:41.302+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'

2016-07-22T17:36:41.302+0800 I CONTROL  [initandlisten]

2016-07-22T17:36:41.302+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.

2016-07-22T17:36:41.302+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'

2016-07-22T17:36:41.302+0800 I CONTROL  [initandlisten]

rs1:SECONDARY> show collectionsshow collections

2016-07-22T18:06:17.354+0800 E QUERY    [thread1] Error: listCollections failed: { "ok" : 0, "errmsg" : "not master and slaveOk=false", "code" : 13435 } :

_getErrorWithCode@src/mongo/shell/utils.js:25:13

DB.prototype._getCollectionInfosCommand@src/mongo/shell/db.js:773:1

DB.prototype.getCollectionInfos@src/mongo/shell/db.js:785:19

DB.prototype.getCollectionNames@src/mongo/shell/db.js:796:16

shellHelper.show@src/mongo/shell/utils.js:754:9

shellHelper@src/mongo/shell/utils.js:651:15

@(shellhelp2):1:1

rs1:SECONDARY> use adminuse admin

switched to db admin

rs1:SECONDARY> show dbsshow dbs

admin  0.000GB

local  0.000GB

rs1:SECONDARY> db.getMongo().setSlaveOk() db.getMongo().setSlaveOk()

rs1:SECONDARY> show collectionsshow collections

system.users

system.version

rs1:SECONDARY>

OK了。执行 db.getMongo().setSlaveOk() 可以将从库的查询功能打开。

故障转移测试：

复制集比传统的master-slave有改进的地方就是它可以进行故障的自动转移，如果我们停掉复制集中的一个成员，那么剩余的成员就会再自动选举一个成员，作为主库，如下所示。

我们将28010这个主库停掉，然后再看一下复制集的状态。

1） 杀掉28010端口的MongoDB

[root@node222 bin]#  ps aux | grep mongod

root     16629  0.3  0.4 783320 80124 ?        Sl   17:36   0:07 /usr/local/mongodb/bin/mongod --replSet rs1 --keyFile /data02/mongors/key/r0 --fork --port 28010 --dbpath /data02/mongors/data/r0 --logpath=/data02/mongors/log/r0.log --logappend

root     16666  0.3  0.4 778000 78904 ?        Sl   17:36   0:07 /usr/local/mongodb/bin/mongod --replSet rs1 --keyFile /data02/mongors/key/r1 --fork --port 28011 --dbpath /data02/mongors/data/r1 --logpath=/data02/mongors/log/r1.log --logappend

root     16703  0.3  0.4 778004 75068 ?        Sl   17:36   0:07 /usr/local/mongodb/bin/mongod --replSet rs1 --keyFile /data02/mongors/key/r2 --fork --port 28012 --dbpath /data02/mongors/data/r2 --logpath=/data02/mongors/log/r2.log --logappend

root     16825  0.0  0.1 225072 22800 pts/1    Sl+  17:39   0:00 /usr/local/mongodb/bin/mongo -port 28010

root     17539  0.0  0.0 110216   900 pts/0    R+   18:12   0:00 grep --color=auto mongod

[root@node222 bin]# kill -9 16629

[root@node222 bin]#  ps aux | grep mongod

root     16666  0.3  0.4 778000 79056 ?        Sl   17:36   0:07 /usr/local/mongodb/bin/mongod --replSet rs1 --keyFile /data02/mongors/key/r1 --fork --port 28011 --dbpath /data02/mongors/data/r1 --logpath=/data02/mongors/log/r1.log --logappend

root     16703  0.3  0.4 778004 75200 ?        Sl   17:36   0:07 /usr/local/mongodb/bin/mongod --replSet rs1 --keyFile /data02/mongors/key/r2 --fork --port 28012 --dbpath /data02/mongors/data/r2 --logpath=/data02/mongors/log/r2.log --logappend

root     16825  0.0  0.1 225072 22800 pts/1    Sl+  17:39   0:00 /usr/local/mongodb/bin/mongo -port 28010

root     17569  0.0  0.0 110216   904 pts/0    R+   18:13   0:00 grep --color=auto mongod

[root@node222 bin]#

2) 查看复制集状态

[root@node222 mongodb]#  /usr/local/mongodb/bin/mongo -port 28011

MongoDB shell version: 3.2.8

connecting to: 127.0.0.1:28011/test

rs1:SECONDARY> rs.status();rs.status();//又是权限问题

{

"ok" : 0,

"errmsg" : "not authorized on admin to execute command { replSetGetStatus: 1.0 }",

"code" : 13

}

rs1:SECONDARY> use adminuse admin

switched to db admin

rs1:SECONDARY> db.auth('bbb','bbb')db.auth('bbb','bbb')

1

rs1:SECONDARY>  rs.status(); rs.status();

{

"set" : "rs1",

"date" : ISODate("2016-07-22T10:15:14.194Z"),

"myState" : 2,

"term" : NumberLong(2),

"syncingTo" : "localhost:28012",

"heartbeatIntervalMillis" : NumberLong(2000),

"members" : [

{

"_id" : 0,

"name" : "localhost:28010",

"health" : 0,

"state" : 8,

"stateStr" : "(not reachable/healthy)",

"uptime" : 0,

"optime" : {

"ts" : Timestamp(0, 0),

"t" : NumberLong(-1)

},

"optimeDate" : ISODate("1970-01-01T00:00:00Z"),

"lastHeartbeat" : ISODate("2016-07-22T10:15:14.054Z"),

"lastHeartbeatRecv" : ISODate("2016-07-22T10:13:10.712Z"),

"pingMs" : NumberLong(0),

   "lastHeartbeatMessage" : "Connection refused",

"configVersion" : -1

},

{

"_id" : 1,

"name" : "localhost:28011",

"health" : 1,

"state" : 2,

"stateStr" : "SECONDARY",

"uptime" : 2313,

"optime" : {

"ts" : Timestamp(1469182400, 2),

"t" : NumberLong(2)

},

"optimeDate" : ISODate("2016-07-22T10:13:20Z"),

"syncingTo" : "localhost:28012",

"configVersion" : 1,

"self" : true

},

{

"_id" : 2,

"name" : "localhost:28012",

"health" : 1,

"state" : 1,

     "stateStr" : "PRIMARY",

"uptime" : 2097,

"optime" : {

"ts" : Timestamp(1469182400, 2),

"t" : NumberLong(2)

},

"optimeDate" : ISODate("2016-07-22T10:13:20Z"),

"lastHeartbeat" : ISODate("2016-07-22T10:15:13.010Z"),

"lastHeartbeatRecv" : ISODate("2016-07-22T10:15:12.593Z"),

"pingMs" : NumberLong(0),

"electionTime" : Timestamp(1469182400, 1),

"electionDate" : ISODate("2016-07-22T10:13:20Z"),

"configVersion" : 1

}

],

"ok" : 1

}

rs1:SECONDARY>

可以看到28010这个端口的MongoDB出现了异常，而系统自动选举了 28012 这个端口为主，所以这样的故障处理机制，能讲系统的稳定性大大提高。