在nosql数据库里,大部分的查询都是键值对（key、value）的方式.MongoDB是一个介于关系数据库和非关系数据库之间的产品,是非关系数据库当中最像关系数据库的.支持类似于面向对象的查询语言,几乎可以实现类似关系数据库单表查询的绝大部分功能,而且还支持对数据建立索引.所以这个非常方便,我们可以用sql操作MongoDB,从关系型数据库迁移过来,开发人员学习成本会大大减少.如果再对底层的sql API做一层封装,开发基本可以感觉不到mongodb和关系型数据库的区别.同样MongoDB也是号称自己能够快速搭建一个高可用可扩展的的分布式集群,网上有很多搭建的文章,在我们搭建的时候还需要查找修改很多东西,所以把自己实战的步骤记录下来以备忘.我们看看如何一步一步搭建这个东东.

一、mongodb单实例.这种配置只适合简易开发时使用,生产使用不行,因为单节点挂掉整个数据业务全挂,如下图.
虽然不能生产使用,但这个模式可以快速搭建启动,并且能够用mongodb的命令操作数据库.下面列出在linux下安装单节点mongodb的步骤

二、主从模式.使用mysql数据库时大家广泛用到,采用双机备份后主节点挂掉了后从节点可以接替主机继续服务.所以这种模式比单节点的高可用性要好很多.
下面看一下怎么一步步搭建一个mongodb的主从复制节点:
1、准备两台机器 43.241.222.110 和 42.96.194.60. 43.241.222.110 当作主节点, 42.96.194.60作为从节点.
2、分别下载 mongodb 安装程序包.在 43.241.222.110 上建立文件夹 /home/data/mongodb,42.96.194.60 建立文件夹 /home/data/mongodb
两台MongoDB服务器的配置文件均为 /etc/mongod.cnf

storage:
    dbPath: "/data/home/data/mongodb"
    engine: wiredTiger
    wiredTiger:
        engineConfig:
            cacheSizeGB: 20
        collectionConfig:
            blockCompressor: snappy

systemLog:
   destination: file
   path: "/var/log/mongodb/mongod.log"
   logAppend: true

processManagement:
    fork: true

net:
    #bindIp: 127.0.0.1,43.241.222.110,42.96.194.60  不能绑定外网访问ip,局域网的貌似可以,只能在iptable设定允许指定ip访问27017
    #bindIp: 0.0.0.0
    port: 27017
    # Enable the HTTP interface (Defaults to port 28017).
    http:
        enabled: false

3、在43.241.222.110启动mongodb主节点程序.注意后面的这个 “-master”参数,标示主节点.启动主节点

sudo mongod -f /etc/mongod.cnf -master

4、在42.96.194.60启动 mongodb 从节点程序.关键配置,指定主节点ip地址和端口 -source 43.241.222.110:27017 和标示从节点 -slave 参数.

sudo mongod -f /etc/mongod.cnf -slave -source 43.241.222.110:27017

输出日志如下,成功！

#日志显示从节点从主节点同步复制数据

[replslave] repl: from host:43.241.222.110:27017

配置完Mongo主从复制后开始测试主从复制.

在主节点上连接到终端:

mongo 127.0.0.1

#建立test 数据库.

use test;

往testdb表插入数据.

> db.testdb.insert({"test1":"testval1"})

查询testdb数据看看是否成功.

> db.testdb.find();
{ "_id" : ObjectId("5284e5cb1f4eb215b2ecc463"), "test1" : "testval1" }

检查从主机的数据.

mongo 127.0.0.1

查看当前数据库.

> show dbs;
  local   0.203125GB
  test    0.203125GB

use test;
db.testdb.find();
{ "_id" : ObjectId("5284e5cb1f4eb215b2ecc463"), "test1" : "testval1" }

查询后数据已经同步过来了.再看看日志,发现从主机确实从主机同步了数据.

查看服务状态

> db.printReplicationInfo();
this is a slave, printing slave replication info.
source:   43.241.222.110:27017
  syncedTo: Sun Nov 17 2013 16:04:02 GMT+0800 (CST) = -54 secs ago (-0.01hrs)

到此主从结构的mongodb搭建好了.

参考 MongoDB学习札记第六篇之主从复制

MongoDB 3.0 复制集升级操作以及坑

问题分析

进入MongoShell执行以下命令

>show dbs

提示以下错误

E QUERY Error: listDatabases failed: 
        { "note" : "from execCommand", "ok" : 0, "errmsg" : "not master" }
at Error (<anonymous>)

查看mongo状态

> rs.status()
{ "ok" : 0, "errmsg" : "not running with --replSet", "code" : 76 }

每次登陆mongoShell后都需要执行以下命令

> rs.slaveOK()
2015-09-24T17:03:16.528+0800 E QUERY    TypeError: Object function () { return "try rs.help()"; } has no method 'slaveOK'    at (shell):1:4

参考 MongoDB 3.0 复制集升级操作以及坑 http://dev.guanghe.tv/2015/05/mongdb3-upgrade-bug.html

//查看状态

> rs.status()
{ "ok" : 0, "errmsg" : "not running with --replSet", "code" : 76 }

查看运行时配置

> use admin
switched to db admin
> db.runCommand("getCmdLineOpts")
{
    "argv" : [
        "mongod",
        "-f",
        "/etc/mongod.cnf",
        "-slave",
        "-source",
        "43.241.222.110:27017"
    ],
    "parsed" : {
        "config" : "/etc/mongod.cnf",
        "net" : {
            "http" : {
                "enabled" : false
            },
            "port" : 27017
        },
        "processManagement" : {
            "fork" : true
        },
        "slave" : true,
        "source" : "43.241.222.110:27017",
        "storage" : {
            "dbPath" : "/data/home/data/mongodb",
            "engine" : "wiredTiger",
            "wiredTiger" : {
                "collectionConfig" : {
                    "blockCompressor" : "snappy"
                },
                "engineConfig" : {
                    "cacheSizeGB" : 20
                }
            }
        },
        "systemLog" : {
            "destination" : "file",
            "logAppend" : true,
            "path" : "/var/log/mongodb/mongod.log"
        }
    },
    "ok" : 1
}

2016-01-10

Title

MongoDB 复制集

参考 MongoDB学习札记第八篇之Replica Set 实战
参考 MongoDB 3.0 复制集集群搭建及安全认证实践
参考 MongoDB 3.0 WT引擎参考配置文件
参考 MongoDB 副本集的原理、搭建、应用

准备三台mongo服务器分别为 43.241.222.110 42.96.194.60 和 45.63.50.67 搭建复制集

如果对于怎么安装Mongodb还不清楚的同学可以查看我之前的学习札记

三台MongoDB服务器的配置文件均为 /etc/mongod.cnf

storage:
    dbPath: "/data/home/data/RSMongoDB"
    engine: wiredTiger
    wiredTiger:
        engineConfig:
            cacheSizeGB: 20
        collectionConfig:
            blockCompressor: snappy

systemLog:
   destination: file
   path: "/var/log/mongodb/mongod.log"
   logAppend: true

processManagement:
    fork: true

net:
    #bindIp: 127.0.0.1,43.241.222.110,42.96.194.60  不能绑定外网访问ip,局域网的貌似可以,只能在iptable设定允许指定ip访问27017
    #bindIp: 0.0.0.0
    port: 27017
    # Enable the HTTP interface (Defaults to port 28017).
    http:
        enabled: false

第一步:

在三台机器上分别运行（都要运行）

root@ubuntu:/usr/local/mongodb#mongod -f /etc/mongod.cnf --replSet CoamReSet

注意这里的 —replSet 参数指定了副本集的名称,每一个副本集都有一个唯一的名称.

等到三台机器都启动完了之后.使用mongo客户端登录其中一台mongod服务器.这里我登录到 43.241.222.110 这台机器

root@ubuntu:~# mongo

登录之后要切换到admin数据库,这样我们可以进行副本集的配置,具体怎么配置,代码如下:

> use admin
switched to db admin

定义副本集配置变量,这里的 _id:”repset” 和上面命令参数 “ –replSet repset” 要保持一样.

> config = {_id:"CoamReSet",members:[
         {_id:0,host:"43.241.222.110:27017","priority":1},
         {_id:1,host:"42.96.194.60:27017","priority":1},
         {_id:2,host:"45.63.50.67:27017","priority":0}]}

输出

{
    "_id" : "CoamReSet",
    "members" : [
        {
            "_id" : 0,
            "host" : "43.241.222.110:27017"
        },
        {
            "_id" : 1,
            "host" : "42.96.194.60:27017"
        },
        {
            "_id" : 2,
            "host" : "45.63.50.67:27017"
        }
    ]
}

初始化副本集配置

> rs.initiate(config);

输出成功

{ "ok" : 1 }

注意:新创建副本集必须要数据库没有数据,否则初始化会提示以下错误:

{
    "ok" : 0,
    "errmsg" : "'42.96.194.60:27017' has data already, cannot initiate set.",
    "code" : 110
}

先定义 config 的配置信息, 然后通过 rs.initiate(config) 方法,将配置信息初始化.这两个步骤完成之后就表示我们的副本集配置信息初始化完成了,在这个CoamReSet的副本集中我们定义了三台主机（注意在定义配置信息的时候指定的 _id 必须和我们启动mongod的时候指定的参数 —replSet 这个参数的值是一样的.）

过一会,mongodb就会帮我们选举出Primary节点和Secondary节点了.那在mongo客户端,我们可以通过 rs.status() 来查看副本集的状态信息

CoamReSet:SECONDARY> rs.status()
{
    "set" : "CoamReSet",
    "date" : ISODate("2015-10-01T09:45:34.924Z"),
    "myState" : 1,
    "members" : [
        {
            "_id" : 0,
            "name" : "43.241.222.110:27017",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 167,
            "optime" : Timestamp(1443692712, 1),
            "optimeDate" : ISODate("2015-10-01T09:45:12Z"),
            "electionTime" : Timestamp(1443692715, 1),
            "electionDate" : ISODate("2015-10-01T09:45:15Z"),
            "configVersion" : 1,
            "self" : true
        },
        {
            "_id" : 1,
            "name" : "42.96.194.60:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 21,
            "optime" : Timestamp(1443692712, 1),
            "optimeDate" : ISODate("2015-10-01T09:45:12Z"),
            "lastHeartbeat" : ISODate("2015-10-01T09:45:33.166Z"),
            "lastHeartbeatRecv" : ISODate("2015-10-01T09:45:33.564Z"),
            "pingMs" : 16,
            "configVersion" : 1
        },
        {
            "_id" : 2,
            "name" : "45.63.50.67:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 21,
            "optime" : Timestamp(1443692712, 1),
            "optimeDate" : ISODate("2015-10-01T09:45:12Z"),
            "lastHeartbeat" : ISODate("2015-10-01T09:45:32.949Z"),
            "lastHeartbeatRecv" : ISODate("2015-10-01T09:45:33.973Z"),
            "pingMs" : 183,
            "configVersion" : 1
        }
    ],
    "ok" : 1
}

其中name表示我么你的主机, health表示主机是否健康（0/1） , state（主节点(1)还是从节点(2),或者是不可达节点)

如果上面信息正常显示出来说明整个副本集群已经建立起来了.这时候我们来验证一下是否是真的能够自动备份数据,是否能够自动从失败中恢复,自动选举新的Primary节点.
这个实验我们这样来做:

先往 Primary 节点（43.241.222.110）插入数据,在 42.96.194.60 和 45.63.50.67 两台 Secondary 节点中查询数据,验证是否能够正常的同步机器.

先往 Primary 节点（43.241.222.110）插入数据

CoamReSet:PRIMARY> use test
switched to db test
CoamReSet:PRIMARY> show collections
CoamReSet:PRIMARY> db.guids.insert({"name":"replica set","author":"webinglin"})
WriteResult({ "nInserted" : 1 })
CoamReSet:PRIMARY> exit
bye

在 45.63.50.67 Secondary 节点中查询数据,验证是否能够正常的同步机器.

root@ubuntu:~# mongo --host 45.63.50.67
MongoDB shell version: 3.0.3
connecting to: 45.63.50.67:27017/test
Server has startup warnings:
2015-06-09T17:03:27.744-0700 I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not re                                      commended.
2015-06-09T17:03:27.744-0700 I CONTROL  [initandlisten]
2015-06-09T17:03:27.745-0700 I CONTROL  [initandlisten]
2015-06-09T17:03:27.745-0700 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2015-06-09T17:03:27.745-0700 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2015-06-09T17:03:27.745-0700 I CONTROL  [initandlisten]
CoamReSet:SECONDARY> show dbs
2015-06-09T17:13:49.138-0700 E QUERY    Error: listDatabases failed:{ "note" : "from execCommand", "ok" : 0, "errmsg" : "not master" }
    at Error (<anonymous>)
    at Mongo.getDBs (src/mongo/shell/mongo.js:47:15)
    at shellHelper.show (src/mongo/shell/utils.js:630:33)
    at shellHelper (src/mongo/shell/utils.js:524:36)
    at (shellhelp2):1:1 at src/mongo/shell/mongo.js:47
CoamReSet:SECONDARY> use test
switched to db test
CoamReSet:SECONDARY> db.guids.find()
Error: error: { "$err" : "not master and slaveOk=false", "code" : 13435 }
CoamReSet:SECONDARY> rs.slaveOk()
CoamReSet:SECONDARY> rs.slaveOk()
CoamReSet:SECONDARY> db.guids.find()
{ "_id" : ObjectId("557780ebd147e9391020860d"), "name" : "replica set", "author" : "webinglin" }
CoamReSet:SECONDARY> show collections()
2015-06-09T17:14:24.219-0700 E QUERY    Error: don't know how to show [collections()]
    at Error (<anonymous>)
    at shellHelper.show (src/mongo/shell/utils.js:733:11)
    at shellHelper (src/mongo/shell/utils.js:524:36)
    at (shellhelp2):1:1 at src/mongo/shell/utils.js:733
CoamReSet:SECONDARY> show collections
guids
system.indexes
CoamReSet:SECONDARY> exit
bye

在 42.96.194.60 Secondary 节点中查询数据,验证是否能够正常的同步机器.

root@ubuntu:~# mongo --host 42.96.194.60
MongoDB shell version: 3.0.3
connecting to: 42.96.194.60:27017/test
Server has startup warnings:
2015-06-09T17:03:11.647-0700 I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not re                                      commended.
2015-06-09T17:03:11.647-0700 I CONTROL  [initandlisten]
2015-06-09T17:03:11.647-0700 I CONTROL  [initandlisten]
2015-06-09T17:03:11.648-0700 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2015-06-09T17:03:11.648-0700 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2015-06-09T17:03:11.648-0700 I CONTROL  [initandlisten]
CoamReSet:SECONDARY> rs.slaveOk()
CoamReSet:SECONDARY> show dbs
local  1.078GB
test   0.078GB
CoamReSet:SECONDARY> use test
switched to db test
CoamReSet:SECONDARY> show collections
guids
system.indexes
CoamReSet:SECONDARY> db.guids.find()
{ "_id" : ObjectId("557780ebd147e9391020860d"), "name" : "replica set", "author" : "webinglin" }
CoamReSet:SECONDARY> exit
bye

至此,整个验证过程说明了我们集群部署是成功的.数据能够正常同步了.
那么接下来我们还要验证另一种情况,Primary异常终止之后（43.241.222.110）,另外两个Secondary节点会不会自动选举出新的Primary节点呢？
这个实验我们这样处理: 将 43.241.222.110 机器的mongod服务停止掉,然后再来连接 42.96.194.60 或者 45.63.50.67 任意一台机器,通过 rs.status() 查看集群状态.

在Primary节点（43.241.222.110）通过 ps -e | grep mongod 查看mongod服务是否开启,然后通过 killall mongod 或者 kill -15 <进程号> 来杀死mongod进程

root@ubuntu:~# ps -e | grep mongod
 3279 pts/0    00:00:19 mongod
root@ubuntu:~# killall mongod

登陆从节点 42.96.194.60 ,查看mongo服务器状态

root@ubuntu:~# mongo --host 42.96.194.60
MongoDB shell version: 3.0.3
connecting to: 42.96.194.60:27017/test
Server has startup warnings:
2015-06-09T17:03:11.647-0700 I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2015-06-09T17:03:11.647-0700 I CONTROL  [initandlisten]
2015-06-09T17:03:11.647-0700 I CONTROL  [initandlisten]
2015-06-09T17:03:11.648-0700 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2015-06-09T17:03:11.648-0700 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2015-06-09T17:03:11.648-0700 I CONTROL  [initandlisten]
CoamReSet:SECONDARY> rs.status()
{
    "set" : "CoamReSet",
    "date" : ISODate("2015-10-01T10:09:57.981Z"),
    "myState" : 1,
    "members" : [
        {
            "_id" : 0,
            "name" : "43.241.222.110:27017",
            "health" : 0,
            "state" : 8,
            "stateStr" : "(not reachable/healthy)",
            "uptime" : 0,
            "optime" : Timestamp(0, 0),
            "optimeDate" : ISODate("1970-01-01T00:00:00Z"),
            "lastHeartbeat" : ISODate("2015-10-01T10:09:56.226Z"),
            "lastHeartbeatRecv" : ISODate("2015-10-01T10:07:54.850Z"),
            "pingMs" : 18,
            "lastHeartbeatMessage" : "Failed attempt to connect to 43.241.222.110:27017; couldn't connect to server 43.241.222.110:27017 (43.241.222.110), connection attempt failed",            "configVersion" : -1
        },
        {
            "_id" : 1,
            "name" : "42.96.194.60:27017",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 1577,
            "optime" : Timestamp(1443693679, 1),
            "optimeDate" : ISODate("2015-10-01T10:01:19Z"),
            "electionTime" : Timestamp(1443694079, 1),
            "electionDate" : ISODate("2015-10-01T10:07:59Z"),
            "configVersion" : 1,
            "self" : true
        },
        {
            "_id" : 2,
            "name" : "45.63.50.67:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 1481,
            "optime" : Timestamp(1443693679, 1),
            "optimeDate" : ISODate("2015-10-01T10:01:19Z"),
            "lastHeartbeat" : ISODate("2015-10-01T10:09:56.891Z"),
            "lastHeartbeatRecv" : ISODate("2015-10-01T10:09:57.259Z"),
            "pingMs" : 440,
            "configVersion" : 1
        }
    ],
    "ok" : 1
}
CoamReSet:SECONDARY> exit
bye

通过上面这段代码的观察,我们发现,当把原来的Primary节点停止掉后（43.241.222.110停止）, 那么整个mongodb的副本集群会重新选举出新的Primary节点（ 42.96.194.60 机器）

为了验证一下新选举的Primary是否正常,我们再次验证一把数据的同步情况,先连接到 42.96.194.60 主节点,将原来的数据删掉,再到 45.63.50.67 SECONDARY 进行验证,数据是否也被删除

连接到 42.96.194.60 主节点,将原来的数据删掉

root@ubuntu:~# mongo --host 42.96.194.60
CoamReSet:PRIMARY> use test
switched to db test
CoamReSet:PRIMARY> show collections
guids
CoamReSet:PRIMARY> db.guids.find()
{ "_id" : ObjectId("560d03099548a3e5bb8b03bf"), "name" : "replica set", "author" : "webinglin" }
{ "_id" : ObjectId("560d046f9548a3e5bb8b03c0"), "name" : "zhang", "author" : "yafei..." }
CoamReSet:PRIMARY> db.guids.remove({name:"zhang"})
WriteResult({ "nRemoved" : 1 })
CoamReSet:PRIMARY> db.guids.find()
{ "_id" : ObjectId("560d03099548a3e5bb8b03bf"), "name" : "replica set", "author" : "webinglin" }
CoamReSet:PRIMARY> exit
bye

再到 45.63.50.67 SECONDARY 进行验证,数据是否也被删除

root@ubuntu:~# mongo --host 45.63.50.67
CoamReSet:SECONDARY> rs.slaveOk()
CoamReSet:SECONDARY> db.guids.find()
{ "_id" : ObjectId("557780ebd147e9391020860d"), "name" : "replica set", "author" : "webinglin" }
CoamReSet:SECONDARY> exit
bye

实践后发现,先选举的Primary节点也正常工作.我们的整个Mongodb副本集群测试完成.

动态添加节点,删除节点.

在开始这个实验之前,先把 43.241.222.110 的机器重新启动,然后用mongo客户端连到 43.241.222.110 进行验证数据是否也同步了.
登录 43.241.222.110 之后,我们发现数据也同步了,然后43.241.222.110节点变成了 Secondary 节点了.

root@ubuntu:~# mongo
CoamReSet:SECONDARY> rs.slaveOk()
CoamReSet:SECONDARY> show dbs
local   0.000GB
syData  0.000GB
test    0.000GB
CoamReSet:SECONDARY> use test
switched to db test
CoamReSet:SECONDARY> show collections
guids
CoamReSet:SECONDARY> db.guids.find()
{ "_id" : ObjectId("560d03099548a3e5bb8b03bf"), "name" : "replica set", "author" : "webinglin" }
CoamReSet:SECONDARY> rs.status()
{
    "set" : "CoamReSet",
    "date" : ISODate("2015-10-01T10:21:53.366Z"),
    "myState" : 2,
    "syncingTo" : "42.96.194.60:27017",
    "members" : [
        {
            "_id" : 0,
            "name" : "43.241.222.110:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 68,
            "optime" : Timestamp(1443694583, 1),
            "optimeDate" : ISODate("2015-10-01T10:16:23Z"),
            "syncingTo" : "42.96.194.60:27017",
            "configVersion" : 1,
            "self" : true
        },
        {
            "_id" : 1,
            "name" : "42.96.194.60:27017",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 66,
            "optime" : Timestamp(1443694583, 1),
            "optimeDate" : ISODate("2015-10-01T10:16:23Z"),
            "lastHeartbeat" : ISODate("2015-10-01T10:21:53.026Z"),
            "lastHeartbeatRecv" : ISODate("2015-10-01T10:21:52.588Z"),
            "pingMs" : 16,
            "electionTime" : Timestamp(1443694079, 1),
            "electionDate" : ISODate("2015-10-01T10:07:59Z"),
            "configVersion" : 1
        },
        {
            "_id" : 2,
            "name" : "45.63.50.67:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 66,
            "optime" : Timestamp(1443694583, 1),
            "optimeDate" : ISODate("2015-10-01T10:16:23Z"),
            "lastHeartbeat" : ISODate("2015-10-01T10:21:51.818Z"),
            "lastHeartbeatRecv" : ISODate("2015-10-01T10:21:53.006Z"),
            "pingMs" : 311,
            "syncingTo" : "42.96.194.60:27017",
            "configVersion" : 1
        }
    ],
    "ok" : 1
}
CoamReSet:SECONDARY> exit
bye

登录到 42.96.194.60 Primary 节点,通过 rs.remove() 方法来删除副本集中的某一个节点,这里我们还是将 43.241.222.110 删除.删除之后我们还往 42.96.194.60 主节点中加入数据.

CoamReSet:PRIMARY> rs.remove("43.241.222.110:27017")
{ "ok" : 1 }
CoamReSet:PRIMARY> rs.status()
{
    "set" : "CoamReSet",
    "date" : ISODate("2015-10-01T10:24:35.061Z"),
    "myState" : 1,
    "members" : [
        {
            "_id" : 1,
            "name" : "42.96.194.60:27017",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 2455,
            "optime" : Timestamp(1443695065, 1),
            "optimeDate" : ISODate("2015-10-01T10:24:25Z"),
            "electionTime" : Timestamp(1443694079, 1),
            "electionDate" : ISODate("2015-10-01T10:07:59Z"),
            "configVersion" : 2,
            "self" : true
        },
        {
            "_id" : 2,
            "name" : "45.63.50.67:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 2358,
            "optime" : Timestamp(1443695065, 1),
            "optimeDate" : ISODate("2015-10-01T10:24:25Z"),
            "lastHeartbeat" : ISODate("2015-10-01T10:24:33.256Z"),
            "lastHeartbeatRecv" : ISODate("2015-10-01T10:24:34.102Z"),
            "pingMs" : 334,
            "configVersion" : 2
        }
    ],
    "ok" : 1
}
CoamReSet:PRIMARY> db.guids.find()
{ "_id" : ObjectId("560d03099548a3e5bb8b03bf"), "name" : "replica set", "author" : "webinglin" }
CoamReSet:PRIMARY> db.guids.insert({"name":"remove one node dync"})
WriteResult({ "nInserted" : 1 })
CoamReSet:PRIMARY> db.guids.find()
{ "_id" : ObjectId("560d03099548a3e5bb8b03bf"), "name" : "replica set", "author" : "webinglin" }
{ "_id" : ObjectId("560d0a1d7d9deef6a0890b1f"), "name" : "remove one node dync" }
CoamReSet:PRIMARY> exit
bye

删除 43.241.222.110 节点后,我们往 Primary 节点中加入了新的数据,然后先不要将 43.241.222.110 的 mongod 服务停掉,我们通过mongo连接到 43.241.222.110 的mongod服务来查看数据

root@ubuntu:~# mongo --host 43.241.222.110
> db.guids.find()
{ "_id" : ObjectId("560d03099548a3e5bb8b03bf"), "name" : "replica set", "author" : "webinglin" }
> exit
bye

实验结果可以知道,我们在 45.63.50.67 新加入的数据 {name:”remove one node dync”} 并没有同步到43.241.222.110（已从副本集中删除）.

为了让实验结果更加确切,我们查看 43.241.222.110 是否有同步了数据:

root@ubuntu:~# mongo –host 45.63.50.67
CoamReSet:SECONDARY> db.guids.find()
{ “_id” : ObjectId(“557780ebd147e9391020860d”), “name” : “replica set”, “author” : “webinglin” }
{ “_id” : ObjectId(“557785bcbb56172c8e069341”), “name” : “remove one node dync” }
CoamReSet:SECONDARY> exit
bye

实验数据可以看到, 45.63.50.67 同步了在 42.96.194.60 主节点中新增的文档 {“name”:”remove one node dync”},这样就证明了动态删除副本集中的某一个节点的实验成功了.那怎么动态添加节点到副本集中呢？

原理是一样的,但是调用的方法变成了 rs.add(“43.241.222.110:27017”)

CoamReSet:PRIMARY> rs.add("43.241.222.110:27017");
{ "ok" : 1 }
CoamReSet:PRIMARY> rs.status()
{
    "set" : "CoamReSet",
    "date" : ISODate("2015-10-01T10:32:45.284Z"),
    "myState" : 1,
    "members" : [
        {
            "_id" : 1,
            "name" : "42.96.194.60:27017",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 2945,
            "optime" : Timestamp(1443695560, 1),
            "optimeDate" : ISODate("2015-10-01T10:32:40Z"),
            "electionTime" : Timestamp(1443694079, 1),
            "electionDate" : ISODate("2015-10-01T10:07:59Z"),
            "configVersion" : 3,
            "self" : true
        },
        {
            "_id" : 2,
            "name" : "45.63.50.67:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 2849,
            "optime" : Timestamp(1443695560, 1),
            "optimeDate" : ISODate("2015-10-01T10:32:40Z"),
            "lastHeartbeat" : ISODate("2015-10-01T10:32:43.660Z"),
            "lastHeartbeatRecv" : ISODate("2015-10-01T10:32:44.079Z"),
            "pingMs" : 452,
            "syncingTo" : "42.96.194.60:27017",
            "configVersion" : 2
        },
        {
            "_id" : 3,
            "name" : "43.241.222.110:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 2,
            "optime" : Timestamp(1443695560, 1),
            "optimeDate" : ISODate("2015-10-01T10:32:40Z"),
            "lastHeartbeat" : ISODate("2015-10-01T10:32:44.739Z"),
            "lastHeartbeatRecv" : ISODate("2015-10-01T10:32:43.300Z"),
            "pingMs" : 16,
            "syncingTo" : "42.96.194.60:27017",
            "configVersion" : 3
        }
    ],
    "ok" : 1
}
CoamReSet:PRIMARY> exit
bye

在rs.status()返回的结果中可以看到,43.241.222.110 节点已经成功加入副本集中了.加入之后,理论上应该会把在 43.241.222.110 主节点加入的数据同步过来,刚才删除之后是不会同步的.那这时候重新加入副本集,应该是要同步的.下面是实验结果:

root@ubuntu:~# mongo
CoamReSet:SECONDARY> db.guids.find()
{ "_id" : ObjectId("560d03099548a3e5bb8b03bf"), "name" : "replica set", "author" : "webinglin" }
{ "_id" : ObjectId("560d0a1d7d9deef6a0890b1f"), "name" : "remove one node dync" }
CoamReSet:SECONDARY> exit
bye

实验结果显示,动态添加操作也正常.动态的将 43.241.222.110 节点加入到副本集中能够保证数据同步成功.

注意

在调用 rs.add(“host:ip”) 或者 rs.remove(“host:ip”) 的时候,必须要在 Primary 节点中进行.

add方法可以加入一个document对象,这样就可以在指定具体的Secondary节点的更多的设置项了,比如指定为priority: 0 或 priority: 0,hidden: true 或 priority:0,hidden:true,arbiterOnly:true

{
  _id: <int>,
  host: <string>,
  arbiterOnly: <boolean>,
  buildIndexes: <boolean>,
  hidden: <boolean>,
  priority: <number>,
  tags: <document>,
  slaveDelay: <int>,
  votes: <number>
}

怎么对副本集进行权限验证,参考主从复制的安全部分,也是通过openssl来生成keyfile,然后再启动mongod的时候指定keyFile来设置安全的

也可以在三个主机的复制集添加以下配置

replication:
##oplog大小
 oplogSizeMB: 20
##复制集名称
 replSetName: CoamReSet

复制集优先级问题

默认设定节点 43.241.222.110 为Primary主节点,由于初始配置中没有设定,于是在主节点服务器重启后 43.241.222.110 自动切换成从节点,而 42.96.194.60 切换成了主节点导致应用程序连接错误
于是在当前主节点 43.241.222.110 通过命令行手动切换主节点到 43.241.222.110

CoamReSet:PRIMARY> rs.status()
{
        "set" : "CoamReSet",
        "date" : ISODate("2015-10-09T11:28:28.585Z"),
        "myState" : 1,
        "members" : [
                {
                        "_id" : 1,
                        "name" : "42.96.194.60:27017",
                        "health" : 1,
                        "state" : 1,
                        "stateStr" : "PRIMARY",
                        "uptime" : 614570,
                        "optime" : Timestamp(1444378212, 1),
                        "optimeDate" : ISODate("2015-10-09T08:10:12Z"),
                        "electionTime" : Timestamp(1444378334, 1),
                        "electionDate" : ISODate("2015-10-09T08:12:14Z"),
                        "configVersion" : 3,
                        "self" : true
                },
                {
                        "_id" : 2,
                        "name" : "45.63.50.67:27017",
                        "health" : 0,
                        "state" : 8,
                        "stateStr" : "(not reachable/healthy)",
                        "uptime" : 0,
                        "optime" : Timestamp(0, 0),
                        "optimeDate" : ISODate("1970-01-01T00:00:00Z"),
                        "lastHeartbeat" : ISODate("2015-10-09T11:28:27.754Z"),
                        "lastHeartbeatRecv" : ISODate("2015-10-06T08:52:51.239Z"),
                        "pingMs" : 406,
                        "lastHeartbeatMessage" : "Failed attempt to connect to 45.63.50.67:27017; couldn't connect to server 45.63.50.67:27017 (45.63.50.67), connection attempt failed",
                        "configVersion" : -1
                },
                {
                        "_id" : 3,
                        "name" : "43.241.222.110:27017",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 90994,
                        "optime" : Timestamp(1444378212, 1),
                        "optimeDate" : ISODate("2015-10-09T08:10:12Z"),
                        "lastHeartbeat" : ISODate("2015-10-09T11:28:27.532Z"),
                        "lastHeartbeatRecv" : ISODate("2015-10-09T11:28:27.299Z"),
                        "pingMs" : 15,
                        "configVersion" : 3
                }
        ],
        "ok" : 1
}

CoamReSet:PRIMARY> config = rs.conf()
{
        "_id" : "CoamReSet",
        "version" : 3,
        "members" : [
                {
                        "_id" : 1,
                        "host" : "42.96.194.60:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 1,
                        "tags" : {

                        },
                        "slaveDelay" : 0,
                        "votes" : 1
                },
                {
                        "_id" : 2,
                        "host" : "45.63.50.67:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 1,
                        "tags" : {

                        },
                        "slaveDelay" : 0,
                        "votes" : 1
                },
                {
                        "_id" : 3,
                        "host" : "43.241.222.110:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 1,
                        "tags" : {

                        },
                        "slaveDelay" : 0,
                        "votes" : 1
                }
        ],
        "settings" : {
                "chainingAllowed" : true,
                "heartbeatTimeoutSecs" : 10,
                "getLastErrorModes" : {

                },
                "getLastErrorDefaults" : {
                        "w" : 1,
                        "wtimeout" : 0
                }
        }
}

设置第一个节点 42.96.194.60 优先级为1,第二个节点 45.63.50.67 优先级为0,第三个节点 43.241.222.110 优先级为2;

CoamReSet:PRIMARY> config.members[0].priority = 1
1
CoamReSet:PRIMARY> config.members[1].priority = 0
0
CoamReSet:PRIMARY> config.members[2].priority = 2
2
CoamReSet:PRIMARY> rs.reconfig(config)
{ "ok" : 1 }
CoamReSet:PRIMARY> rs.status()
{
        "set" : "CoamReSet",
        "date" : ISODate("2015-10-09T12:03:37.679Z"),
        "myState" : 2,
        "syncingTo" : "43.241.222.110:27017",
        "members" : [
                {
                        "_id" : 1,
                        "name" : "42.96.194.60:27017",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 616679,
                        "optime" : Timestamp(1444392119, 1),
                        "optimeDate" : ISODate("2015-10-09T12:01:59Z"),
                        "syncingTo" : "43.241.222.110:27017",
                        "configVersion" : 5,
                        "self" : true
                },
                {
                        "_id" : 2,
                        "name" : "45.63.50.67:27017",
                        "health" : 0,
                        "state" : 8,
                        "stateStr" : "(not reachable/healthy)",
                        "uptime" : 0,
                        "optime" : Timestamp(0, 0),
                        "optimeDate" : ISODate("1970-01-01T00:00:00Z"),
                        "lastHeartbeat" : ISODate("2015-10-09T12:03:35.875Z"),
                        "lastHeartbeatRecv" : ISODate("2015-10-06T08:52:51.239Z"),
                        "pingMs" : 406,
                        "lastHeartbeatMessage" : "Failed attempt to connect to 45.63.50.67:27017; couldn't connect to server 45.63.50.67:27017 (45.63.50.67), connection attempt failed",
                        "configVersion" : -1
                },
                {
                        "_id" : 3,
                        "name" : "43.241.222.110:27017",
                        "health" : 1,
                        "state" : 1,
                        "stateStr" : "PRIMARY",
                        "uptime" : 93103,
                        "optime" : Timestamp(1444392119, 1),
                        "optimeDate" : ISODate("2015-10-09T12:01:59Z"),
                        "lastHeartbeat" : ISODate("2015-10-09T12:03:35.817Z"),
                        "lastHeartbeatRecv" : ISODate("2015-10-09T12:03:36.764Z"),
                        "pingMs" : 17,
                        "electionTime" : Timestamp(1444390463, 1),
                        "electionDate" : ISODate("2015-10-09T11:34:23Z"),
                        "configVersion" : 5
                }
        ],
        "ok" : 1
}

可以看到 43.241.222.110 已经成功切换成主节点了
关闭主节点 43.241.222.110 后,发现两个从节点没有自动切换成主节点,相当于关闭了 MongoDB 复制集功能
MongoDB RS优先级设置
 http://docs.mongodb.org/manual/tutorial/force-member-to-be-primary/

2016-01-10

Title

MongoDB 管理笔记摘要

MongoDB 修改重命名字段名

通过命令行批量修改

修改一级字段名

CoamReSet:PRIMARY> db.TruckRoadsPath.update({},{$rename:{"Lng":"lng"}},{multi:true})
WriteResult({ "nMatched" : 2702582, "nUpserted" : 0, "nModified" : 2702582 })

修改二级字段名

CoamReSet:PRIMARY> db.TruckRoadsPath.update({},{$rename:{“PathInfo.Speed”:”PathInfo.speed”}},{multi:true})

出现以下错误,提示不能更新 PathInfo 为 null 的数据,提示更新失败,但检查数据发现已全部正确更新过来了

WriteResult({
        "nMatched" : 0,
        "nUpserted" : 0,
        "nModified" : 0,
        "writeError" : {
                "code" : 16837,
                "errmsg" : "cannot use the part (PathInfo of PathInfo.Speed) to traverse the element ({PathInfo: null})"
        }
})

正确的检查非 null 条件下的写法应该是:

CoamReSet:PRIMARY> db.TruckRoadsPath.update({"PathInfo":{$ne:null}},{$rename:{"PathInfo.State":"PathInfo.state"}},{multi:true})
WriteResult({ "nMatched" : 2702158, "nUpserted" : 0, "nModified" : 2702156 })

参考 How do you query this in Mongo? (is not null)

参考
如何在MongoDB 修改字段名称,重命名字段
 Mongo docs - $rename

2016-01-10

Title

GPS相关

gps纠偏数据库及gps纠偏算法PHP

2016-01-10

RebarNote

使用 Rebar 管理 erlang 项目

GitHub -

使用 Intellij idea15 利用 rebar 开发调试 ejabberd

默认 Erlang 的 ejabberd 根项目下已经有 rebar 文件了

1.Win下安装 otp.18 到 G:\Program Files\erl7.2.1 下
2.将 G:\Program Files\erl7.2.1 添加系统环境变量 PATH
3.Intellij idea 项目 ejabberd 中 SDK 添加 OTP18.**
4.win下使用 Cygwin 安装 rebar

$ git clone git://github.com/rebar/rebar.git
$ cd rebar
$ ./bootstrap
Recompile: src/getopt
...
Recompile: src/rebar_utils
==> rebar (compile)
Congratulations! You now have a self-contained script called "rebar" in
your current working directory. Place this script anywhere in your path
and you can use rebar to build OTP-compliant apps.

它将自动将 rebar 安装到 C:\Users\yafei\rebar 下

File->Other Setting->Default Setting->Erlang Extenal Tools 配置 PATH 为 C:\Users\yafei\rebar\rebar.cmd
File->Setting->Setting->In “Build, Execution, Deployment/Erlan Compiler”, 勾选 “Compile project with rebar”.

6.Menu -> Run -> Edit Configurations -> 添加按钮 -> Erlang Rebar ,具体配置为在 Command 一栏添加任务 delete-deps clean get-deps compile 并任意填写一个任务名称 coamerlangtask

7.在 Intellij idea 右上角可以点击运行开始打包

错误分析

rebar unable to get dependency from github

使用简单的 clean compile 命令会出现很多未找到依赖包 * ,因为编译 compile 前先要 get-deps 所以将 rebar 编译命令改为 delete-deps clean get-deps compile

参考 rebar unable to get dependency from github

参考列表
Rebar commands
Using Intellij IDEA to write and debug Erlang code
Intellij Idea 官网说明
 windows下使用IntelliJ IDEA的erlang编译环境搭建(含rebar工具)

2016-01-10

MnesiaNote

Erlang Mnesia Database

Erlang Mnesia Doc

最近学习erlang,在erlang中天然集成了一个分布式数据库名字叫mnesia,因为数据库天然就和erlang的元组,记录无缝结合,并且具有良好的分布式特性,能够自动地在几个erlang节点上实现数据复制,效果有点像zookeeper的节点集群,
而且mnesia还支持数据库事务特性,所以mnesia在erlang应用中使用得非常频繁.

要在本地创建一个mnesia数据库,并且要实现插入,查询功能需要实现以下这几步:
1.启动erlang节点:

#erl -mnesia dir '"d://tmp//mnesia"' -sname mynode
erl -mnesia dir '"C:\Users\yafei\DevWork\Erlang\dev\mnesia\data"' -name win@27.16.194.65 -setcookie 456789
sudo erl -mnesia dir '"/data/home/data/mnesia/"' -name ali@42.96.194.60 -setcookie 456789

注意路径双引号
以上这个 “/data/home/data/mnesia/“ 目录是存放mnesia数据库的schema数据的,当然这个目录也可以不指定,那么mnesia数据库启动之后将把数据库的schema中的数据放在内存中,如果下次节点重启之后,之前数据库中创建的表结构数据就消失了.
2.接下来就是在erl shell中本地初始化一个空的 mnesia 数据库

mnesia:create_schema([node()]).

从参数上是一个节点列表,所以其实需要的话,可以在参数列表上设置多个erlang节点,就能在多个erlang节点上同时创建mnesia数据库并构成 Mnesia 集群.
3.启动mnesia数据库
初始化完成了mnesia数据库schema之后,接下来就可以启动mneisa数据库了.

mnesia:start().

至此,一个空的mneisa已经创建启动成功了,我们可以调用mnesia:info(). 查看当前mnesia数据库的一些状态,结果如下:

(ali@localhost)2> mnesia:info().
===> System info in version "4.13.2", debug level = none <===
opt_disc. Directory "/data/home/data/mnesia" is used.
use fallback at restart = true
running db nodes   = []
stopped db nodes   = [ali@localhost]
ok
(ali@localhost)3> mnesia:start().
ok
(ali@localhost)4> mnesia:info().
---> Processes holding locks <---
---> Processes waiting for locks <---
---> Participant transactions <---
---> Coordinator transactions <---
---> Uncertain transactions <---
---> Active tables <---
schema         : with 1        records occupying 408      words of mem
===> System info in version "4.13.2", debug level = none <===
opt_disc. Directory "/data/home/data/mnesia" is used.
use fallback at restart = false
running db nodes   = [ali@localhost]
stopped db nodes   = []
master node tables = []
remote             = []
ram_copies         = []
disc_copies        = [schema]
disc_only_copies   = []
[{ali@localhost,disc_copies}] = [schema]
2 transactions committed, 0 aborted, 0 restarted, 0 logged to disc
0 held locks, 0 in queue; 0 local transactions, 0 remote
0 transactions waits for other nodes: []
ok

从 [{ali@localhost,disc_copies}] = [schema] 这行上来看当前数据库中只有一个数据库的schema表.

Mnesia 集群

分别在阿里云 ali 和本机 win 启动两个节点

sudo -mnesia dir '"/data/home/data/mnesia/"' -name ali@42.96.194.60 -setcookie 456789
erl -mnesia dir '"C:\Users\yafei\DevWork\Erlang\dev\mnesia\data"' -name win@27.16.194.65 -setcookie 456789

保证两个节点都启动,并且 mnesia 没有启用

mnesia:delete_schema(['win@27.16.194.65', 'ali@42.96.194.60']).
mnesia:create_schema(['win@27.16.194.65', 'ali@42.96.194.60']).

然后启动两个节点的 mnesia,查看运行详情

(win@27.16.194.65)9> mnesia:start().
(win@27.16.194.65)9> mnesia:info().
---> Processes holding locks <---
---> Processes waiting for locks <---
---> Participant transactions <---
---> Coordinator transactions <---
---> Uncertain transactions <---
---> Active tables <---
schema         : with 1        records occupying 414      words of mem
===> System info in version "4.13.2", debug level = none <===
opt_disc. Directory [99,58,47,85,115,101,114,115,47,121,97,102,101,105,47,68,
101,118,87,111,114,107,47,69,114,108,97,110,103,47,100,
101,118,47,109,110,101,115,105,97,47,85,115,101,114,115,
121,97,102,101,105,68,101,118,87,111,114,107,69,114,108,
97,110,103,127,101,118,109,110,101,115,105,97,127,97,116,
97] is used.
use fallback at restart = false
running db nodes   = ['ali@42.96.194.60','win@27.16.194.65']
stopped db nodes   = []
master node tables = []
remote             = []
ram_copies         = []
disc_copies        = [schema]
disc_only_copies   = []
[{'ali@42.96.194.60',disc_copies},{'win@27.16.194.65',disc_copies}] = [schema]
3 transactions committed, 0 aborted, 1 restarted, 2 logged to disc
0 held locks, 0 in queue; 0 local transactions, 0 remote
0 transactions waits for other nodes: []
ok

根据 running db nodes = [‘ali@42.96.194.60’,’win@27.16.194.65’] 可以看出两个节点已成功组成节点

在任何一个节点添加数据表

erlang mnesia 数据库实现SQL查询

Mnesia是一个分布式数据库管理系统,适合于电信和其它需要持续运行和具备软实时特性的Erlang应用,越来越受关注和使用,但是目前Mnesia资料却不多,很多都只有官方的用户指南.
下面的内容将着重说明 Mnesia 数据库如何实现SQL查询,实现select / insert / update / where / order by / join / limit / delete等SQL操作.

参见示例 sql.erl

注:使用qlc模块查询,需要在文件顶部声明”-include_lib(“stdlib/include/qlc.hrl”).”,否则编译时会产生”Warning: qlc:q/1 called, but “qlc.hrl” not included”的警告.

使用单独的脚本连接 ejabberd mnesia 数据库

Cookie = 'YOUR_EJABBERD_COOKIE'. % mine was found in /var/lib/ejabberd/.erlang.cookie
EjabberdNode = 'ejabberd@127.0.0.1'. % or whatever you set as EJABBERD_NODE
erlang:set_cookie(EjabberdNode, Cookie).
net_adm:ping(EjabberdNode).
rpc:call(EjabberdNode, mnesia, system_info, [tables]).

参考 How can I connect to ejabberd’s Mnesia database with a separate script?

mnesia表数据Id自增长

1.使用函数:

mnesia:dirty_update_counter(unique_id, mine_result, 1).

2.该函数参数示意,
unique_id 表名, mine_result 表名,每次自增N.
3.
1.创建如下结构的mnesia数据库表 -record(unique_id, {item, uid}),该表是为了存储 mine_result 表的最大的Id值;
2.每为 mine_result 表加入一条新记录时,需要得到新的id值:

mnesia:dirty_update_counter(unique_id,  mine_result , 1),

从unique_id表中取出最大的Id值加1,更新unique_id表的数据,返回最大Id值加1,
注意:请在建立unique_id表的时候,往里面插入数据;表名,初始值,{ mine_result ,0},
我做了一个实验如果unique_id表中没有数据的时候,并发向mine_result库中插入100条数据时,不稳定.
但是unique_id表中加入一个数据后,并发数提高到30000,还是很稳定.

参考
wudaijun’s blog - Erlang mnesia
创设Mnesia数据库
 Erlang的Mnesia——为高伸缩性应用准备的数据库管理系统
 [Erlang-0008][OTP] 高效指南 – 表和数据库(ets mnesia)
Erlang基础Mnesia 之应用场景
 erlang Mnesia - 尚待研究

mnesia数据库使用体验
 mnesia数据库优化

2016-01-10

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