【Mongo】安装并配置副本集

安装Mongo并配置副本集

最近的一个小项目需要用到mongo，所以开始学习下mongo。本打算开三台虚机严格按照生产来配置，然后发现有点带不动，所以决定在一台上通过三个端口来模拟。

获取安装包

curl -O http://downloads.mongodb.org/linux/mongodb-linux-x86_64-amazon-v3.4-latest.tgz?_ga=2.171604200.975923994.1528767763-1028766958.1526889489

其中，目录格式如下：

[root@localhost data]# tree /data/backup /data/lost+found /data/replset
/data/backup
/data/lost+found
/data/replset
├── file
├── logs
└── mongodb
    └── mongodb-linux-x86_64-amazon-v3.-latest.tgz

解压并创建软连接

tar -zxvf mongodb-linux-x86_64-amazon-v3.-latest.tgz ln -s mongodb-linux-x86_64-amazon-v3.-latest.tgz mongodb

创建用户及目录

groupadd  mongo
useradd   mongo -g mongo

mongo用户下执行：


mkdir  -p /data/replset/mongodb
mkdir  -p /data/replset/file/
mkdir  -p /data/replset/logs

操作系统层参数及配置

vi /etc/selinux/config

#SELINUX=enforcing#注释掉

#SELINUXTYPE=targeted#注释掉

SELINUX=disabled#增加

setenforce #使配置立即生效

关闭透明大页

vi /etc/rc.local
if test -f/sys/kernel/mm/transparent_hugepage/enabled; then
       echo never >/sys/kernel/mm/transparent_hugepage/enabled
fi
if test -f/sys/kernel/mm/transparent_hugepage/defrag; then
       echo never >/sys/kernel/mm/transparent_hugepage/defrag
fi

编辑mongodb.conf文件（此文件就相当于MySQL中的my.cnf文件，将其放在/data/replset/mongodb下）

[root@localhost ~]# cat /data/replset/mongodb/mongodb/mongodb.conf
wiredTigerCacheSizeGB =
syncdelay =
wiredTigerCollectionBlockCompressor = snappy
port=
dbpath=/data/replset/file/
logpath=/data/replset/logs/log1
logappend=true
oplogSize=
replSet=rs01
fork = true
auth= false
directoryperdb=true
pidfilepath =/data/replset/mongodb/mongod_rep1.pid
maxConns =
profile=
slowms=
journal=true

配置环境变量

echo "export PATH=/data/replset/mongodb/mongodb/bin:$PATH" >> /etc/profile

初始化数据库

mongod -f /data/replset/mongodb/mongodb.conf

登陆mongo（至此，但实例mongo便安装成功，非常简单，下面开始配置副本集）

​

为了配置副本集，至少再需要两个mongo实例，所以只需要再创建两份数据目录就可以了。 

并创建两份配置文件，在上面的配置文件中修改相应的目录以及优先级即可，然后初始化另两个实例

配置副本集（在任意一个实例上配置即可）

    cfg = {    _id: "rs01",
    members: [{
        _id: ,
        host: "192.168.179.134:27017",
        priority:
    }, {
        _id: ,
        host: "192.168.179.134:27018",
        priority:
    }, {
        _id: ,
        host: "192.168.179.134:27019",
        arbiterOnly: true
    }]
};

初始化配置

rs.initiate(cfg)

添加仲裁节点

rs.addArb("192.168.179.134:27019");

查看集群配置情况

rs01:PRIMARY> rs.status()
{
    "set" : "rs01",
    "date" : ISODate("2018-06-15T02:40:45.772Z"),
    "myState" : ,
    "term" : NumberLong(),
    "syncingTo" : "",
    "syncSourceHost" : "",
    "syncSourceId" : -,
    "heartbeatIntervalMillis" : NumberLong(),
    "optimes" : {
        "lastCommittedOpTime" : {
            "ts" : Timestamp(, ),
            "t" : NumberLong()
        },
        "appliedOpTime" : {
            "ts" : Timestamp(, ),
            "t" : NumberLong()
        },
        "durableOpTime" : {
            "ts" : Timestamp(, ),
            "t" : NumberLong()
        }
    },
    "members" : [
        {
            "_id" : ,
            "name" : "192.168.179.134:27017",
            "health" : ,
            "state" : ,
            "stateStr" : "PRIMARY",
            "uptime" : ,
            "optime" : {
                "ts" : Timestamp(, ),
                "t" : NumberLong()
            },
            "optimeDate" : ISODate("2018-06-15T02:40:37Z"),
            "syncingTo" : "",
            "syncSourceHost" : "",
            "syncSourceId" : -,
            "infoMessage" : "could not find member to sync from",
            "electionTime" : Timestamp(, ),
            "electionDate" : ISODate("2018-06-15T02:40:35Z"),
            "configVersion" : ,
            "self" : true,
            "lastHeartbeatMessage" : ""
        },
        {
            "_id" : ,
            "name" : "192.168.179.134:27018",
            "health" : ,
            "state" : ,
            "stateStr" : "SECONDARY",
            "uptime" : ,
            "optime" : {
                "ts" : Timestamp(, ),
                "t" : NumberLong()
            },
            "optimeDurable" : {
                "ts" : Timestamp(, ),
                "t" : NumberLong()
            },
            "optimeDate" : ISODate("2018-06-15T02:40:37Z"),
            "optimeDurableDate" : ISODate("2018-06-15T02:40:37Z"),
            "lastHeartbeat" : ISODate("2018-06-15T02:40:43.965Z"),
            "lastHeartbeatRecv" : ISODate("2018-06-15T02:40:41.900Z"),
            "pingMs" : NumberLong(),
            "lastHeartbeatMessage" : "",
            "syncingTo" : "192.168.179.134:27017",
            "syncSourceHost" : "192.168.179.134:27017",
            "syncSourceId" : ,
            "infoMessage" : "",
            "configVersion" :
        },
        {
            "_id" : ,
            "name" : "192.168.179.134:27019",
            "health" : ,
            "state" : ,
            "stateStr" : "ARBITER",
            "uptime" : ,
            "lastHeartbeat" : ISODate("2018-06-15T02:40:43.966Z"),
            "lastHeartbeatRecv" : ISODate("2018-06-15T02:40:41.806Z"),
            "pingMs" : NumberLong(),
            "lastHeartbeatMessage" : "",
            "syncingTo" : "",
            "syncSourceHost" : "",
            "syncSourceId" : -,
            "infoMessage" : "",
            "configVersion" :
        }
    ],
    "ok" :
}

Tip：

1、第一次启动时，发现mongo无法启动，报错当时没有记录（印象中报错是和副本集有关，因为当时配置文件中写了 “replSet=rs01” 申明了副本集），于是把该参数去掉后发现能正常启动。

然后新建另一个实例（想复现此问题），也写了 “replSet=rs01” ，启动时却没有报错，能够正常启动（很奇怪）。于是又做了两个实例，发现还是能正常启动。至此，怀疑是和版本有关系，或者是偶发性的bug，后面有时间会继续测试下这个问题。