mongo安装维护

该文档默认命名和配置：

1. 复制集名称为：ulocation
2. 三台mongo实例，192.168.50.222（primary，第一台），192.168.50.223（secondary，第二胎），192.168.50.223（arbiter，第三台）
3. mongo数据目录：/var/lib/mongo/，日志目录/var/log/mongodb/,备份目录：/app/mongo/backup,keyfile文件：/app/mongo/mongo.keyfile

mongo centos安装卸载

注： 如下操作是在ip、防火墙、selinux都配置好后进行的。

1.配置yum源

vim /etc/yum.repos.d/mongodb-enterprise.repo 

[mongodb-enterprise]
name=MongoDB Enterprise Repository
baseurl=https://repo.mongodb.com/yum/redhat/$releasever/mongodb-enterprise/4.0/$basearch/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-4.0.asc

2.yum安装

yum install -y mongodb-enterprise-4.0.6 mongodb-enterprise-server-4.0.6 mongodb-enterprise-shell-4.0.6 mongodb-enterprise-mongos-4.0.6 mongodb-enterprise-tools-4.0.6

3.防止yum update更新

vim /etc/yum.conf 
exclude=mongodb-enterprise,mongodb-enterprise-server,mongodb-enterprise-shell,mongodb-enterprise-mongos,mongodb-enterprise-tools

4.常用命令

sudo service mongod start
sudo chkconfig mongod on
sudo service mongod stop
sudo service mongod restart

5.mongo centos移除

sudo service mongod stop
sudo yum erase $(rpm -qa | grep mongodb-enterprise)

sudo rm -r /var/log/mongodb
sudo rm -r /var/lib/mongo

以上5部骤参考：https://docs.mongodb.com/manual/tutorial/install-mongodb-enterprise-on-red-hat/

6.Percona Server for MongoDB 4.0 安装

yum install https://repo.percona.com/yum/percona-release-latest.noarch.rpm

percona-release enable psmdb-40 release
yum install percona-server-mongodb

service mongod start
chkconfig mongod on
service mongod stop

mongo开启身份认证（复制集环境）

https://docs.mongodb.com/manual/tutorial/enable-authentication/

创建keyfile

mkdir -p /app/mongo
openssl rand -base64 756 > /app/mongo/mongo.keyfile
chmod 400 /app/mongo/mongo.keyfile
chown mongod:mongod /app/mongo/mongo.keyfile�

创建超级管理员

mongo
use admin

db.createUser(
  {
    user: "admin",
    pwd: "admin@13579*01",
    roles: [ { role: "userAdminAnyDatabase", db: "admin" }, { "role" : "clusterAdmin", "db" : "admin" }, "readWriteAnyDatabase","root" ]
  }
)

创建ulocation管理员

use ulocation
db.createUser(
  {
    user: "ulocation",
    pwd: "ulocation2019",
    roles: [ { role: "readWrite", db: "ulocation" }]
  }
)

若为复制集，需将keyfile拷贝到其他节点上。

关闭mongo实例，修改配置文件：

security:
  authorization: enabled
  keyFile: /app/mongo/mongo.keyfile�

使用创建的用户登录

mongo --port 27017 -u "admin" --authenticationDatabase "admin" -p

mongo --port 27017 -u "ulocation" --authenticationDatabase "ulocation" -p
--authenticationDatabase : 指定用户在哪个库中创建，若不指定，mongo使用连接串中的数据库。

Standalone mongo实例转为复制集

1.关闭第一台实例

mongo
use admin
db.shutdownServer()

2.第一台实例增加复制集启动配置项，并启动

vim /etc/mongod.conf

replication:
  replSetName: ulocation
  enableMajorityReadConcern: false   # PSA架构需关闭此项

service mongod start

3.第一台实例配置复制集信息

mongo
config = {
    "_id":"ulocation",
    "members":[
        {"_id":0,"host":"192.168.50.222:27017"},
    ]
}
rs.initiate(config)

该节点为primary节点

4.新增secondary mongo

在第二台mongo实例，操作1、2两部

在primary上执行：
rs.add( { host: "192.168.50.223:27017", priority: 0, votes: 0 } )
调用该命令后，会自动执行Initial Sync，进行数据同步

修改priority和vote（原因：When a newly added secondary has its votes and priority settings greater than zero, during its initial sync, the secondary still counts as a voting member even though it cannot serve reads nor become primary because its data is not yet consistent.）
var cfg = rs.conf();
cfg.members[1].priority = 1
cfg.members[1].votes = 1
rs.reconfig(cfg)

5.新增仲裁成员

在第三台mongo实例，操作1、2两部
在primary上执行：
rs.addArb("192.168.50.224:27017")

参考：https://docs.mongodb.com/manual/tutorial/convert-standalone-to-replica-set/

https://docs.mongodb.com/manual/tutorial/expand-replica-set/

https://docs.mongodb.com/manual/tutorial/add-replica-set-arbiter/

Initial Sync数据同步

两种方式：

方式一：在primary上执行：rs.add( { host: "192.168.50.223:27017", priority: 0, votes: 0 } )。注：前提是空的数据目录

方式二：拷贝primary上的数据文件，步骤如下：

1.停掉primary，拷贝数据文件
2.停掉secondary将拷贝的数据文件移到secondary的数据目录
3.rm -rf mongod.lock（不删除会报“Attempted to create a lock file on a read-only directory: /var/lib/mongo”）
chown -R mongod:mongod *
4.启动secondary上的mongo实例

Percona Server热备份

mkdir -p /app/mongo/backup
chown -R mongod:mongod /app/mongo/backup

> use admin
switched to db admin
> db.runCommand({createBackup: 1, backupDir: "/app/mongo/backup"})
{ "ok" : 1 }

mongo shell常用语句

库操作：

show dbs;
use test;
test.dropDatabase();

查询语句：

日期：ISODate("2012-12-19T06:01:17.171Z")
db.inventory.find( {} )
db.inventory.find( { status: "D" } )
db.inventory.find( { status: { $in: [ "A", "D" ] } } )
db.inventory.find( { status: "A", qty: { $lt: 30 } } )
db.inventory.find( { $or: [ { status: "A" }, { qty: { $lt: 30 } } ] } )

赋角色：

db.grantRolesToUser(
    "dayunAdmin",
    [
      { role: "root", db: "admin" }
    ]
)   

复制集

rs.conf()
rs.status()
db.printReplicationInfo()
rs.printSlaveReplicationInfo()

FAQ

• (PSA) architecture关闭enableMajorityReadConcern

  Read Concern "majority": https://docs.mongodb.com/manual/reference/read-concern-majority/#disable-read-concern-majority

• 主节点db.shutdownServer(),会出现失败

    ulocation:PRIMARY> db.shutdownServer()
    2019-04-17T12:34:12.606+0800 E QUERY    [js] Error: shutdownServer failed: {
        "operationTime" : Timestamp(1555475638, 1),
        "ok" : 0,
        "errmsg" : "No electable secondaries caught up as of 2019-04-17T12:34:12.604+0800Please use the replSetStepDown command with the argument {force: true} to force node to step down.",
        "code" : 262,
        "codeName" : "ExceededTimeLimit",
        "$clusterTime" : {
            "clusterTime" : Timestamp(1555475638, 1),
            "signature" : {
                "hash" : BinData(0,"dHvSJ4hy78YRfqf0hSAotb29wuo="),
                "keyId" : NumberLong("6680450114256896002")
            }
        }
    } :
  

  解决：先降级，db.adminCommand( { replSetStepDown: 120, secondaryCatchUpPeriodSecs: 15, force: true } )，然后，关闭。

• 先正常运行，修改配置后运行不成功，还原回去后还不能正常运行

  删除 /tmp/mongodb-27017.sock