Centos7 installs MongoDB4 (stand-alone version)

1. Environmental description

Environment components	Version
hundred	7.6.1810
MongoDB	4.0.26

2. Installation steps

2.1 Download MongoDB binary version

wget https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-rhel70-4.0.26.tgz

2.2 Unzip to opt

tar -zxvf mongodb-linux-x86_64-rhel70-4.0.26.tgz -C /opt

2.3 Renaming a folder

mv mongodb-linux-x86_64-rhel70-4.0.26/ mongodb4.0.26/

2.4 Add to environment variables

A). vim /etc/profile

 86 export MONGO_HOME=/opt/mongodb4.0.26
 87 export PATH=$PATH:$MONGO_HOME/bin

B). source /etc/profile

2.5 Create the runtime data directory

A). Create "data+log" directory

mkdir -p /data/mongodb40/{
    
    log,data}

B). Create a configuration file directory

mkdir -p /opt/mongodb4.0.26/config

### C). 创建配置文件
```bash
cd /opt/mongodb4.0.26/config/

vim mongo11111.conf

2.6 Start MongoDB

/opt/mongodb4.0.26/bin/mongod -f /opt/mongodb4.0.26/config/mongo11111.conf

2.7 Test whether the startup is successful

curl http://localhost:11111

2.8 Add boot auto-start

echo “/opt/mongodb4.0.26/bin/mongod -f /opt/mongodb4.0.26/config/mongo11111.conf” >> /etc/rc.local

3. Manage users

3.1 Log in to MongoDB for the first time

mongo --port 11111

3.2 Create admin user (root)

# 切换到admin库
use admin

# 创建管理员用户,设置其账户为(root/123456)
db.createUser({
    
     user: "root", pwd: "123456", roles: [{
    
    role: "root", db: "admin"}] })

# 验证是否成功(返回1,即为成功)
db.auth("root", "123456")

3.3 Login with admin user

mongo --port 11111 -uroot -p123456

MongoDB shell version v4.0.26
connecting to: mongodb://127.0.0.1:11111/?gssapiServiceName=mongodb
Implicit session: session {
    
     "id" : UUID("965b8e97-7d57-4beb-9b61-4f53a57d169e") }
MongoDB server version: 4.0.26
Server has startup warnings: 
2022-04-19T22:34:01.665+0800 I STORAGE  [initandlisten] 
2022-04-19T22:34:01.665+0800 I STORAGE  [initandlisten] ** WARNING: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine
2022-04-19T22:34:01.665+0800 I STORAGE  [initandlisten] **          See http://dochub.mongodb.org/core/prodnotes-filesystem
2022-04-19T22:34:02.212+0800 I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2022-04-19T22:34:02.212+0800 I CONTROL  [initandlisten] 
2022-04-19T22:34:02.212+0800 I CONTROL  [initandlisten] 
2022-04-19T22:34:02.212+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2022-04-19T22:34:02.212+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2022-04-19T22:34:02.212+0800 I CONTROL  [initandlisten] 
2022-04-19T22:34:02.212+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2022-04-19T22:34:02.212+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2022-04-19T22:34:02.212+0800 I CONTROL  [initandlisten] 
---
Enable MongoDB's free cloud-based monitoring service, which will then receive and display
metrics about your deployment (disk utilization, CPU, operation statistics, etc).

The monitoring data will be available on a MongoDB website with a unique URL accessible to you
and anyone you share the URL with. MongoDB may use this information to make product
improvements and to suggest MongoDB products and deployment options to you.

To enable free monitoring, run the following command: db.enableFreeMonitoring()
To permanently disable this reminder, run the following command: db.disableFreeMonitoring()
---

> 

3.4 Create "Database + User"

1). Use the database (create it if you don't have one)
use testDB

2). Create a database management user and authorize it.
Note: On which library is this operation performed, it indicates which library the user belongs to; when logging in, authentication is required on the library

# 创建用户(需要在切换的testDB上做认证)
db.createUser( {
    
    user: "testUser", pwd: "123456", roles: [{
    
    role: "dbOwner", db: "testDB"}]} )

Test login:
mongo --host 127.0.0.1 --port 11111 -u testUser -p 123456 --authenticationDatabase testDB

3. Create a normal user for the database and set up authorization

use testDB

db.createUser( {
    
    user: "commonUser", pwd: "123456", roles: [{
    
    role: "readWrite", db: "testDB"}]} )

Fourth, MongoDB basic commands

4.1 Built-in database

There are some built-in databases in MongoDB, and the newly created database name cannot have the same name as these databases.

Environment components	Version
admin	It belongs to the privilege database, if you add a user to this database, the user will inherit all privileges of the database
config	Configuration class information
local	Data in the database will not be replicated
test	Default database, used to do some testing work

4.2 Common Commands

1. login to mongo

# 用户名/密码/认证服务器
mongo --host 127.0.0.1 --port 11111 -u testUser -p 123456 --authenticationDatabase testDB

2. switch or use a database

# 如无则创建
use dbName

3. View database version

db.version()

4. View the current database name

db.getName()

5. View current database address

db.getMongo()

6. View current database status

db.stats()

{
    
    
	"db" : "testDB",
	"collections" : 0,
	"views" : 0,
	"objects" : 0,
	"avgObjSize" : 0,
	"dataSize" : 0,
	"storageSize" : 0,
	"numExtents" : 0,
	"indexes" : 0,
	"indexSize" : 0,
	"fileSize" : 0,
	"fsUsedSize" : 0,
	"fsTotalSize" : 0,
	"ok" : 1
}