一、创建root用户

1.创建root用户

> db.createUser({user:"root",pwd:"123456",roles:["root"]})
Successfully added user: { "user" : "root", "roles" : [ "root" ] }

2.关闭服务器

[root@wugenqiang ~]# mongod -shutdown -dbpath=/usr/local/mongodb/data
killing process with pid: 115534

3.重新启动服务器

[root@wugenqiang ~]# mongod --auth --dbpath=/usr/local/mongodb/data --journal

4.使用root用户连接mongodb数据库

[root@wugenqiang ~]# mongo admin -u root -p 123456

或者直接输入mongo

但是这种形式要执行以下操作：

> use admin
switched to db admin
> db.auth("root","123456") 

> use admin
switched to db admin
> db.auth("root","123456")
1
> show tables
system.users
system.version

二、创建普通用户

案例实现：

1.使用root用户登录

[root@wugenqiang ~]# mongo admin -u root -p 123456

2.切换到tomdb

> use tomdb
switched to db tomdb

3.在tomdb中创建一个用户tom，即tom属于tomdb

> db.createUser(
... {
... user:"tom",
... pwd:"123456",
... roles:[{role:"readWrite",db:"tomdb"}]
... }
... )
Successfully added user: {
	"user" : "tom",
	"roles" : [
		{
			"role" : "readWrite",
			"db" : "tomdb"
		}
	]
}

4.使用root用户，给tom用户授权访问test库

> db.grantRolesToUser("tom",[{role:"readWrite",db:"test"}])
> use test
switched to db test
> db
test

5.检查是否授权访问成功

> show users
{
	"_id" : "tomdb.tom",
	"user" : "tom",
	"db" : "tomdb",
	"roles" : [
		{
			"role" : "readWrite",
			"db" : "test"
		},
		{
			"role" : "readWrite",
			"db" : "tomdb"
		}
	]
}