管理员账号未知,创建一个管理员账号,需要重启
systemctl stop mongod
systemctl start mongod
注释: 
security:
    authorization: enabled
mongo --host 10.2.210.2  --port 27017
use admin;
db.createUser({user:"root",pwd:"root.COM2020",roles:[{role:"root",db:"admin"}]})
开启: 
security:
    authorization: enabled
systemctl stop mongod
systemctl start mongod
验证是否成功:
mongo --host 10.2.210.2  --port 27017
use admin;
db.auth('root','root.COM2020');
授权:
use admin;
db.auth('root','root.COM2020');
db.grantRolesToUser('finance_user',[{role:'readWrite',db:'saas_cash_settlement'}]) 
db.grantRolesToUser('finance_user',[{role:'read',db:'saas_cash_settlement'}]) 
验证是否成功、创建数据库:
mongo --host 10.2.210.2  --port 27017
use admin;
db.auth('finance_user','A4HSJdnvteRt311');
use saas_cash_settlement;
db.mytestcol.insert({name:"liu2",age:82,address:"fujian222"});