示例：mongodb://root:root@127.0.0.1:27017/bcc-livenet?authSource=admin
通过admin库进行登录认证，进而操作bcc-livenet库
错误提示：
2019-03-03T23:45:55.214-0800 I ACCESS [conn33] Successfully authenticated as principal root on admin
2019-03-03T23:45:55.216-0800 I ACCESS [conn32] Unauthorized: not authorized on bcc-livenet to execute command { createIndexes: "addresstemp", indexes: [ { name: "address_1", key: { address: 1 }, background: true } ], lsid: { id: UUID("82726e6c-b177-43d7-82b6-74e7a54f0bb7") }, $db: "bcc-livenet" }
2019-03-03T23:45:55.214-0800 I ACCESS [conn33] Successfully authenticated as principal root on admin该句说明admin库用户密码正确，且登录成功
后面提示没有登录授权可能是
此时的admin库用户没有操作其他数据库的权限
db.grantRolesToUser("root", [{role:"readWriteAnyDatabase", db:"admin"}])
为其添加授权即可