参考：http://docs.mongodb.org/manual/tutorial/generate-key-file/
Generate a Key File
Overview
This section describes how to generate a key file to store authentication information. After generating a key file, specify the key file using the keyFile option when starting a mongod or mongos instance.
A key’s length must be between 6 and 1024 characters and may only contain characters in the base64 set. The key file must not have group or world permissions on UNIX systems. Key file permissions are not checked on Windows systems.
1、Create a key file.
Create the key file your deployment will use to authenticate servers to each other.
To generate pseudo-random data to use for a keyfile, issue the following openssl command:
openssl rand -base64 741 > mongodb-keyfile
chmod 600 mongodb-keyfile
chown mongod.mongod mongodb-keyfile
You may generate a key file using any method you choose. Always ensure that the password stored in the key file is both long and contains a high amount of entropy. Using openssl in this manner helps generate such a key.
2、Specify the key file when starting a MongoDB instance.
Specify the path to the key file with the keyFile option.
另外有需要云服务器可以了解下创新互联cdcxhl.cn，海内外云服务器15元起步，三天无理由+7*72小时售后在线，公司持有idc许可证，提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案，具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势，专为企业上云打造定制，能够满足用户丰富、多元化的应用场景需求。
