在搭建 MongoDB 集群的基础上，详情见这里，追加认证
生成密钥
在集群的任意一台服务器上执行下述命令，生成密钥：
cd /usr/local/mongodb/
mkdir key
openssl rand -base64 756 > /usr/local/mongodb/key/key.file
chmod 400 /usr/local/mongodb/key/key.file
将密钥复制到其他两台服务器
创建用户
在集群的任意一台服务器上执行下述命令，创建用户：
cd /usr/local/mongodb/bin/
./mongo --port 27017
use admin
db.createUser({user: "lin",pwd: "123456",roles: [ { role: "root", db: "admin" } ]})
db.auth("lin","123456")
重启服务
三台服务器均执行
执行下述命令，杀死所有 MongoDB 进程：
ps -ef|grep mongo|grep -v grep|awk '{print $2}'|xargs kill -9
然后执行下述命令，重启服务：
nohup ./mongod -f /usr/local/mongodb/conf/config.conf --keyFile /usr/local/mongodb/key/key.file &
./mongod -f /usr/local/mongodb/conf/shard1.conf --keyFile /usr/local/mongodb/key/key.file
./mongod -f /usr/local/mongodb/conf/shard2.conf --keyFile /usr/local/mongodb/key/key.file
./mongod -f /usr/local/mongodb/conf/shard3.conf --keyFile /usr/local/mongodb/key/key.file
./mongos -f /usr/local/mongodb/conf/mongos.conf --keyFile /usr/local/mongodb/key/key.file
链接校验
List<ServerAddress> addressList = new ArrayList<ServerAddress>();
addressList.add(new ServerAddress("192.168.3.115", 27017));
addressList.add(new ServerAddress("192.168.3.116", 27017));
addressList.add(new ServerAddress("192.168.3.117", 27017));
List<MongoCredential> credentialList = new ArrayList<MongoCredential>();
MongoCredential credential = MongoCredential.createScramSha1Credential("lin", "admin", "123456".toCharArray());
credentialList.add(credential);
MongoClient mongoClient = new MongoClient(addressList, credentialList);
MongoDatabase mongoDatabase = mongoClient.getDatabase("mytest");
MongoCollection<Document> mongoCollection = mongoDatabase.getCollection("user");
long count = mongoCollection.count();
System.out.println(count);