[root@nn1 hadoop-2.9.0]# ./sbin/start-dfs.sh
Starting namenodes on [nn1]
nn1: namenode running as process 2707. Stop it first.
nn1: datanode running as process 2859. Stop it first.
dn1: bash: line 0: cd: /home/user1/hadoop-2.9.0: No such file or directory
dn1: bash: /home/user1/hadoop-2.9.0/sbin/hadoop-daemon.sh: No such file or directory
dn2: bash: line 0: cd: /home/user1/hadoop-2.9.0: No such file or directory
dn2: bash: /home/user1/hadoop-2.9.0/sbin/hadoop-daemon.sh: No such file or directory
Starting secondary namenodes [0.0.0.0]
0.0.0.0: secondarynamenode running as process 3052. Stop it first.
[root@nn1 hadoop-2.9.0]#

供参考：
硕士学位：
主机名=nn1
用户名=user1
奴隶1：
主机名=dn1
用户名=slave1
奴隶2：
主机名=dn2
用户名=slave2