Problem description:
Starting namenodes on [masternode]
Masternode: Permission denied (publickey, password).
Starting datanodes
Masternode: Permission denied (publickey, password).
Slavenode1: Permission denied (publickey, password).
Slavenode2: Permission denied (publickey, password).
Starting secondary namenodes [masternode]
Masternode: Permission denied (publickey, password).

SSH has already been set up,
The root password is set,
For PermitRootLogin PermitRootLogin yes no
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Solution:
The first kind of way to
Error 1:1, the client root password is not set
Methods: under the root passwd resetting,
Reason 2,/etc/SSH/sshd_config file without configuration
Methods: modified or added PermitRootLogin yes for PermitRootLogin no, after restart the service SSHD restart,
Note: all need to configure the host and client, otherwise is invalid,

2
The second way to
Input: # usermod - l - d/home/apple apple -m hadoop

- new login name, l - d user home directories, new -m home directory content will be moved to a new location (use) with 3-d last hadoop is the original user name

Usermod -l zhang - d/home/zhang

Groupmod -n zhang zhang