搭建hadoop伪分布节点时ssh的设置

目标：ssh localhost 无需键入密码

步骤 ：

前提：确认主机安装ssh  shhd  分别是 ssh客户端和server端

使用hadoop账户：

ssh-keygen -t dsa -P '' -f ~/.ssh/id_dsa 
cat ~/.ssh/id_dsa.pub >> ~/.ssh/authorized_keys

建立好这些文件后，无需修改sshd_config或ssh_config文件

ssh客户端默认会在passwd验证之前，在本地~/.ssh目录下寻找dsa、rsa等加密方式的密钥文件，看能否免除密码键入的验证步骤

做好上述配置后，ssh localhost 还是需要键入密码

ssh -vv localhost   显示debug信息如下：

debug2: we did not send a packet, disable method

debug1: Next authentication method: publickey

debug1: Trying private key: /home/hadoop/.ssh/identity

debug1: Trying private key: /home/hadoop/.ssh/id_rsa

debug1: Offering public key: /home/hadoop/.ssh/id_dsa

debug2: we sent a publickey packet, wait for reply

debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password

debug2: we did not send a packet, disable method

debug1: Next authentication method: password

hadoop@localhost's password:

由上面debug信息可知，ssh在尝试发送rsa或dsa的public key，但是并没有发送出去we did not send a packet, disable method

猜测是权限问题

将.ssh权限改为700（原来是777）

 authorized_keys 权限改为600 （原来是666）

如此之后

ssh localhost 

无需输入密码

配置成功