多台服务器配置免密登陆
假设三台服务器192.168.1.111（node1）、192.168.1.112(node2)、192.168.1.113(node3)
比如hadoop用户下
groupadd hadoop 新建hadoop用户组
useradd -g hadoop hadoop hadoop用户组下新建hadoop用户
passwd hadoop 修改hadoop用户的密码
hadoop用户的目录 /home/hadoop
切换到hadoop用户下
su hadoop
第一步：
每台服务器生成rsa公钥、私钥
ssh-keygen -t rsa
一路回车
id_rsa.pub即为公钥
[hadoop@node1 ~]$ ssh-keygen -t rsa Generating public/private rsa key pair. Enter file in which to save the key (/home/hadoop/.ssh/id_rsa): Created directory '/home/hadoop/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/hadoop/.ssh/id_rsa. Your public key has been saved in /home/hadoop/.ssh/id_rsa.pub. The key fingerprint is: c7:c7:c5:fb:a5:5c:59:d6:eb:99:98:7b:31:9c:26:ae hadoop@node1 The key's randomart image is: +--[ RSA 2048]----+ | | | . .| | o +| | . . . o+| | S o o oo+| | . . o+X+| | .o=++| | ... | | E... | +-----------------+ [hadoop@node1 ~]$
第二步：
将每台服务器产生的公钥copy到第一台服务器192.168.1.111
ssh-copy-id hadoop@192.168.1.111
此时查看/home/hadoop/.ssh/authorized_keys
[hadoop@node1 .ssh]$ cat authorized_keys ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDMbR4B1rI+PqDfe/LqIOZyqNIoniayeKHzOC6gxqUFOEZXU15j8+qiJhd6ptgxpuLtlzpdypTZ3PjEHDKMKiNv9BOteo6Il9Q2x7gUCd2
dvbTbj0Sq4sJNasPS3twIu0h7pDvC2LqicF12mMNOTITAcHQo0b7urgJCQgoi7NlNYFWuJ/LzxqXWERTbMmCSzakm4X2foha+mY3ec0HfthMzzcJyrlyzrhTcSB19Lhw2uXWJWJPwL7R5Aa
r0qIIqjK/+084xMcTqucn4t3KFN/S1xIab60/QP/tNzMYF+Za0qg5xGgcRs1DxQPCTPEMghrUEaMgLFvxlpQOFrJAg9kOD hadoop@node1 ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC2Jn2Ozcqb+YacQzL8wdajfePXOuldqKBNc6byFMNWHU2AASl6RUlVw2vwilQ4SA0vwFZ2SLCQCOkdd4cKiGSCz+muro8/gTY9BomLw09
3sd3rkyLDDLfZ1CzmLemhuAgQ1vyxNBHTizVWaDlD7gSUuICpkHlXOVPqO/SS56sO/bGcDVe5cvyTL1Fy5L/ZKcyxPhmaLI4DzTfpBBgnSOSB81RNhzoEwRM8kudjnka4WtHBORn9HtM4E8
bnT9tPiGrpmEeo297LoerF3FCgmpxABA8mKmeLM/gOc+xzQkL008VjCN9oBcj2b+LH+E82jhbyHEv72ljRk/8S9bdJF1Vr hadoop@node2 ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDmB34n685esgquASpY31d4eq9zNgUmOXzW2F4RT3jHO1gOQiePqb5Kc6FA99IHyx28zfPJ/uKV+wek4Dk03jnQCmQAuVm6m4lxEBMiq83
OguGeqdfWbSAgqHeuXhy6+JHJzOY6xdtTvKwRDS3AGM3ewl4/4ZxLJDP8zY+4YptdvqDLA7ZYnoxxh7f680fpvvVtF073xopAGmDAe1u4/XXZvBCCZQCWMQlPuyRbmFh/uNSj8+yaKysNGe
/uAQ5xd2cpS7HAok+xv4D+w8xgr2KcSm9fD1+kH5M6/mpi2aLuhJCxJfW2KpbY+c8y19ObzgDzpxsw0vp4AL2Jzw6XcVrF hadoop@node3
第三步：
将192.168.1.111上的authorized_keys拷贝到另外两台服务器
scp /home/hadoop/.ssh/authorized_keys hadoop@192.168.1.112:/home/hadoop/.ssh/
scp /home/hadoop/.ssh/authorized_keys hadoop@192.168.1.113:/home/hadoop/.ssh/
第四步：
验证
192.168.111上
ssh hadoop@192.168.1.112
免密登陆成功。