Password-less SSH Login
On the source machine from which you want to initiate password-less ssh connections (admin), run ssh-keygen to generate a public and private key pair. The following is an example session showing the creation of a personal private/public key pair.
[chris@admin ~]$ ssh-keygen -t rsa Generating public/private rsa key pair. Enter file in which to save the key (/home/chris/.ssh/id_rsa): Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/chris/.ssh/id_rsa. Your public key has been saved in /home/chris/.ssh/id_rsa.pub. The key fingerprint is: f6:61:a8:27:35:cf:4c:6d:13:22:70:cf:4c:c8:a0:23 chris@admin
ssh-keygen -t rsa initiated the creation of the key pair. No passphrase was entered (Enter key was pressed instead). The private key was saved in
.ssh/id_rsa. This file is read-only and should be kept private, no one else must see the content of this file, as it is used to decrypt all correspondence encrypted with the public key
The public key is save in
.ssh/id_rsa.pub. The contents of this file might look something like the following.
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEArkwv9X8eTVK4F7pMlSt45pWoiakFkZMw G9BjydOJPGH0RFNAy1QqIWBGWv7vS5K2tr+EEO+F8WL2Y/jK4ZkUoQgoi+n7DWQVOHsR ijcS3LvtO+50Np4yjXYWJKh29JL6GHcp8o7+YKEyVUMB2CSDOP99eF9g5Q0d+1U2WVdB WQM= chris@admin
It is one line in length. To enable password-less ssh logins to a set of machines, slave01, slave02, and slave03, copy the
.ssh/id_rsa.pub file to all three machines and then concatenate it to the file
~/.ssh/authorized_keys on each of the three machines. Make sure the file access permissions are correct on all the ssh files and directories. On the source machine (admin):
$ chmod 755 ~ $ chmod 700 ~/.ssh $ chmod 600 ~/.ssh/id_rsa
On the target machines (slave01, slave02, slave03):
$ chmod 755 ~ $ chmod 700 ~/.ssh $ chmod 400 ~/.ssh/authorized_keys