2018-05-06-use-ssh-without-password

In order to adjust the settings to all PCs on Jenny, you need at least four terminals open in your workstation.

Overview

1. Generate a ssh key in your workstation.

2. Look at the Aliases section.

3. Connect via ssh to each of the PCs by using cob1, cob2, cob3.

4. Create on each PC in directory ~/.ssh/ a file called authorized_keys.

5. Copy the public part of your ssh key into the authorized_keys-file of each PC.

6. Copy the public part of each PC (cob1, cob2 and cob3) to the other PCs.

1. Generate a ssh key in your workstation

$ ssh-keygen -t rsa

2. Look at the Aliases section

3. Connect via ssh to each of the PCs by using cob1, cob2, cob3

4. Create authorized_keys-files

Execute in each of the PCs the following code in order to create the authorized_keys-file at the right place.

$ touch ~/.ssh/authorized_keys

5. Copy the public part of your ssh key into authorized_keys-files of each PC

Being in the terminal of your workstation execute the following lines of code (Note: username needs to be replaced by your own username). After each line you will need to enter your individual password one last time.

$ scp ~/.ssh/id_rsa.pub username@cob3-1-pc1:~/.ssh/authorized_keys

$ scp ~/.ssh/id_rsa.pub username@cob3-1-pc2:~/.ssh/authorized_keys

$ scp ~/.ssh/id_rsa.pub username@cob3-1-pc3:~/.ssh/authorized_keys

6. Copy the public part of each PC (cob1, cob2 and cob3) to the other PCs.

From the workstation connect to PC1 by executing the alias cob1 and execute the following commands to copy the public part of the ssh-key of PC1 to PC2 and PC3:

$ ssh-copy-id username@cob3-1-pc2

$ ssh-copy-id username@cob3-1-pc3

Switch to PC2 using the alias cob2 and execute the equivalent commands there:

$ ssh-copy-id username@cob3-1-pc1

$ ssh-copy-id username@cob3-1-pc3

Switch to the last remaining PC using the alias cob3 and also here copy the public part of the ssh-key to the other PCs:

$ ssh-copy-id username@cob3-1-pc1

$ ssh-copy-id username@cob3-1-pc2

Once all the steps are done you should be able to switch between the PCs by just using cob1, cob2, cob3. The password is then not needed anymore.

See also

• Aliases