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

Generate a ssh key in your workstation.
Look at the Aliases section.
Connect via ssh to each of the PCs by using cob1, cob2, cob3.
Create on each PC in directory ~/.ssh/ a file called authorized_keys.
Copy the public part of your ssh key into the authorized_keys-file of each PC.
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.