Linux – How to prevent rsync (using ssh as remote shell) from facing a password prompt

linuxrsyncssh

I would like to run rsync without the need to enter a password. I understand I can do this using ssh keys and once the right key has been copied over to the remote server rsync logs in fine without user interaction.

However when the key has been changed, has been removed, or, say in case of some automation, a server has been added to a list of servers to be rsync'ed, I would like rsync to not be prompted for a password.

Meaning, rsync should only attempt to use password-less login with ssh and if that doesn't work move on without having to deal with a password prompt and a possible lengthy timeout.

Best Answer

You can configure the SSH client to not attempt password authentication:

rsync -e 'ssh -o PasswordAuthentication=no' ...

There is also a BatchMode option which disables password authentication and decreases the timeout:

rsync -e 'ssh -o BatchMode=yes' ...

Related Solutions

SSH – Hangs Without Password Prompt, Works in Root or Other Accounts

The reason your ssh client hangs for your account but not for other accounts (root) is probably because there is something wrong with your ssh-agent. Either that the ssh-agent is not running or that its configuration is wrong in some way.

To have a confirmation of that, you can try the following:

unset SSH_AUTH_SOCK
ssh mylogin@myremoteserver.com

If you're then asked to input the pass phrase to your ssh_key it means you have an issue with your ssh-agent.

See also my post on this related question.

Ssh – How to automate SSH login with password

Don't use a password. Generate a passphrase-less SSH key and push it to your VM.

If you already have an SSH key, you can skip this step… Just hit Enter for the key and both passphrases:

$ ssh-keygen -t rsa -b 2048
Generating public/private rsa key pair.
Enter file in which to save the key (/home/username/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/username/.ssh/id_rsa.
Your public key has been saved in /home/username/.ssh/id_rsa.pub.

Copy your keys to the target server:

$ ssh-copy-id id@server
id@server's password:

Now try logging into the machine, with ssh 'id@server', and check-in:

.ssh/authorized_keys

Note: If you don't have .ssh dir and authorized_keys file, you need to create it first

to make sure we haven’t added extra keys that you weren’t expecting.

Finally, check to log in…

$ ssh id@server

id@server:~$

You may also want to look into using ssh-agent if you want to try keeping your keys protected with a passphrase.

Best Answer

Related Solutions

SSH – Hangs Without Password Prompt, Works in Root or Other Accounts

Ssh – How to automate SSH login with password

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