How to automate rsync without asking for password prompt

Question

I would like to automate the rsync task as a cron job. Since it needs the passphrase I am not able to do the cronjob. I need to specify the passphrase along with the rsync command or I will store the passphrase in a file and I will read from it. My command will look like this:

rsync -aPe "ssh -i ' . $server->{'ssh_key'} . '" ' . $server_lock_dir;

So where do I put the password ?

Answer 1

You don't need to do that - just need to set up a pair of ssh keys and put the public key in the remote system's .ssh directory.

Then you just do this:

rsync -a -e ssh /local/path/ server:/remote/path/

(Note that -e ssh has been the default for quite a few years now, so you can probably omit it, unless you're using a very old version.)

There's a "how to" guide on setting up the keys here.

Answer 2

If you want this to work from cron, you have several possibilities:

• setup password-less ssh keys - not very secure
• setup password-less ssh keys, but combine them with ssh ForceCommand in the authorized_keys file to limit the commands that can be run with that ssh key. See man sshd, google on "ssh ForceCommand"
• setup passworded ssh keys, but combine them with keychain to keep the key in memory between sessions. I've written a blog post on this: ssh, ssh-agent, keychain and cron notes

Answer 3

If you want to copy files remotely:

1. Make sure you have a public key on your local machine that can log into the remote machine.(in this case the my ssh-key is "/home/myaccount/.ssh/id_rsa"
2. Specify local folder you want to sync with the remote, in my case "/home/myaccount/mysourcefolder"
3. Specify the destination folder full path in the remote server, in my case remoteaccount@remoteserver:"/home/remoteaccount/mydestinationfolder/"

---

Note:

• --progress is to show progress for each file being copied
• -a to transfer recusively all files in the mysourcefolder
• -v for verbosity
• -z to compress data portions for small files

My command will look like below:

rsync -avz --progress -e "ssh -i /home/myaccount/.ssh/id_rsa" /home/myaccount/mysourcefolder remoteaccount@remoteserver:"/home/remoteaccount/mydestinationfolder/"