Recipe 17.8. Passwordless Logins for cron Jobs
17.8.1 Problem
You want to schedule some
backups or file transfers via SSH, using cron.
How do you tell cron to look to
keychain to handle authentication of remote
hosts?
17.8.2 Solution
Use the same source line in your cron scripts
that you used in your .bash_profile. This is a
simple script that uses rsync to back up a
user's home directory:
#!/bin/bash
source /home/saz/.keychain/$HOSTNAME-sh
rsync -a -e ssh --delete --force rsync.test.net::home/saz/ /backups/saz
Slap it in a cron job, and
you're fully automated until the next reboot.
17.8.3 Discussion
Again, using null-passphrase keys leaves your private
keys wide open to being misused by anyone who gains access to them.
Using keychain ensures that you can properly
protect your SSH keys with passphrases and still automate SSH
transfers.
17.8.4 See Also
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