I have a few Ubuntu boxes that run various cron jobs daily. As far as I know, there is no postfix or sendmail installed. What's the easiest and/or best way to get cron to send me an email when one of its jobs fail with an error?
cron notifies root by default, this is local user mail delivery only.
If you want to send emails to email@example.com, then install postfix (defaut conf with listen on localhost only) and modifies /etc/aliases to forward emails to root to firstname.lastname@example.org. Then run
and you're all set
You need to configure MTA (postfix, sendmail or the debian standard: exim, etc.). It may be problematic though if you don't have public, static IP in business IP range as most other blocks are blacklisted because of spammers.