ezjail is a perfect tool for jails. What it does is actually saving you a lot of keystrokes. It is a very nice bash script.
When you create a new jail one of the task ezjail is copying everything from /usr/jails/newjail to the new jails directory. For a reason my /usr/jails/newjail was empty, ezjail finished the task, saying all went fine but when I wanted to start the jail I had the following error:
ezjail-admin start my_shiny_new_jail
cannot start jail my_shiny_new_jail, basejail: No such file or directory
I start looking around the internet, haven’t found a solution. Then I created a jail on another server when I noticed that so many files are copied into the new jail, “wait a minute, why isn’t this happening on server #1?” So I installed jails almost from scratch, this solved the issue.