sudo add-apt-repository cloud-archive:juno
Long Term Support
The Cloud Tools archive is only supported on Ubuntu 12.04.
Add the repository to your apt sources by doing the following:---
sudo add-apt-repository cloud-archive:tools
sudo apt-get update
Then, apt-get install the packages you need.
原文：http://www.cnblogs.com/ruiy/p/4188250.html