ctools archive breaks charms that use packages from ubuntu archies

[Curtis Hovey]

Juju adds the cloud-tools archive and because it has a higher priority than Ubuntu's archive. the ibv8-3.14 is specifically a higher version that Ubuntu's npm package can use. Any change that needs npm will fail to install because of unmet dependencies.

https://launchpad.net/~ubuntu-cloud-archive/+archive/cloud-tools-next

eg.
sudo apt-get install -y build-essential bzr libyaml-dev python-dev python-virtualenv subversion nodejs npm mongodb-clients;
Reading package lists... Done
Building dependency tree
Reading state information... Done
python-virtualenv is already the newest version.
build-essential is already the newest version.
bzr is already the newest version.
python-dev is already the newest version.
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 npm : Depends: nodejs-dev but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
make: *** [deploy_sysdeps] Error 100

WORKAROUND
The charm, or using debug-hooks can create a file /etc/apt/preferences.d/let-precise-work
Package: *
Pin: release o=Canonical
Pin-Priority: 400

[James Page (james-page)]

This is a better PIN:

Package: *
Pin: release n=precise-updates/cloud-tools
Pin-Priority: 400

The one I provided originally will also impact Ubuntu Cloud Archive pockets for OpenStack.