* Remove old docker packages
This removes docker packages that are obsolete if docker-ce packages are to be installed, which fixes some package conflict issues that can occur during upgrades.
* Add support for setting obsoletes=0 when installing docker with yum
This allows overriding of apt repo endpoints when internet sources are not accessible. Additionally, switch to using the dockerproject.org gpg key url for apt instead of keyservers.net
* Adding yaml linter to ci check
* Minor linting fixes from yamllint
* Changing CI to install python pkgs from requirements.txt
- adding in a secondary requirements.txt for tests
- moving yamllint to tests requirements
* Make yum repos used for installing docker rpms configurable
* TasksMax is only supported in systemd version >= 226
* Change to systemd file should restart docker
This will allow to use '-e docker_version=1.12' in ansible playbook
execution. It's also backward-compatible and will work with floating
docker_version format in custom yaml files.
Closes#702
On CoreOS where there is no package management, perform zero-trip
loops instead of throwing an exception for iterating over a member
of an undefined variable.
