container-common: support podman on Ubuntu

Currently we're only able to use podman on ubuntu if podman's
installation is done manually before the ceph-ansible execution
because the deb package is present in an external repository.
We already manage the docker-ce installation via an external
repository so we should be able to allow the podman installation
with the same mechanism too.

https://github.com/containers/libpod/blob/master/install.md#ubuntu

Resolves: #3947

Signed-off-by: Dimitri Savineau <dsavinea@redhat.com>

roles/ceph-container-engine/tasks/pre_requisites/debian_prerequisites.yml

@@ -3,6 +3,7 @@
   package:
     name: ['docker', 'docker-engine', 'docker.io', 'containerd', 'runc']
     state: absent
+  when: container_package_name == 'docker-ce'
 
 - name: allow apt to use a repository over https (debian)
   package:
@@ -16,7 +17,16 @@
     url: 'https://download.docker.com/linux/{{ ansible_distribution | lower }}/gpg'
   register: result
   until: result is succeeded
+  when: container_package_name == 'docker-ce'
 
 - name: add docker repository
   apt_repository:
     repo: "deb https://download.docker.com/linux/{{ ansible_distribution | lower}} {{ ansible_distribution_release }} stable"
+  when: container_package_name == 'docker-ce'
+
+- name: add podman ppa repository
+  apt_repository:
+    repo: "ppa:projectatomic/ppa"
+  when:
+    - container_package_name == 'podman'
+    - ansible_distribution == 'Ubuntu'

roles/ceph-container-engine/tasks/pre_requisites/prerequisites.yml

@@ -9,7 +9,6 @@
   include_tasks: debian_prerequisites.yml
   when:
     - ansible_os_family == 'Debian'
-    - container_package_name == 'docker-ce'
   tags: with_pkg
 
 # ensure extras enabled for docker