Add prepare-docker-dind role

This change adds the prepare-docker-dind role intended to
be used in tests to install docker on test containers.
Contrary to the prepare-docker role it arranges for docker daemon to be launched inside
of the test containers instead of using/polluting a test host.
It is a prerequisite to the rke role molecule tests.

Change-Id: I6be270758b01f7e9c4fa09aebcc32930c0977ea3
Issue-ID: OOM-1778
Signed-off-by: Michal Zegan <m.zegan@samsung.com>
diff --git a/ansible/test/roles/prepare-docker-dind/tasks/main.yml b/ansible/test/roles/prepare-docker-dind/tasks/main.yml
new file mode 100644
index 0000000..3e109e8
--- /dev/null
+++ b/ansible/test/roles/prepare-docker-dind/tasks/main.yml
@@ -0,0 +1,23 @@
+---
+# Needed because host system has all mounts by default to shared, and
+# some things may depend on mounts being shared if we run docker inside
+# test env.
+- name: "Make all mounts shared"
+  command: "mount --make-rshared /"
+  args:
+    warn: false
+
+- name: "Enable docker repository"
+  yum_repository:
+    name: "Docker"
+    description: Docker-ce repository
+    enabled: yes
+    baseurl: "https://download.docker.com/linux/centos/7/$basearch/stable"
+    gpgcheck: yes
+    gpgkey: https://download.docker.com/linux/centos/gpg
+
+- name: "Install docker"
+  package:
+    name: "docker-ce-{{ docker_version }}"
+    state: present
+  notify: Restart docker