Adding support for devicemapper storage driver

defaults/main.yml

@@ -17,3 +17,20 @@ docker_apt_repository: "deb https://download.docker.com/linux/{{ ansible_distrib
 docker_yum_repo_url: https://download.docker.com/linux/centos/docker-{{ docker_edition }}.repo
 docker_yum_repo_enable_edge: 0
 docker_yum_repo_enable_test: 0
+
+# Conditonally control docker daemon restart
+docker_restart: false
+
+# Used only for devicemapper configuration for RedHat/CentOS
+# docker_devicemapper_raw_device: /dev/sdb
+
+docker_configure_daemon: false
+docker_daemon_config:
+  storage-driver: "devicemapper"
+  storage-opts:
+    - "dm.directlvm_device={{ docker_devicemapper_raw_device|mandatory }}"
+    - "dm.thinp_percent=95"
+    - "dm.thinp_metapercent=1"
+    - "dm.thinp_autoextend_threshold=80"
+    - "dm.thinp_autoextend_percent=20"
+    - "dm.directlvm_device_force=false"

tasks/main.yml

@@ -8,6 +8,14 @@
 - name: Install Docker.
   package: name={{ docker_package }} state={{ docker_package_state }}
 
+- name: Configure docker daemon
+  copy:
+    content: "{{ docker_daemon_config|to_nice_json }}"
+    dest: /etc/docker/daemon.json
+    mode: 0600
+  when: docker_configure_daemon
+  notify: restart docker
+
 - name: Ensure Docker is started and enabled at boot.
   service:
     name: docker