Add a configuration about docker runtime directory

Control the disk space used for Docker images, containers and
volumes is important for us.We need add configuration of
docker daemon to control the disk spaces used for docker images,
containers and volumes.

Change-Id: I3cf99f4e3f62c8406d37201b1cc24a83c68e3b27
Signed-off-by: pengdake <19921207pq@gmail.com>

ansible/roles/baremetal/defaults/main.yml

@@ -16,6 +16,8 @@ disable_selinux: True
 
 docker_storage_driver: ""
 
+docker_runtime_directory: ""
+
 debian_pkg_install:
  - "{{ 'docker-ce' if ansible_architecture == 'aarch64' else 'docker-engine=1.12.*' }}"
  - git

ansible/roles/baremetal/templates/docker_systemd_service.j2

@@ -1,4 +1,4 @@
 [Service]
 MountFlags=shared
 ExecStart=
-ExecStart=/usr/bin/{{ docker_binary_name|default("docker daemon", true) }}{% if docker_registry %} --insecure-registry {{ docker_registry }}{% endif %}{% if docker_storage_driver %} --storage-driver {{ docker_storage_driver }}{% endif %}
+ExecStart=/usr/bin/{{ docker_binary_name|default("docker daemon", true) }}{% if docker_registry %} --insecure-registry {{ docker_registry }}{% endif %}{% if docker_storage_driver %} --storage-driver {{ docker_storage_driver }}{% endif %}{% if docker_runtime_directory %} --graph {{ docker_runtime_directory }}{% endif %}

releasenotes/notes/support-docker-runtime-directory-set-da7e77a70626c0d1.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    Set docker runtime directory by configure the docker daemon.An operator
+    named "docker_runtime_directory" will be add.