link kolla_logs volume to docker_runtime_directory if docker_runtime_directory variable exists

Change-Id: I053c4a47e657effe25e8d75a3ef55477635729d2

ansible/group_vars/all.yml

@@ -94,6 +94,7 @@ docker_registry:
 docker_namespace: "kolla"
 docker_registry_username:
 docker_registry_insecure: "{{ 'yes' if docker_registry else 'no' }}"
+docker_runtime_directory: ""
 
 # Retention settings for Docker logs
 docker_log_max_file: 5

ansible/roles/baremetal/defaults/main.yml

@@ -66,8 +66,6 @@ docker_storage_driver: ""
 
 docker_custom_option: ""
 
-docker_runtime_directory: ""
-
 # Ubuntu 18+ does not have easy_install available due to
 # https://bugs.launchpad.net/ubuntu/+source/python-setuptools/+bug/1774419.
 easy_install_available: >-

ansible/roles/common/tasks/bootstrap.yml

@@ -9,6 +9,6 @@
 - name: Link kolla_logs volume to /var/log/kolla
   become: true
   file:
-    src: /var/lib/docker/volumes/kolla_logs/_data
+    src: "{{ docker_runtime_directory or '/var/lib/docker' }}/volumes/kolla_logs/_data"
     path: /var/log/kolla
     state: link