Mount kolla_logs volume in bifrost_deploy

Using a kolla_logs volume ensures that logs are persistent beyond the
lifespan of the bifrost_deploy container. This is necessary to support
upgrading the bifrost services. It also opens the possibility of log
forwarding, although we do not currently deploy a fluentd container on
the bifrost host.

Change-Id: If3118cd75ccc87b0d003d5f382695aeaa43ed0f8
Partially-implements: blueprint bifrost-upgrade

ansible/roles/bifrost/tasks/bootstrap.yml

@@ -1,4 +1,14 @@
 ---
+- name: Ensure log directories exist
+  command: >
+     docker exec bifrost_deploy
+     bash -c 'mkdir -p /var/log/kolla/ironic &&
+     chown ironic:ironic /var/log/kolla/ironic &&
+     mkdir -p /var/log/kolla/ironic-inspector &&
+     chown ironic:ironic /var/log/kolla/ironic-inspector &&
+     mkdir -p /var/log/kolla/nginx &&
+     chown nginx:nginx /var/log/kolla/nginx'
+
 - name: Bootstrap bifrost (this may take several minutes)
   command: >
      docker exec bifrost_deploy

ansible/roles/bifrost/tasks/start.yml

@@ -10,3 +10,4 @@
       - "{{ node_config_directory }}/bifrost/:/etc/bifrost:ro"
       - "/etc/localtime:/etc/localtime:ro"
       - "/dev:/dev"
+      - "kolla_logs:/var/log/kolla/"

ansible/roles/bifrost/templates/bifrost.yml.j2

@@ -1,3 +1,13 @@
+---
+# Ironic log directory.
+ironic_log_dir: "/var/log/kolla/ironic"
+
+# Ironic inspector log directory.
+inspector_log_dir: "/var/log/kolla/ironic-inspector"
+
+# Nginx log directory.
+nginx_log_dir: "/var/log/kolla/nginx"
+
 mysql_service_name: mysql
 ansible_python_interpreter: /var/lib/kolla/venv/bin/python
 network_interface: "{{ bifrost_network_interface }}"

releasenotes/notes/bifrost-persistent-logs-889cb58bf0f22c18.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Adds a ``kolla_logs`` Docker volume for storing logs generated by services
+    running in the ``bifrost_deploy`` container on the deployment host. These
+    logs are not currently processed by fluentd.