Use openstack_version to determine Journalbeat hosts

Systemd journals are linked from the containers down to the hosts
starting in Rocky. Prior to this Journalbeat must also be on all
containers.

Change-Id: Iaaef19e76c40ba9c1ad58164c20da46766abeee6

elk_metrics_6x/installJournalbeat.yml

@@ -13,8 +13,34 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+- name: Detect journalbeat host deployment group(s)
+  hosts: all
+  gather_facts: false
+  connection: local
+  tasks:
+    - name: Add hosts to dynamic inventory group
+      group_by:
+        key: journalbeat_deployment_containers
+        parents: all_journalbeat_deployments
+      when:
+        - openstack_release is defined and
+          openstack_release is version('18.0.0', 'lt')
+        - physical_host is defined and
+          physical_host != inventory_hostname
+
+    - name: Add hosts to dynamic inventory group
+      group_by:
+        key: journalbeat_deployment_hosts
+        parents: all_journalbeat_deployments
+      when:
+        - physical_host is defined and
+          physical_host == inventory_hostname
+
+  tags:
+    - always
+
 - name: Install Journalbeat
-  hosts: hosts
+  hosts: all_journalbeat_deployments
   become: true
   vars:
     haproxy_ssl: false

elk_metrics_6x/readme.rst

@@ -319,6 +319,11 @@ deploy logstash, deploy Kibana, and then deploy all of the service beats.
 * The `openstack-ansible` command can be used if the version of ansible on the
   system is greater than **2.5**.
 
+* If required add ``-e@/opt/openstack-ansible/inventory/group_vars/all/all.yml``
+  to import sufficient OSA group variables to define the OpenStack release.
+  Journalbeat will then deploy onto all hosts/containers for releases prior to
+  Rocky, and hosts only for Rocky onwards. If the variable ``openstack_release``
+  is undefined the default behaviour is to deploy Journalbeat to hosts only.
 
 The individual playbooks found within this repository can be independently run
 at anytime.