Support setting Nova API microversion for openstack-exporter

Starting from v1.5.0 of the exporter, OS_COMPUTE_API_VERSION can be set
to configure the Nova API version to be used [1]. Microversion 2.1 can
be used to keep metrics unmodified from the previous exporter version
deployed by Kolla (v1.3.0).

Support it with prometheus_openstack_exporter_compute_api_version,
defaulting to using version 2.1 to keep metrics unchanged.

[1] https://github.com/openstack-exporter/openstack-exporter/pull/201

Change-Id: I7605a3f9f74effb29ecec3b28e4709fd5f7f8cd4
(cherry picked from commit 41fba3c5df)
(cherry picked from commit 5cc47b02da)

ansible/group_vars/all.yml

@@ -1128,6 +1128,7 @@ prometheus_elasticsearch_exporter_interval: "60s"
 prometheus_cmdline_extras:
 prometheus_ceph_mgr_exporter_endpoints: []
 prometheus_openstack_exporter_endpoint_type: "internal"
+prometheus_openstack_exporter_compute_api_version: "2.1"
 prometheus_libvirt_exporter_interval: "60s"
 
 ############

ansible/roles/prometheus/defaults/main.yml

@@ -75,6 +75,8 @@ prometheus_services:
     container_name: "prometheus_openstack_exporter"
     group: "prometheus-openstack-exporter"
     enabled: "{{ enable_prometheus_openstack_exporter | bool }}"
+    environment:
+      OS_COMPUTE_API_VERSION: "{{ prometheus_openstack_exporter_compute_api_version }}"
     image: "{{ prometheus_openstack_exporter_image_full }}"
     volumes: "{{ prometheus_openstack_exporter_default_volumes + prometheus_openstack_exporter_extra_volumes }}"
     dimensions: "{{ prometheus_openstack_exporter_dimensions }}"

ansible/roles/prometheus/handlers/main.yml

@@ -117,6 +117,7 @@
     image: "{{ service.image }}"
     volumes: "{{ service.volumes }}"
     dimensions: "{{ service.dimensions }}"
+    environment: "{{ service.environment|default(omit) }}"
   when:
     - kolla_action != "config"
 

ansible/roles/prometheus/tasks/check-containers.yml

@@ -9,6 +9,7 @@
     pid_mode: "{{ item.value.pid_mode|default('') }}"
     volumes: "{{ item.value.volumes }}"
     dimensions: "{{ item.value.dimensions }}"
+    environment: "{{ item.value.environment|default(omit) }}"
   when:
     - inventory_hostname in groups.get(item.value.group, [])
     - item.value.enabled | bool

releasenotes/notes/openstack-exporter-nova-version-9e75cb7ec04658f2.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - |
+    Adds support for configuring the Openstack Compute API microversion used by
+    the OpenStack exporter for Prometheus using the
+    ``prometheus_openstack_exporter_compute_api_version`` variable. The default
+    value is ``2.1`` to keep metrics unchanged when using recent exporter
+    releases.