Use Nova API 2.79 in openstack-exporter queries

Nova API version 2.88 removed details from the os-hypervisors API [1].
These details are queried by openstack-exporter for metrics such as
openstack_nova_running_vms. However, a change between v1.3.0 and v1.4.0
of the exporter caused it to use the latest API version, breaking
collection of these metrics [2].

Starting from v1.5.0 of the exporter, OS_COMPUTE_API_VERSION can be set
to configure the Nova API version to be used. Set it to 2.79 (maximum in
Train), which also fixes an issue displaying the flavor ID [4].

[1] https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#maximum-in-wallaby
[2] openstack-exporter/openstack-exporter#191
[3] openstack-exporter/openstack-exporter#201
[4] openstack-exporter/openstack-exporter#220

Change-Id: I7605a3f9f74effb29ecec3b28e4709fd5f7f8cd4

ansible/group_vars/all.yml

@@ -1118,6 +1118,7 @@ prometheus_elasticsearch_exporter_interval: "{{ prometheus_scrape_interval }}"
 prometheus_cmdline_extras:
 prometheus_ceph_mgr_exporter_endpoints: []
 prometheus_openstack_exporter_endpoint_type: "internal"
+prometheus_openstack_exporter_compute_api_version: "2.79"
 prometheus_libvirt_exporter_interval: "60s"
 
 ############

ansible/roles/prometheus/defaults/main.yml

@@ -76,6 +76,8 @@ 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[item.value.group]
     - item.value.enabled | bool

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

@@ -0,0 +1,13 @@
+---
+features:
+  - |
+    Adds support for configuring the Nova API microversion used by the
+    OpenStack exporter for Prometheus using the
+    ``prometheus_openstack_exporter_compute_api_version`` variable. Its default
+    value is ``2.79`` to keep some metrics which became unavailable in
+    `microversion 2.88
+    <https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#maximum-in-wallaby>`__.
+upgrade:
+  - |
+    Some metrics provided by the OpenStack exporter for Prometheus may change
+    or become unavailable based on the API microversion being used.