ListHypervisors() fails in v1.4.0

[priteau]

With release v1.4.0 I am getting the following error:

Failed to collect metric for exporter: nova, error: failed to collect metric: running_vms, error: CPUInfo has unexpected type: <nil>" source="exporter.go:122

This impacts 9 metrics that are collected by this function. Since it worked fine in v1.3.0, I tracked it down to the following code:

                microversion, err := apiversions.Get(config.Client, "v2.1").Extract()
                if err == nil {
                                exporter.Client.Microversion = microversion.Version
                }

Removing this code fixes the error.

This is against a Wallaby deployment. Note the following change in Nova API for Wallaby:

2.88 (Maximum in Wallaby)
-------------------------

The following fields are no longer included in responses for the
``GET /os-hypervisors/detail`` and ``GET /os-hypervisors/{hypervisor_id}``
APIs:

- ``current_workload``
- ``cpu_info``
- ``vcpus``
- ``vcpus_used``
- ``free_disk_gb``
- ``local_gb``
- ``local_gb_used``
- ``disk_available_least``
- ``free_ram_mb``
- ``memory_mb``
- ``memory_mb_used``
- ``running_vms``

These fields were removed as the information they provided were frequently
misleading or outright wrong, and many can be better queried from placement.

In addition, the ``GET /os-hypervisors/statistics`` API, which provided a
summary view with just the fields listed above, has been removed entirely and
will now raise a HTTP 404 with microversion 2.88 or greater.

Finally, the ``GET /os-hypervisors/{hypervisor}/uptime`` API, which provided a
similar response to the ``GET /os-hypervisors/detail`` and ``GET
/os-hypervisors/{hypervisor_id}`` APIs but with an additional ``uptime`` field,
has been removed in favour of including this field in the primary ``GET
/os-hypervisors/detail`` and ``GET /os-hypervisors/{hypervisor_id}`` APIs.

[niedbalski]

@alexeymyltsev do you have a wallaby environment to test this on?

[alexeymyltsev]

@alexeymyltsev do you have a wallaby environment to test this on?

@niedbalski unfortunately we do not have Wallaby, for this moment we just on Victoria.
We have one release delay in our environment.

Looks like they move part of hypervisor's metrics to placement.

[alexeymyltsev]

Looks like with below code exporter will use only max version of microversion of Nova API.

	microversion, err := apiversions.Get(config.Client, "v2.1").Extract()
	if err == nil {
		exporter.Client.Microversion = microversion.Version
	}

I think will be better use variable from environment, if it is empty use max version.
OS_COMPUTE_API_VERSION should works.