Include XO tags in OpenMetrics metrics

[tesarmar]

Currently, the Xen Orchestra OpenMetrics exporter does not include object tags
(hosts, VMs, etc.) as metric labels.

This makes it difficult or impossible to selectively monitor resources in external
systems such as Zabbix, Prometheus, or Grafana, especially in MSP or multi-tenant
environments where tagging is commonly used for scoping.

Current limitation

For example, xcp_host_status exposes labels like:

• uuid
• host_name
• pool_name
• power_state
• enabled

But it does not expose any tag-related information, even though tags are available
in XO.

Proposed improvement

Include tags as an additional label, for example:
tags="tag1,tag2,tag3"

Ideally for:

• hosts (xcp_host_*)
• VMs (xcp_vm_*)
• (optionally) storage repositories

Benefits

• enables filtering and scoping in external monitoring systems
• reduces noise by allowing selective discovery
• aligns with common Prometheus/OpenMetrics practices
• no breaking change (additional label only)

Example use cases

• monitor only resources tagged production
• separate customers in MSP environments
• exclude lab/test systems from monitoring

[mpiton]

Hi @tesarmar,
Thanks for this detailed feature request. The use cases you describe (MSP scoping, production filtering, etc.) make a lot of sense.
We've added this feature to our roadmap and plan to work on it in the coming months. The current thinking is to expose tags as a comma-separated label (e.g. tags="tag1,tag2,tag3") on host, VM, and SR metrics. This keeps things compatible with the OpenMetrics format while allowing regex-based filtering in Prometheus/Grafana ({tags=~".*production.*"}).
We'll update this issue as we make progress. Feel free to share any additional thoughts in the meantime.