Gather CPU utilization of host as variable for prometheus exporter
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Everything is already exported via RRDs (see https://wiki.xenproject.org/wiki/XAPI_RRDs). That's what we use in XO.
But this is far from being nice because:
- Those RRDs are encapsulated in XML, which is costly to parse
- XAPI itself is hammering Xen with requests every 5 secs
So ideally, doing a metrics redesign from Xen to XAPI first, will be better.
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how does API get these metrics?
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You mean how XAPI is fetching these metrics?
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@olivierlambert yes
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there must be some low level way to do that from dom0
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That's the plan, yes, there's some Xen stats backend, but it requires some work to modify Xen for a better system.
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I just installed XCP-ng on a new server and wanted Prometheus metrics too, so I wrote this: https://github.com/MikeDombo/xen-exporter.
It is a simple Python script (which can run in Docker) that collects the metrics from XCP-ng's RRD API. These are the same metrics that you'd see in Xen Orchestra or in the XenServer Console application. In addition to the exporter, I've also created a Grafana dashboard to visualize these metrics too.
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Ah nice!
Ideally, we'd like to avoid to use the complicated XAPI RRD + XML system. See https://xcp-ng.org/blog/2022/05/25/fetching-metrics-in-xen-why-the-method-matters/
Thanks a lot to bring this, I'll promote it!
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I was about to link Mike's work here, but wanted to say how we desperately need a metrics system that would be exposed from a centralized location. There's no way in hell I'm giving a docker host credential access to the hypervisor it resides on (and all the other hypervisors) - on the other hand, if the metrics were exposed only via XO and limited in terms of where these metrics could be accessed from, now that would be a sold implementation.
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