on bhyve statistics

[Marcelo Araujo]

Hi Fabian,

2018-08-27 22:14 GMT+08:00 Fabian Freyer <fabian.freyer at physik.tu-berlin.de>
:

> Hi list,
>
> I'm currently looking at getting the libvirt prometheus exporter[1] to
> work with libvirt+bhyve. In its current state this doesn't work because
> at least one of the API calls exposed by libvirt isn't implemented by
> the libvirt bhyve driver - so I started looking at implementing it.
>
> The first API call in question is virDomainBlockStats[2], which returns
> statistics (number of read and written bytes and ops, respectively).
>
> Currently, bhyve does not expose any of these statistics. All the stats
> available through bhyvectl --get-stats seem to be coming from the VMM,
> not from the userspace emulation. OTOH, I did see that there are *some*
> stats being collected in bhyverun.c (see struct bhyvestats {...}
> stats;). I can't see how these are exposed though -  a grep of /usr/src
> turned up no other uses. Which brings me to the following questions:
>
> - are the stats in struct bhyvestats {...} stats exposed or used in any
>   non-obvious way?
>

They are most used inside bhyverun by the name "stats" and the purpose is
not really to collect statistics about the guest vm.


>
> - architecturally, what would be the best ways to get stats out of the
>   user-space emulations? Off of the top of my head, I could think of the
>   following possibilities:
>   - prometheus exporter
>   - having some socket or pipe to request them
>   - DTrace probes
>

I don't know what kind of stats do you need to collect, but based on the
assumptions you listed above, maybe you can take a look at this project:
https://github.com/freenas/bhyve-vm-goagent

bhyve-vm-goagent can easily be extended to collect other information from
guest. Although I'm not sure if it will be useful for your case, looks like
you are looking for something less intrusive than bhyve-vm-goagent.



>
> I wouldn't mind implementing any of the above, and so would like to know
> which of these (or other options) would be the most acceptable, and
> would appreciate some guidance.
>
> CC'ing novel@ for the libvirt side, and grehan@ for the architectural
> bhyve questions.
>
> Fabian
>
> [1] https://github.com/kumina/libvirt_exporter
> [2] https://libvirt.org/html/libvirt-libvirt-domain.html#
> virDomainBlockStats
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-- 

-- 
Marcelo Araujo            (__)araujo at FreeBSD.org
\\\'',)http://www.FreeBSD.org <http://www.freebsd.org/>   \/  \ ^
Power To Server.         .\. /_)