[Xymon] xymonnet timeouts?

[Richard Hamilton]

In this case, "dialup" isn't literal, they're VMs under type II (hosted)
hypervisors - VirtualBox or Parallels, in this case.  Since the hosts don't
have gigantic amounts of RAM, the VMs are only brought up when needed
(testing, development, updates, or nostalgia for some other OS); but when
up, should be healthy, with all their usual services running.

Another dialup is my laptop, which is usually where I am, not necessarily
back home with the xymon server. :-)  Since it has neither builtin cellular
nor do I have an always-on portable cellular hotspot (although the phone
can do that duty occasionally in the absence of a proper one), there's no
way for it to be connected all the time, either.

Likewise, some non-infrastructure devices are dialup, because they're not
on all the time - like a WiFi picture frame, various iDevices, or a game
console.  If the printer didn't have energy saver mode, it would be a
dialup too, because it wouldn't be left on all the time.

Literal dialup with a modem may be rare enough nowadays, but there are
plenty of modern intermittently connected cases for which the functionality
is still useful, IMO.

One way or another, exposing a way to have network tests contingent on
basic connectivity, even when basic connectivity is optional (dialup),
would IMO help, a lot - especially for external tests, of which rpc is the
worst - ntp timeout is very quick by comparison; and RPC libraries come in
different enough flavors that rolling a portable version of rpcinfo with a
timeout option seems a bit tedious (I've looked at e.g. Solaris and Mac
code for rpcinfo, and they're very different internally; the Mac's seems
derived from a really old BSD flavor, more or less).


On Wed, Feb 15, 2017 at 11:35 AM, Japheth Cleaver <cleaver at terabithia.org>
wrote:

> On 2/15/2017 7:50 AM, Richard Hamilton wrote:
>
> I noticed I was getting these when a host (marked dialup) was down; turns
> out it's because there was an RPC test, and rpcinfo has no option to choose
> a reasonable timeout; trying to run it against a host that's down or
> unreachable takes nearly ten minutes to time out!
>
> What I don't understand, is why, given the conn test was enabled and not
> green or yellow, it was trying to do other network tests on that host.
>
> Here's the host line:
> 192.168.0.56 lapple-sierra # dialup CLIENT:lapple-sierra.pri
> noflap=location ssh ntp rpc=mountd,nlockmgr,nfs,rpcbind,rquotad,status
> NOCOLUMNS:files multihomed NOPROPPURPLE:+location
> NOPROPYELLOW:+cpu,+location
>
> (location is an client extension script, not relevant to the problem at
> hand)
>
>
> Interestingly, this appears to be intentional -- dialup tests are not
> considered "down" internally (clear is N/A more than a down state) and so
> they aren't bypassed later in the cycle when we get to running rpcinfo.
>
> I'm not entirely certain on the history here. This smells like it should
> be a bug for precisely the reason you're seeing. Mass timeouts testing
> against things that are down. OTOH, there may be cases where things are
> intermittently unpingable and yet people are expecting other testing to
> continue on. 'dialup' is a bit lesser used nowadays, which may be why this
> is less frequently hit.
>
> There's logic in xymonnet that allows for internal flagging of something
> as actually up or down for purposes of testing (to handle things like
> badconn); this should probably become an option for control in the future.
>
> Regards,
> -jc
>
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