[Xymon] 3 vmstat procs and other issues

[Greg Earle]

Way back on 6 Jan 2017, at 3:00, Japeth Cleaver <cleaver at terabithia.org> 
wrote:

> On 1/5/2017 3:18 PM, Galen Johnson wrote:
>
>> Ok...looking more closely at the xymonclient-linux.sh script, it
>> appears that tmpfs was intentionally not included in the exclude
>> list.  At the very least, you may want to consider adding /run to the
>> default excludes in analysis.cfg.  I was also noticing in my df 
>> output
>> that other virtual filesystems were showing (and being tracked) as
>> well, such as /dev/shm and /sys.  I'm not sure why you would want
>> those tracked either.  For example, here's a list of tmpfs "disks" I
>> see on one of my systems:
>>
>> tmpfs                 2033585      9   2033576    1% /dev/shm
>> tmpfs                 2033585    598   2032987    1% /run
>> tmpfs                 2033585     13   2033572    1% /sys/fs/cgroup
>> tmpfs                 2033585     29   2033556    1% /tmp
>> tmpfs                 2033585      1   2033584    1% /run/user/1984
>
> Oy.
>
> I'd forgotten about the newer per-user /run/ environments that were
> coming in now in EL7.  Definitely worth adding specific excludes for 
> those.
>
> /dev/shm/ is occasionally used as dedicated scratch space for some
> purposes.  In fact, it's the default write location for the temporary
> message in the xymon-client RPM for a while now (this way you can
> actually get a report when /tmp/ fills to 100%).  With the 
> proliferation
> of spurious tmpfs mounts now, it might be a good idea to take another 
> look.

Sorry to dredge up an old thread from January, but as I just ran into 
this ...

I agree with Japeth that getting reports about "/tmp" being 100% full is 
a Good Thing™.

But I'm seeing some strange instances on a couple of our RHEL 7.3 
systems where for some strange reason, during boot "/dev/shm" is getting 
mysteriously chmod'ed from mode 1777 to 1755.  No idea why/where.

Xymon starts up OK but of course it can't write its temp files in there 
so everything goes Purple and "stopped reporting".  Took me a while to 
suss that one out.  (This mystery chmod'ing also affects "gdm" as 
"pulseaudio" can't write its tmp files in there either.)

Not sure what the best solution is (I assume if you put them in 
"/var/tmp" or "/var/run/xymon" then if "/var" is part of "/", you 
wouldn't get 100% full alerts for "/" - which would be a Bad Thing™), 
but thought I should mention this scenario.

I might try changing XYMONTMP in "xymonclient.cfg" on this latest system 
where it happened just to test it out, but it's a VM with little chance 
of "/" filling up.

BTW, I just noticed there's a "/run/xymon" (in the RHEL 7.3 RPM, 
anyway).  Why not use that for XYMONTMP on RHEL 7/CentOS 7/Fedora?  Or 
would it be too much of a pain to maintain two different 
"xymonclient.cfg" files with two different XYMONTMP settings?

		- Greg

P.S. Need Fedora 26 RPMs for 4.3.28 please :)