[gpfsug-discuss] Pmsensors and gui

[valdis.kletnieks at vt.edu]

On Wed, 10 Oct 2018 10:24:58 +0200, "Markus Rohwedder" said:

> Hello Simon,
> 
> not sure if the answer solved your question from the response,
> 
> Even if nodes can be externally resolved by unique hostnames, applications
> that run on the host use the /bin/hostname binary or the hostname() call to
> identify the node they are running on.
> This is the case with the performance collection sensor.
> So you need to set the hostname of the hosts using /bin/hostname in in a
> way that provides unique responses of the "/bin/hostname" call within a
> cluster.

And we discovered that 'unique' applies to "only considering the leftmost part
of the hostname". We set up a stretch cluster that had 3 NSD servers at each of
two locations, and found that using FQDN names of the form:

nsd1.something.loc1.internal
nsd2.something.loc1.internal
nsd1.something.loc2.internal
nsd2.something.loc2.internal

got things all sorts of upset in a very passive-agressive way. The cluster
would come up, and serve data just fine.  But things like 'nsdperf' would toss
errors about not being able to resolve a NSD server name, or fail to connect,
or complain that it was connecting to itself, or other similar "not talking to
the node it thought" type confusion...

We ended up renaming to:

nsd1-loc1.something.internal
nsd1-loc2.something.internal
...

and all the userspace tools started working much better.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 486 bytes
Desc: not available
URL: <http://gpfsug.org/pipermail/gpfsug-discuss_gpfsug.org/attachments/20181010/628fe216/attachment.sig>