[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[LDM #WSX-704500]: RHEL6 netstat not always showing the active LDM connection

This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.

  • Subject: [LDM #WSX-704500]: RHEL6 netstat not always showing the active LDM connection
  • Date: Wed, 24 Apr 2013 10:44:08 -0600
Hi Daryl,

Assuming netstat(1) is working correctly, the only thing I can think of is that 
the downstream LDM on 192.168.0.102 went away because the connection broke and 
then reconnected later.

Does the LDM log file on ...102 show anything for that time period?

> Hi Steve,
> 
> I use 'ldmadmin printmetrics' to monitor the number of upstream hosts to a
> LDM server.  Of course, the number of upstream hosts is determined by a
> netstat call.  What's puzzling is that on my RHEL6.4 64bit KVM hosts, this
> command is not always returning the active socket connection.  For
> example, here is a series of commands run successively.
> 
> [ldm@iemvs102 ~]$ /bin/netstat -A inet -t -n | grep :388
> tcp        0      0 192.168.0.102:57545         192.168.0.21:388
> ESTABLISHED
> [ldm@iemvs102 ~]$ /bin/netstat -A inet -t -n | grep :388
> [ldm@iemvs102 ~]$ /bin/netstat -A inet -t -n | grep :388
> [ldm@iemvs102 ~]$ /bin/netstat -A inet -t -n | grep :388
> [ldm@iemvs102 ~]$ /bin/netstat -A inet -t -n | grep :388
> [ldm@iemvs102 ~]$ /bin/netstat -A inet -t -n | grep :388
> tcp        0      0 192.168.0.102:57545         192.168.0.21:388
> ESTABLISHED
> [ldm@iemvs102 ~]$
> 
> So the same port connection is shown, but it 'disappeared' for a while.
> This while was 10 seconds or so.  Do you have any ideas what is causing
> this to occur?
> 
> The issue is that my monitoring program generates alerts for me when it
> sees the connection as abscent.
> 
> thanks,
> daryl
> 
> --
> /**
> * Daryl Herzmann
> * Assistant Scientist -- Iowa Environmental Mesonet
> * http://mesonet.agron.iastate.edu
> */

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: WSX-704500
Department: Support LDM
Priority: Normal
Status: On Hold