[Xymon] no client results arrive, lot of TIME_WAIT at server

Fri Oct 20 02:19:32 CEST 2017

Is this a shared memory issue (shm) - the process can't allocate shared memory? Maybe increase the SHMALL kernel parameter?

________________________________

Hi Thomas,

thank you for your hints.
Lets go through your suggestions:

- you were right with the INTERVAL. This was added by accident, but doesn't harm (no more channels are started), removed, no effect
- yes, server process was restartet at 5:13am UTC

1.
- environment looks as expected:
$ xymoncmd /usr/bin/env | egrep -i 'xymsrv|xymonservers|bbdisp'
XYMONSERVERS=10.137.56.43
XYMSRV=10.137.56.43
BBDISP=10.137.56.43
BBDISPLAYS=10.137.56.43

2.
- unfortunately i don't have root access here for a tcpdump

3.
- now it gets strange:
if i try your suggestion i get this (doublechecked at other server and the syntax works ok):

$ xymoncmd xymond_channel --channel=client cat
2017-10-19 15:58:58.843500 execvp() failed: No such file or directory
(but of curse xymoncmd is in the path)

if i try with relative path i get this (run from bin path):
$ ./xymoncmd ./xymond_channel --channel=client cat
2017-10-19 16:01:02.173601 Could not get shm of size 524288: No such file or directory
2017-10-19 16:01:02.173943 Channel not available

some of these messages i can find in some logs:

$ grep "Could not get shm" *
alert.log:2017-10-19 10:38:00.733526 Could not get shm of size 1048576: No such file or directory
history.log:2017-10-19 10:38:00.730686 Could not get shm of size 1048576: No such file or directory
hostdata.log:2017-10-19 10:38:00.730538 Could not get shm of size 524288: No such file or directory
rrd-data.log:2017-10-19 10:38:00.734198 Could not get shm of size 524288: No such file or directory

I searched the web for those messages, and found some in hobbit/xymon mailing list, but no details or solution.
http://lists.xymon.com/oldarchive/2008/06/msg00183.html

But: the client messages from server still arrive and the tests are all visible...
very strange

Norbert

[Inactive hide details for Thomas Eckert ---19/10/2017 16:42:24---> On 19 Oct 2017, at 14:49, Norbert Kriegenburg <norbert.krieg]Thomas Eckert ---19/10/2017 16:42:24---> On 19 Oct 2017, at 14:49, Norbert Kriegenburg <norbert.kriegenburg at de.ibm.com> wrote: >

From: Thomas Eckert <thomas.eckert at it-eckert.de>
To: xymon <xymon at xymon.com>
Date: 19/10/2017 16:42
Subject: Re: [Xymon] no client results arrive, lot of TIME_WAIT at server
Sent by: "Xymon" <xymon-bounces at xymon.com>

________________________________

On 19 Oct 2017, at 14:49, Norbert Kriegenburg <norbert.kriegenburg at de.ibm.com<mailto:norbert.kriegenburg at de.ibm.com>> wrote:

Yes,
that's what i checked at first. But i assume that also the info from the servers own client data are captured by the same client channel listener, and that obviously works.

valid point

Nothing in the clientdata.log, even if i activate the DEBUG mode with a
kill -USR2 PID

My clientdata section:
# The client back-end module. You need this if you are running the Xymon client on any system.
[clientdata]
ENVFILE $XYMONSERVERHOME/etc/xymonserver.cfg
NEEDS xymond
CMD /home/xymon/server/bin/xymond_channel --channel=client \
--log=$XYMONSERVERLOGS/clientdata.log xymond_client \
--no-clear-files \
--no-clear-ports \
--no-port-listing \
--uptime-status
INTERVAL 2m

The `INTERVAL` here is not im my and xymon.com<http://xymon.com/>’s-version of tasks.cfg— not sure if it does harm (it _may_ try to start a new channel every 2 minutes).

ps listing:
$ ps -ef|grep "xymond_channel --channel=client"|grep -v grep
xymon 18865 18705 0 05:13 ? 00:00:00 /home/xymon/server/bin/xymond_channel --channel=client --log=/home/xymon/server/logs/clientdata.log xymond_client --no-clear-files --no-clear-ports --no-port-listing --uptime-status

If this process does not change it should be fine; your xymon server was restarted 5:13 this morning?

I have a lot of TIME_WAITS from time to time, no idea why this goes up and down:

$ netstat -atn|grep 1984
tcp 0 0 0.0.0.0:1984 0.0.0.0:* LISTEN
tcp 0 0 10.137.56.43:37752 10.137.56.43:1984 TIME_WAIT
tcp 0 0 10.137.56.43:37822 10.137.56.43:1984 TIME_WAIT
...

10.137.56.43 is the Xymon server IP.

$ netstat -atn|grep 1984|wc -l
165
(sometimes much much more)

(But goes down to 7 after some mins)

Looks like internal xymon-communication. As long as the TIME_WAIT-count does not go >20k that should not be the cause.

Thing’s I’d try from here:

1. double-check the XYMSRV / XYMONSERVERS setting on the client(s), e.g. with:

xymoncmd /usr/bin/env | egrep -i 'xymsrv|xymonservers|bbdisp’

2. just to double-check: tcpdump on xymon server and a client to check for tcp/1984 communication

3. run a channel-listener an the server to see if the client messages (other than the ones from the local client) make it

xymoncmd xymond_channel --channel=client cat | grep ‘^client '
xymoncmd xymond_channel --channel=client cat

The latter might be very noisy — the former just prints the “header”/1st line of each connection.
There should be one message for each client sending data every 5 minutes.

HTH
Thomas

<graycol.gif>Thomas Eckert ---19/10/2017 11:14:56---Norbert, I assume your manual (BB way) is something like `xymon 1.2.3.4 “status example.com.test …”`

From: Thomas Eckert <thomas.eckert at it-eckert.de<mailto:thomas.eckert at it-eckert.de>>
To: xymon <xymon at xymon.com<mailto:xymon at xymon.com>>
Date: 19/10/2017 11:14
Subject: Re: [Xymon] no client results arrive, lot of TIME_WAIT at server
Sent by: "Xymon" <xymon-bounces at xymon.com<mailto:xymon-bounces at xymon.com>>

________________________________

Norbert,

I assume your manual (BB way) is something like `xymon 1.2.3.4 “status example.com.test …”`.

The xymon-client send `clientdata` that is processed by a “channel listener” and _that_ sends status-messages similar to above (a bit simplified).

That channel-listener may not be running/crashing:
Check our `tasks.cfg` for the section `[clientdata]` and verify, if the `xymond_channel`-process is running (I suspect it’s not). Maybe the `clientdata.log` helps with debugging. You may also run the task manually to get further information.

What’s your problem with the "lot of TIME_WAIT”? Are these just for tcp/1984-connections?

Cheers
Thomas
On 19 Oct 2017, at 07:30, Norbert Kriegenburg <norbert.kriegenburg at de.ibm.com<mailto:norbert.kriegenburg at de.ibm.com>> wrote:

experts,

i have a new (not my first) Xymon installation (4.3.28 on RH 7.4, self compiled).
All looks good, but the clients only show the network tests (conn, ssh). Only the Xymon server itself shows everything (disk, cpu,...).
- all clients are RH 7.4, same install image used (i just copied over the client part with client config, create a cronjob for automatic start, so no root access nor extra install needed)
- nothing suspicious in server or client logs (even in debug mode)
- no ghosts
- if i send a test manually (the old BB way) this shows at Xymon immediately (so the client settings are ok)
- if i shutdown the xymond at server, the client logs complains:

2017-10-19 05:09:18.051994 Whoops ! Failed to send message (Connection failed)
2017-10-19 05:09:18.052104 -> Could not connect to Xymon daemon at 10.137.56.43<mailto:daemon at 10.137.56.43>:1984 (Connection refused)

(so obviously they communicate)

Querying the xymond shows:
xymon 127.0.0.1 "query clientname.ssh"
green <!-- [flags:OrdastLe] --> Thu Oct 19 05:21:29 2017 ssh ok
is ok, but
xymon 127.0.0.1 "query clientname.disk"
shows nothing

Any ideas?

Norbert

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