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SNMP log file

Posted: Tue Apr 30, 2019 7:50 am
by Ludvik
Hi.

I noticed that the /var/log/snmpd.log file is 11 MB big on my switch.
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admin@curve1:/www# ls -l /var/log
-rw-r--r-- 1 admin root 0 Jan 1 1970 lastlog
drwxr-xr-x 2 admin root 0 Mar 25 01:20 lighttpd
-rw-r--r-- 1 admin root 245 Apr 29 18:06 messages
drwxr-xr-x 2 admin root 0 Mar 25 01:20 radius
-rw-r--r-- 1 admin root 11028919 Apr 30 13:41 snmpd.log
-rw-r--r-- 1 admin root 0 Jan 1 1970 wtmp

Contains a large number of records:
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No MemShared line in /proc/meminfo

It is always created after querying OID .1.3.6.1.4.1.2021.4.6.0

What happens when the free space is completely occupied?
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Filesystem Size Used Available Use% Mounted on
rootfs 5.8M 5.8M 0 100% /
/dev/root 5.8M 5.8M 0 100% /rom
/dev/mtdblock6 4.3M 1.2M 3.0M 28% /jffs
mini_fo:/jffs 5.8M 5.8M 0 100% /

Re: SNMP log file

Posted: Tue Apr 30, 2019 2:25 pm
by Stephen
Would you mind running the command:
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cat /var/log/snmpd.log


And sharing the output?

I'm wondering if this might be another piece to the puzzle on the other issue we're dealing with that seems to be related to discovery.

Re: SNMP log file

Posted: Tue Apr 30, 2019 2:56 pm
by Ludvik
317632 lines ...

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Cannot find module (IP-MIB): At line 0 in (none)
Cannot find module (IF-MIB): At line 0 in (none)
Cannot find module (TCP-MIB): At line 0 in (none)
Cannot find module (UDP-MIB): At line 0 in (none)
Cannot find module (HOST-RESOURCES-MIB): At line 0 in (none)
Cannot find module (SNMPv2-MIB): At line 0 in (none)
Cannot find module (SNMPv2-SMI): At line 0 in (none)
Cannot find module (NOTIFICATION-LOG-MIB): At line 0 in (none)
Cannot find module (SNMP-VIEW-BASED-ACM-MIB): At line 0 in (none)
Cannot find module (SNMP-COMMUNITY-MIB): At line 0 in (none)
Cannot find module (SNMP-FRAMEWORK-MIB): At line 0 in (none)
Cannot find module (SNMP-MPD-MIB): At line 0 in (none)
Cannot find module (SNMP-USER-BASED-SM-MIB): At line 0 in (none)
Cannot find module (TUNNEL-MIB): At line 0 in (none)
Cannot find module (UCD-DLMOD-MIB): At line 0 in (none)
Cannot find module (IPV6-ICMP-MIB): At line 0 in (none)
Cannot find module (IPV6-MIB): At line 0 in (none)
Cannot find module (IPV6-TCP-MIB): At line 0 in (none)
Cannot find module (IPV6-UDP-MIB): At line 0 in (none)
Error opening specified endpoint "udp:161"
Server ExitingNo MemShared line in /proc/meminfo
No MemShared line in /proc/meminfo

... last line repeated 317610x (as I said).

Other piece of switch: 883756 lines.
---

I do not have this monitoring on all of netonixes. These pieces have snmp log almost empty. This is *probably* not our memory problem.

Re: SNMP log file

Posted: Tue Apr 30, 2019 3:24 pm
by Stephen
Sorry I know you did say that, I just wanted to see the difference between what I'm seeing on mine and this one.

The only lines that are different are these:

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Error opening specified endpoint "udp:161"
Server ExitingNo MemShared line in /proc/meminfo
No MemShared line in /proc/meminfo


On mine, the very next line should be:
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NET-SNMP version 5.1.2


It appears that port 161 is already being used by something which is blocking snmpd from starting, possibly causing it to continuously restart. Or, it is locking it into a error state and whenever it is queried it shows that error message.

See if you can get the output for the following:
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ps | grep snmp


On mine, the result should be
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969 admin     5292 S    /usr/sbin/snmpd -Lf /dev/null -p /var/run/snmpd.pid


Also, to be safe, there should be no severe consequence if you remove that log file, it will just re-create it when it needs it:
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rm /var/log/snmpd.log

Re: SNMP log file

Posted: Tue Apr 30, 2019 4:14 pm
by Ludvik
snmpd is running. I have graphs ... you see it in other thread. IP 10.106.30.74 is visible in graph header. 1.5.2rc6
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 1083 admin 5488 S /usr/sbin/snmpd -Lf /dev/null -p /var/run/snmpd.pid


This is another switch, also monitored (1.5.0), 884063 lines:
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Cannot find module (IP-MIB): At line 0 in (none)
Cannot find module (IF-MIB): At line 0 in (none)
Cannot find module (TCP-MIB): At line 0 in (none)
Cannot find module (UDP-MIB): At line 0 in (none)
Cannot find module (HOST-RESOURCES-MIB): At line 0 in (none)
Cannot find module (SNMPv2-MIB): At line 0 in (none)
Cannot find module (SNMPv2-SMI): At line 0 in (none)
Cannot find module (NOTIFICATION-LOG-MIB): At line 0 in (none)
Cannot find module (SNMP-VIEW-BASED-ACM-MIB): At line 0 in (none)
Cannot find module (SNMP-COMMUNITY-MIB): At line 0 in (none)
Cannot find module (SNMP-FRAMEWORK-MIB): At line 0 in (none)
Cannot find module (SNMP-MPD-MIB): At line 0 in (none)
Cannot find module (SNMP-USER-BASED-SM-MIB): At line 0 in (none)
Cannot find module (TUNNEL-MIB): At line 0 in (none)
Cannot find module (UCD-DLMOD-MIB): At line 0 in (none)
NET-SNMP version 5.1.2
No MemShared line in /proc/meminfo
...


Deleting file is only temporary solution (but file is not recreated). You need solve error and implementing logrotate.

Re: SNMP log file

Posted: Tue Apr 30, 2019 6:03 pm
by Ludvik
It was not re-created after deleting the log file. I tried "kill -HUP" and hoped to reload the configuration and create a log file.
But the process was killed ... and after a few seconds started: Apr 30 23:49:30 monitor: restarting snmpd

However, I was very surprised at the status of RAM occupation. Instead of 106MB, now only 74!

10_106_212_18__1_3_6_1_4_1_2021_4_6_0-hour.png


I myself wonder what will eventually be a mistake. Later I try it on another switch.

Re: SNMP log file

Posted: Tue Apr 30, 2019 6:28 pm
by Ludvik
Test on 10.106.30.74

The CPU usage is strange. I didn't do anything, just checked the log file and got the WEB-GUI open. I would like the htop program to be part of the firmware.

status_page.png

processes.png


At this state i remove log file and reload snmpd.
kill.png


Result:
after_snmpd_reload.png


---
My management system also simply check STP root port and bridge. OID .1.3.6.1.2.1.17.2.5.0. Before reload snmpd it has value 65535 as root port and own MAC as root bridge. After reload it is port 0 and 00:00:00:00:00:00 as root bridge. I have STP disabled. It is strange.

Re: SNMP log file

Posted: Tue Apr 30, 2019 6:35 pm
by Stephen
Well part of this I suspected actually - I am really beginning to suspect that the issue we've been attributing to discovery may actually have to do with snmpd.

The error:
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    No MemShared line in /proc/meminfo


Is probably happening because when your snmp client is querying the device for OID .1.3.6.1.4.1.2021.4.6.0
Which, is the amount of free memory available, net-snmp might be trying to make a call to a MemShared variable in meminfo which does not exist on the version of the kernel we have to use. I took a look around and apparently this is not an unknown possibility with net-snmp.

I think we may very well have found the source of the memory leak we've been hunting.