[ZBX-23198] nexus 9000 snmp flood Created: 2023 Aug 03  Updated: 2023 Nov 15  Resolved: 2023 Aug 04

Status: Closed
Project: ZABBIX BUGS AND ISSUES
Component/s: None
Affects Version/s: 6.4.4, 6.4.5
Fix Version/s: None

Type: Problem report Priority: Trivial
Reporter: Boqian Zhang Assignee: Zabbix Support Team
Resolution: Won't fix Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified
Environment:

Software
BIOS: version 06.26
NXOS: version 6.1(2)I2(2b)
BIOS compile time: 01/15/2014
NXOS image file is: bootflash:///n9000-dk9.6.1.2.I2.2b.bin
NXOS compile time: 8/7/2014 17:00:00 [08/08/2014 08:10:31]

Hardware
cisco Nexus9000 C9508 (8 Slot) Chassis ("Supervisor Module")

Attachments: PNG File screenshot-1.png    
Issue Links:
Duplicate

 Description   

Here is the steps to reproduce the issue with the SNMP packets, 

  1. Use the Cisco IOS by SNMP template to monitor a Cisco Nexus 9000 device.
  2. Observe that the SNMP packet count on the device is 100 packets per minute.
  3. Use the Cisco Nexus 9000 Series by SNMP template to monitor a Cisco Nexus 9000 device.
  4. Observe that the SNMP packet count on the device is also 100 packets per minute.
  5. Disable monitoring for the devices in Zabbix.
  6. Observe that the SNMP packet count on the devices goes back to normal.

The issue is that Zabbix is sending too many SNMP packets to the devices. This is causing the devices to become overloaded.

In Zabbix 4.0, the SNMP packet count for the Cisco IOS by SNMP template is around 10 packets per minute (same nexus 9000 device). This is a more reasonable number, and it does not cause the devices to become overloaded.

The following are some possible solutions to the issue:

  • Upgrade SNMP template that sends fewer packets.
  • Configure Zabbix to poll the devices less frequently.

We are not sure why Zabbix is sending so many SNMP datagrams to the Nexus 9000 device.

 

 Comments   
Comment by Boqian Zhang [ 2023 Aug 03 ]

I turned off the auto-discovery in the device configuration and kept other items triggers enabled. SNMP values are normal now. The problem was that the auto-discovery function sent too many SNMP packets to the device.

Comment by Boqian Zhang [ 2023 Aug 03 ]

This method does not work in 6.4.5. I used two templates, and the number of SNMP packets still increases rapidly to about 30 per second even when the auto-discovery feature is disabled. 

Comment by Boqian Zhang [ 2023 Aug 03 ]

all mintue = second
sorry for that

Comment by Edgar Akhmetshin [ 2023 Aug 04 ]

Unfortunately any monitoring system is not able to get metrics just "mentally" without actually polling the device.

Zabbix 6.4 uses "new method" available starting from the 6.4: https://support.zabbix.com/browse/ZBXNEXT-4428

This new template (for the new installations, for old one - update manually) retrieves metrics using GetBulk() request specified in SNMP standard, if the the device like NEXUS 9000 is overloaded with 100 packets per minute and not compliant with SNMP standard - something is broken on the device side, you need to contact Cisco.

Please be advised that this section of the tracker is for bug reports only. The case you have submitted can not be qualified as one, so please reach out to [email protected] for commercial support (https://zabbix.com/support) or consultancy services. Alternatively, you can also use our IRC channel or community forum (https://www.zabbix.com/forum) for assistance. With that said, we are closing this ticket. Thank you for understanding.

Comment by Smirnov Dmitriy [ 2023 Sep 28 ]

I observed similar behavior in Zabbix 6.0.20. Zabbix overload the APC PDU and the Cisco switch via snmp.
The monitoring metrics did not change, but the number of requests simply increased sharply from two o’clock in the morning.
However, disabling the device from monitoring did not solve the problem. Only restarting the Zabbix server service helped.
So far the problem has not recurred.

On screenshot you can see snmp packets rate on Zabbix 5, which work fine and Zabbix 6 which fails with snmp requsest.

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