SNMP Monitoring on CentOS 8 with Zabbix 5.4.8.1 - SNMP always Greyed Out

[mvk]

Hi, I hope I am not creating a duplicate but so far I could not see a solution for this issue on Centos8

I have installed (not built) Zabbix 5.4.8.1 onto CentOS 8 and cannot get SNMP monitoring to work. Under the Availability Column , SNMP is greyed out for hosts that I have manually added with SNMP check and for those that have been found via discovery (Where I have added SNMPv1 as a check), there is no SNMP against it.

- When running a tcpdump, I do not see any snmp queries going out at all, whether during discovery or during a manual host add
- I can snmpwalk the target hosts without any issues
- There are no errors in the logs
- sudo is setup to allow all commands (nmap is being executed correctly when I select "Discover Operating System")
- The following snmp libs are installed
-- net-snmp-utils-5.8-22.el8.x86_64
--net-snmp-5.8-22.el8.x86_64
--net-snmp-perl-5.8-22.el8.x86_64
--net-snmp-libs-5.8-22.el8.x86_64
--net-snmp-agent-libs-5.8-22.el8.x86_64


The one here in red was added manually but no snmp query is made to the target ip.




Here is my discovery rule - It seems that nothing other than icmp is matching, even though other hosts are snmp enabled.


A feel a bit stuck as I have followed all install tips that I can find.

cheers

Mark

[ISiroshtan]

If you open Configuration - Hosts - click Items of problem host, there should be an error indicator in Info column. If you mouseover the error icon, it can give some more info into failure reason.

Could you check if you have it?

[mvk]

Hi, I have no error icon and any indication of a failure. it just seems like it is not even attempting to perform any snmp actions

[mvk]

I have no installed the Centos 8 based appliance and the issues are 100% the same. Maybe I need to start reading deeper again. I simply cannot get any SNMP activity to trigger.

Also, strangely I can discover ssh hosts and assign them to a host group but not for http or https.

All clean logs, no errors anywhere

[tim.mooney]

Have you read the documentation for your version on how "availability" is calculated?

https://www.zabbix.com/documentation/current/en/manual/web_interface/frontend_sections/configuration/hosts#reading-host-availability

in particular the "Unknown interface status" section?

Your first post showed a graphic of a list of hosts that had presumably been discovered; the default interface on all of the hosts is the agent interface (not SNMP). Is that your intent?

You didn't show the full host view for any of the hosts (that I can see; apologies if I'm wrong and you did include it, viewing graphics from this forum doesn't work very well with latest Firefox browser), so I can't tell if any of the hosts even have an SNMP interface defined. For one of the discovered hosts that you would like Zabbix to poll via SNMP, does the host have an SNMP interface defined within Zabbix?

[mvk]

Hi Tim, are you referring to this config item ? Interface as added as v1 with a community string

No matter what I do, I don't see any SNMP queries (when using tcpdump) heading for the target IP

[tim.mooney]

I was indeed referring to that view. I wanted to make sure you actually had a SNMP interface defined, and you do.

So your discovery process is finding hosts, and it's defining an agent interface (the default) and an SNMP interface.

That much just defines a host and a couple of ways to query it, but it doesn't actually tell Zabbix to poll it. For that, you would typically have the discovery process assign templates (which contain items, some triggers, possibly graphs etc.) to each discovered host.

So, what templates is the discovery process assigning to the host? From the view you show above (the "Host->Host" view), it's just the next tab over (Host->Templates).

[mvk]

ahah , I got it now. I did not realize that the polling would not start without a template applied

thanks a lot for the help :-)

[tim.mooney]

You're welcome!

Some sites just use discovery to create the hosts, and then manually assign templates to the hosts (and move the hosts to different groups, etc.). If you have lots of different types of network gear, it can sometimes be complicated to get your discovery rules to detect the gear to a granular enough level so that you can decide which template to apply. In those cases, applying no template automatically is an easier thing. Zabbix is flexible, so you can decide how much or how little you want to do with discovery, if you even choose to use discovery. For small sites, especially sites that don't frequently add or remove hosts that need to be monitored, discovery may be overkill.

Polling (at least when you're talking about SNMP polling) starts once at least one SNMP item is defined for the host. Templates are just a great way to bundle collections of items, triggers, and sometimes other stuff together. If you only want to gather a couple of items per host, you don't need to use a template; you can just create the items directly, or clone items from one host to another. Templates are just much more scalable, convenient way of grouping common things together.