Subnet handling within SNMP input configuration

[szabogergo]

Hi all,

Is it possible somehow to provide subnet handling within hosts attribute (for example defining /prefix or wildcard)? I would like perform SNMP get operation for many hundred of hosts and it would be fine if there was a native tool or solution defining a subnet for given hosts instead of configuring many lines with each host.
Logstash has also a CIDR plugin, but I don't know if it would be usable in this case.

Thanks in advance.

[colinsurprenant]

Thanks for your suggestion @szabogergo! The hosts option is definitely not very usable for large number of hosts.

• Would an external file containing a list of hosts be an alternative viable solution in your case?
• One problem I see with specifying a subnet is how to handle IPs where there is no SNMP host? should we perform the poll on every IPs in the subnet and just report timeouts on each poll cycle or maybe auto-mute those where the is no connection or something around this idea?

[szabogergo]

First, thank you for suggestions.
I agree with you, host option is not the best solution for this purpose, but I can't find any other yet.

The idea of external file containing target IPs is a simple and fast solution if you can extend Logstash SNMP Input configuration with it. I also agree, that subnet containing many (or only a few) unused IP addresses may produce increasing amount of host queries with connection timeout, I don't know what kind of affect may it have regarding Logstash performance but in case of deceleration it shouldn't be usable.

So, I think the external file option with target host list would be preferred in this case.

[luminous706]

Great idea, we poll hundreds of hosts on the network, these hosts are added and removed everyday, we have a network discovery software that discovers live hosts and produces a node list. Would be great for Logstash SNMP input to be able to refer to that list for each poll - as the node list is dynamic.

At the moment, we use a Bash script with printf statements to generate the Logstash configuration file dynamically with the hosts added, every hour.