# Query Separate Pipeline for Logstash SNMP Input Hosts

**URL:** <https://discuss.elastic.co/t/query-separate-pipeline-for-logstash-snmp-input-hosts/299355>\
**Category:** Logstash\
**Created:** [March 10, 2022, 4:21pm UTC](https://discuss.elastic.co/t/query-separate-pipeline-for-logstash-snmp-input-hosts/299355 "2022-03-10T16:21:15Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![bennrtc](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bennrtc](https://discuss.elastic.co/u/bennrtc)\
**Post date:** [March 10, 2022, 4:21pm UTC](https://discuss.elastic.co/t/query-separate-pipeline-for-logstash-snmp-input-hosts/299355/1 "2022-03-10T16:21:15Z")

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Hello!  
I'm using the Logstash SNMP Input to query a large number of hosts (\> 5,000). The list of host ip addresses changes frequently and requires us to regularly add and remove hosts to ensure our pipeline output is up-to-date. The snmp version and community is the same for all hosts.

A separate pipeline ('ip-addresses-pipeline') produces all of these dynamic ip addresses in a field called [ip-host].

In the SNMP input section of a separate Logstash pipeline, is it possible to query [ip-host] of 'ip-addresses-pipeline' for the regularly updated list of hosts to poll? Is this all possible using an environment variable or the Elasticsearch input (or something else)?

Thank you!

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**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [March 10, 2022, 4:29pm UTC](https://discuss.elastic.co/t/query-separate-pipeline-for-logstash-snmp-input-hosts/299355/2 "2022-03-10T16:29:27Z")

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The snmp input converts the hosts option into an array of client\_definitions as part of its [register](https://github.com/logstash-plugins/logstash-input-snmp/blob/b0f827623cc5e7c3ba2733622fb9484947da6065/lib/logstash/inputs/snmp.rb#L130) function. That is called once when the pipeline is started.

You could run a logstash instance with `--config.reload.automatic` and re-write the configuration file that contains the snmp input configuration. logstash would then reload the pipeline when it notices the configuration has changed.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [April 7, 2022, 4:29pm UTC](https://discuss.elastic.co/t/query-separate-pipeline-for-logstash-snmp-input-hosts/299355/3 "2022-04-07T16:29:45Z")

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