Getting Data In

Change hostname for syslog sourcetype ?

frankejj
Explorer

Hi,

I am trying to override the default hostname that is being set for the syslog entries on /var/log/messages. These are the only entries that are being indexed with 'hostname' instead of 'hostname.fqdn'

I have tried the following:
   $SPLUNKHOME/etc/system/local/props.conf:
      [syslog]
      TRANSFORMS =

RESULT: No difference

   $SPLUNKHOME/etc/system/local/props.conf:
     [source::/var/log/messages]
     # note: overriding default syslog transform!
     TRANSFORMS = something

   $SPLUNKHOME/etc/system/local/transforms.conf
     [something]
     DEST_KEY = MetaData:Host
     REGEX = .
     FORMAT = host::hostname.fqdn

RESULT: No difference

Am I missing something?

Thanks, John

0 Karma
1 Solution

Lowell
Super Champion

You realize that once the events are indexed they will not be changed by any configuration change. You will have to restart, and then only newly loaded events will have any change.

Otherwise, it looks like what you are trying should work.

Update:

The one thing I'm not sure about is exactly how the TRANSFORMS is being overwritten. The default config for syslog, which I'm assuming it the sourcetype you are using, uses the "syslog-host" transformer to extract the "host" value from the event text. Of the top of my head, I'm not sure which setting should win in a source vs sourcetype matching precedent like this (normally I try to avoid this kind of conflict.) Using btool and splunk test sourcetype /var/log/messages could be shed some light on the situation.


Related answers:

View solution in original post

0 Karma

Lowell
Super Champion

You realize that once the events are indexed they will not be changed by any configuration change. You will have to restart, and then only newly loaded events will have any change.

Otherwise, it looks like what you are trying should work.

Update:

The one thing I'm not sure about is exactly how the TRANSFORMS is being overwritten. The default config for syslog, which I'm assuming it the sourcetype you are using, uses the "syslog-host" transformer to extract the "host" value from the event text. Of the top of my head, I'm not sure which setting should win in a source vs sourcetype matching precedent like this (normally I try to avoid this kind of conflict.) Using btool and splunk test sourcetype /var/log/messages could be shed some light on the situation.


Related answers:

0 Karma

frankejj
Explorer

Thanks for the answer - using the related questions helped a lot. Also key piece of info was that SplunkLightForwarders do not apply transforms. The transforms get applied on the indexer.

0 Karma

frankejj
Explorer

Yes, I realize this. Even after the changes above the new syslog entries are still being indexed as hostname not as hostname.fqdn as I would expect.

0 Karma
Got questions? Get answers!

Join the Splunk Community Slack to learn, troubleshoot, and make connections with fellow Splunk practitioners in real time!

Meet up IRL or virtually!

Join Splunk User Groups to connect and learn in-person by region or remotely by topic or industry.

Get Updates on the Splunk Community!

Agent Mode Engaged! Enchaining Agentic Operations with Splunk AI Assistant 2.0

    Are you ready to transform how your team handles complex data requests? We invite you to our upcoming ...

Announcing Modern Navigation: A New Era of Splunk User Experience

We are excited to introduce the Modern Navigation feature in the Splunk Platform, available to both cloud and ...

Modernize your Splunk Apps – Introducing Python 3.13 in Splunk

We are excited to announce that the upcoming releases of Splunk Enterprise 10.2.x and Splunk Cloud Platform ...