topic Re: Rewrite hostname don't work in Getting Data In

Rewrite hostname don't work

bizza — Mon, 28 Sep 2020 09:59:14 GMT

Hi all,
I need to append the domain to all hosts that send data to my splunk indexer, to avoid duplications (hostname and hostname.domain are the same host)

This is my transforms.conf

[syslog_add_fqdn]
REGEX=host::([A-Za-z][-_A-Za-z0-9]*[A-Za-z0-9])$
FORMAT=host::$1.domain.local
WRITE_META=true
DEST_KEY=MetaData:Host
SOURCE_KEY=MetaData:Host

and props.conf

[linux_secure]
TRANSFORMS-zz_fix_host = syslog_add_fqdn

[syslog]
TRANSFORMS-zz_fix_host = syslog_add_fqdn

In $SPLUNK_HOME/var/log/splunk/splunkd.log I found this error:

/opt/splunk/var/log/splunk/splunkd.log:10-14-2011 13:22:58.652 +0200 ERROR regexExtractionProcessor - DEST_KEY or WRITE_META=true must be specified tranform_name=syslog_add_fqdn

What is wrong?
I tried to remove WRITE_META from my rules, change its position, but my indexer still log hostname on syslog souce type and hostname.domain on linux_secure source type (because on it my system log fqdn, the rule don't work).

Any hints?

Re: Rewrite hostname don't work

_d_ — Fri, 14 Oct 2011 16:10:26 GMT

I would start troubleshooting the problem by removing the host:: from the REGEX= line:
The SOURCE_KEY=MetaData:Host makes the REGEX operator work only on the host fied.

Re: Rewrite hostname don't work

Paolo_Prigione — Sat, 15 Oct 2011 11:07:34 GMT

You might have a conflict with the [syslog-host] rule in $SPLUNK_HOME/etc/system/default/transforms.conf, which is called by props.conf as:

[syslog]
....
TRANSFORMS = syslog-host

Maybe your rule is evaluated first, but then its results are overwritten by the default one.
You could try to force an order as:

[syslog]
...
TRANSFORMS = 
TRANSFORMS-zz_fix_host = syslog-host, syslog_add_fqdn

Have you inspected your runtime configurations with btool?

splunk btool --debug props list

Other than that, I recall the "-" when used in character classes should be either escaped or at the end of the class itself, otherwise it means a range.

[syslog_add_fqdn]
REGEX = host::([A-Za-z][\w\-]*[A-Za-z0-9])$
FORMAT = host::$1.domain.local
DEST_KEY = MetaData:Host
SOURCE_KEY = MetaData:Host

The write_meta should not be necessary in this case.

Re: Rewrite hostname don't work

bizza — Tue, 18 Oct 2011 18:32:15 GMT

I'll check asap
Grazie Paolo 🙂