I've read the other questions/answers on this issue but I need some further assistance please?
Can someone please advice which index I need to change to remove the reference to [splunklogger] as I'm having a difficult time finding the right index to edit.
I had this problem with my forwarders when copying deployments from a 4.1.3 instance to a 4.1.4 instance.
I ended up modifying the inputs.conf & indexes.conf to delete the references to splunklogger..
During the first start up after the upgrade, Splunk tries to validate the existence of all declared indexes in the indexes.conf found in your configuration directories.
Even if an index is disabled with "disabled = true" or by being present in the indexes.conf of a disabled app, Splunk will freak out if it cannot locate it's "homePath" (whether it's the default one in $SPLUNK_DB or a custom one specified in indexes.conf).
The quickest way to troubleshoot this problem is to compare the output of two commands.
The first one displays all existing index configuration stanzas across all indexes.conf :
# find $SPLUNK_HOME/etc/ -name indexes.conf | xargs grep ^\\[
The second command will list the directories present in $SPLUNK_DB ($SPLUNK_HOME/var/lib/splunk/ by default), which is the default "homePath" for each index if no other value for that parameter is specified.
# ls -l $SPLUNK_DB
# ls -l $SPLUNK_HOME/var/lib/splunk/
If the first command shows an index that is not present in $SPLUNK_DB and that index doesn't have a setting for "homePath" that points to an existing directory, you should consider disabling that index stanza in that configuration file by preceding it with a "#".
Typical culprits are "splunklogger" (which has been deprecated and is often present but disabled) and "os" (which is often present in disabled apps like "unix" or "nixLF").
This is particularly effective on a forwarder where there shouldn't be any indexes configured other than what can be found in $SPLUNK_DB.
Here's a typical scenario :
1) Which index directories exist?
# ls -l $SPLUNK_DB total 52 drwx--x--x 5 root root 4096 Jun 25 16:29 audit drwx--x--x 2 root root 4096 Jun 25 10:14 authDb drwx--x--x 5 root root 4096 Jun 25 16:29 blockSignature drwx--x--x 5 root root 4096 Jun 25 16:29 defaultdb drwx--x--x 6 root root 4096 Jun 25 16:29 fishbucket drwx--x--x 2 root root 4096 Jun 25 16:29 hashDb drwx--x--x 5 root root 4096 Jun 25 16:29 historydb drwx--x--x 5 root root 4096 Jun 25 16:29 _internaldb drwx------ 2 root root 4096 Jun 25 16:29 persistentstorage drwx------ 2 root root 4096 Jun 25 16:27 queues drwx--x--x 5 root root 4096 Jun 25 16:29 sample drwx--x--x 5 root root 4096 Jun 25 16:29 splunkloggerdb drwx--x--x 5 root root 4096 Jun 25 16:29 summarydb
2) Which indexes are declared in the configuration files?
# find $SPLUNK_HOME/etc/ -name indexes.conf | xargs grep ^\\[ etc/system/default/indexes.conf:[main] etc/system/default/indexes.conf:[history] etc/system/default/indexes.conf:[summary] etc/system/default/indexes.conf:[_internal] etc/system/default/indexes.conf:[_audit] etc/system/default/indexes.conf:[_thefishbucket] etc/system/default/indexes.conf:[_blocksignature] etc/system/default/indexes.conf:[splunklogger] etc/apps/sample_app/default/indexes.conf:[sample] etc/apps/nixLF/default/indexes.conf:[main] etc/apps/nixLF/default/indexes.conf:[history] etc/apps/nixLF/default/indexes.conf:[summary] etc/apps/nixLF/default/indexes.conf:[_internal] etc/apps/nixLF/default/indexes.conf:[_audit] etc/apps/nixLF/default/indexes.conf:[_blocksignature] etc/apps/nixLF/default/indexes.conf:[splunklogger] etc/apps/unix/default/indexes.conf:[os] etc/apps/SplunkLightForwarder/default/indexes.conf:[main] etc/apps/SplunkLightForwarder/default/indexes.conf:[history] etc/apps/SplunkLightForwarder/default/indexes.conf:[summary] etc/apps/SplunkLightForwarder/default/indexes.conf:[_internal] etc/apps/SplunkLightForwarder/default/indexes.conf:[_audit] etc/apps/SplunkLightForwarder/default/indexes.conf:[_blocksignature] etc/apps/SplunkLightForwarder/default/indexes.conf:[splunklogger]
This revealed the following culprits :
etc/apps/unix/default/indexes.conf:[os] etc/system/default/indexes.conf:[splunklogger] etc/apps/nixLF/default/indexes.conf:[splunklogger] etc/apps/SplunkLightForwarder/default/indexes.conf:[splunklogger]
The "splunklogger" index was disabled everywhere it was declared with "disabled = true", and the "os" index was not in use as the unix app was disabled. Once these stanzas and all of their associated parameters were commented out, the upgrade worked!