I upgraded to 4.1.4 but now I get an error on startup - could not validate indexes - what does this mean?

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

or

# 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!