Modular Inputs That Don’t Make a Mess

When I started building forwarder configurations for more than a handful of servers, I realized the default approach—stuffing inputs.conf into system/local—doesn’t scale. You get drift, conflicts, and no clear way to track ownership.

This post covers how we started modularizing inputs early in our Splunk journey, well before we had full deployment server automation. The goal was simple: isolate, name, and deploy clean inputs that didn’t overlap or clobber each other.

Why system/local Shouldn’t Be Default

Putting all your configs in system/local is fine until someone else needs to touch it. Or until you have to roll back. Or explain why three apps are all monitoring the same folder differently.

If you're working in a shared environment, or one that might be audited or scaled, local configs become technical debt quickly.

App-Level Inputs

We moved toward app-scoped inputs by creating one app per logical set of sources. For example:

• TA_win_evtlogs
• TA_linux_syslog
• TA_iis_logs

Each of these had its own directory structure and lived in $SPLUNK_HOME/etc/apps/.

Within each, only relevant files existed. No copied default files. No globals unless required.

plaintext TA_win_evtlogs/ ├── default/ │ └── inputs.conf TA_linux_syslog/ ├── default/ │ └── inputs.conf

This let us:

• Know what team owned each input
• Quickly disable or reassign an app without editing shared files
• Make deployment atomic and testable

Input Naming Discipline

We also adopted a standard for input stanza formatting:

ini [monitor:///var/log/httpd/access.log] disabled = false index = web_logs sourcetype = apache_access

Inputs were never generic (monitor:///logs/*) unless we were prepared for wildcard ingestion and the mess that comes with it. Explicit is safer.

Lessons Learned

• Build modular apps even before DS is enforced
• Every input should have a documented owner
• Avoid overlap—both in path coverage and stanza naming
• Use app naming to reflect purpose, not just project code names

---

This setup helped us transition smoothly to deployment server later—and made migrations, audits, and triage a lot faster.

If you’re just starting out with more than a dozen forwarders, don’t wait. Clean it up now. Future you will thank you.