The inputs.conf file is the primary configuration file that controls how a Splunk forwarder collects local data.
The Core Control File: inputs.conf
The inputs.conf file is fundamental to the operation of any Splunk forwarder. It dictates precisely what data the forwarder should monitor, where to find this data on the local system, and how it should be processed before being securely sent to a Splunk indexer for storage and analysis. This file is the central point for defining all data ingestion sources for the forwarder.
Understanding Data Collection with inputs.conf
A Splunk forwarder is a lightweight agent designed to collect data from various sources and forward it to a Splunk indexer. Its efficiency and purpose hinge on the accurate configuration within inputs.conf.
This critical configuration file allows administrators to specify a wide array of data inputs, ensuring that relevant machine data is captured and made available for security monitoring, operational intelligence, and compliance.
Common Types of Data Inputs Configured in inputs.conf
inputs.conf supports diverse methods for data collection, accommodating virtually any type of machine data. Here are some of the most common input types:
- File & Directory Monitoring: The most frequent use case involves monitoring specific log files or directories for new events. This is ideal for application logs, server logs, and custom text files.
- Network Data Collection: Forwarders can listen on network ports to collect data via TCP or UDP. This is commonly used for syslog data, NetFlow, or other network-based events.
- Scripted Inputs: For highly customized data sources or when data needs to be pre-processed or generated programmatically,
inputs.confcan execute scripts at specified intervals. - Windows Event Logs: On Windows systems,
inputs.confenables the collection of various Windows Event Log channels (e.g., Application, System, Security) and specific event codes. - Performance Monitoring: Forwarders can collect performance metrics from the operating system or specific applications, providing insights into resource utilization.
Key Stanzas and Examples in inputs.conf
Within inputs.conf, data inputs are defined using stanzas, which are sections enclosed in square brackets []. Each stanza defines a specific input type and its parameters.
| Stanza Type | Purpose | Example Parameters (Conceptual) |
|---|---|---|
[monitor] |
Monitors files and directories for changes. | path = /var/log/myapp/*.log, sourcetype = myapp_logs |
[script] |
Executes a script to generate data. | interval = 300, script = /opt/splunk/bin/my_data_script.sh |
[tcp] |
Listens on a TCP port for network data. | listenPort = 514, sourcetype = syslog |
[udp] |
Listens on a UDP port for network data. | listenPort = 514, sourcetype = syslog |
[winmonitor] |
Monitors specific files on Windows. | path = C:\Program Files\App\Logs\*.txt |
[wineventlog] |
Collects Windows Event Log data. | start_from = oldest, evt_dns_resolve_enabled = 0, current_only = 0 |
[splunktcp] |
Receives data from other Splunk forwarders. | listenPort = 9997 |
Note: The examples above are simplified and for illustrative purposes. Real-world configurations may include additional parameters for indexing, host naming, and data filtering.
Best Practices for Configuring inputs.conf
To ensure efficient and reliable data collection, consider these best practices:
- Location: While
inputs.confcan reside in the default$SPLUNK_HOME/etc/system/defaultdirectory, it's best practice to place your custom configurations in$SPLUNK_HOME/etc/system/localor within a specific Splunk application directory (e.g.,$SPLUNK_HOME/etc/apps/my_app/local) to manage changes easily and prevent conflicts during upgrades. - Source Type Definition: Always specify an appropriate
sourcetypefor each input. This is crucial for Splunk to correctly parse and categorize your data. - Index Assignment: Directing data to specific indexes using the
indexparameter helps organize your data and improves search performance. - Host Field Configuration: Ensure the
hostfield accurately reflects the data's origin. This can be set explicitly or derived automatically. - Monitoring vs. One-shot: Understand the difference between
[monitor](for continuous monitoring of file changes) and[oneshot](for ingesting a file once). - Permissions: Ensure the Splunk user account has the necessary file system permissions to read the data sources defined in
inputs.conf.
By effectively configuring inputs.conf, organizations can ensure that all critical machine data is efficiently collected by the forwarder and made available for comprehensive analysis within the Splunk platform. For more detailed information on configuring the universal forwarder, refer to the official Splunk documentation on configuring the universal forwarder.
