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Apache web server 🔗

Description 🔗

The Splunk OpenTelemetry Collector provides this integration as the Apache web server monitor with the SignalFx Smart Agent receiver. The integration monitors Apache web servers using information mod_status provides.

To see the monitor source, view the signalfx-agent project on GitHub.

Apache worker threads can be in one of the following states:

State Remark
Open Open (unused) slot - no process
Waiting Idle and waiting for request
Sending Serving response
KeepAlive Kept alive for possible next request
Idle_cleanup Idle and marked for cleanup
Closing Closing connection
Logging Writing to log file
Reading Reading request
Finishing Finishing as part of graceful shutdown
Starting Starting up to serve

Installation 🔗

Note: Providing an Apache web server monitor entry in your Smart Agent or Collector configuration is required for its use. Use the appropriate form for your agent type.

This monitor is available in the SignalFx Smart Agent Receiver, which is part of the Splunk Distribution of OpenTelemetry Collector.

Follow these steps to deploy the integration:

  1. Deploy the Splunk OpenTelemetry Collector to your host or container platform.

  2. Complete the Splunk OpenTelemetry Collector configuration.

  3. Complete the Apache configuration.

Splunk OpenTelemetry Collector configuration 🔗

The Splunk Distribution of OpenTelemetry Collector allows embedding a Smart Agent monitor configuration in an associated Smart Agent Receiver instance.

After you deploy the Splunk OpenTelemetry Collector, follow these steps to activate the monitor in the Splunk OpenTelemetry Collector:

  1. Add the following monitor to your agent configuration:

    monitors:  # All monitor config goes under this key
     - type: collectd/apache
       ...  # Additional config
  2. Restart the Splunk OpenTelemetry Collector.

See configuration examples for specific use cases that show how the collector can integrate and complement existing environments.

The following configuration options are available for this monitor:

Options Required Type Description
host yes string The hostname of the Apache server
port yes integer The port number of the Apache server
name no string This will be sent as the plugin_instance dimension and can be any name you like.
url no string The URL, either a final URL or a Go template that will be populated with the host and port values. (default: http://{{.Host}}:{{.Port}}/mod_status?auto)
username no string
password no string

Apache configuration 🔗

After you deploy the monitor in the Splunk OpenTelemetry Collector, follow these steps to configure the Apache web server to expose status metrics:

  1. Enable the mod_status module in your Apache server. Make sure that the URL you provide for your mod_status module ends in ?auto. This returns the status page as text/plain, which the monitor requires.

  2. Add the following configuration to your Apache server:

     ExtendedStatus on
     <Location /mod_status>
     SetHandler server-status
  3. Restart the Apache web server.

Metrics 🔗

These metrics are available for this integration.


Metrics that are categorized as container/host (default) are in bold and italics in the list below.

  • apache_bytes (cumulative)
    Amount of data served by Apache, in bytes.

  • apache_connections (gauge)
    The number of connections that are being served by Apache. This is also equal to the number of busy worker threads, where ‘busy’ means any worker thread which has been started successfully and is not slated for idle cleanup.

  • apache_idle_workers (gauge)
    The number of Apache workers that are idling. If this number is consistently low, then your server may be too busy and you may have to increase the number of threads. If it is consistently high, then the system may be under-utilized.

  • apache_requests (cumulative)
    The number of requests that have been served by Apache. This metric is useful to know total requests and the rate at which Apache is able to serve them.

  • apache_scoreboard.closing (gauge)
    This metric shows how many worker threads are in the process of closing TCP connections after serving a response. If this number is consistently high, then there might be a network issue or errant client preventing TCP tear-down.

  • apache_scoreboard.dnslookup (gauge)
    This metric counts the number of worker threads that are performing a DNS lookup. If this number is too high, check if there is a DNS resolution problem at your server. This can affect Apache server performance.

  • apache_scoreboard.finishing (gauge)
    The number of worker threads that are finishing as part of graceful server shutdown.

  • apache_scoreboard.idle_cleanup (gauge)
    The number of worker threads that are idle and ready for clean-up.

  • apache_scoreboard.keepalive (gauge)
    The number of worker threads that are maintaining keep-alive connections: keeping the connection “alive” after serving a response, in the expectation that another HTTP request will come on the same connection. At the end of the keep-alive interval, the connection is closed.

  • apache_scoreboard.logging (gauge)
    This metric shows how many worker threads are busy writing to the log file. If this number is consistently high, your logging level may be too high or one or more modules may be too verbose.

  • (gauge)
    This metric shows how many worker slots are open. The slots do not have a worker thread yet, but they can be spun up based on incoming requests.

  • apache_scoreboard.reading (gauge)
    This metric shows how many workers are in the process of receiving requests (headers or body). If this number is consistently high, clients may be sending large headers or uploading large files.

  • apache_scoreboard.sending (gauge)
    This metric shows how many workers are sending responses. It is normal for this to be a large number when measuring sites that serve large downloads.

  • apache_scoreboard.starting (gauge)
    This metric shows how many workers are being started up. If this number is consistently high, then the system may be overloaded.

  • apache_scoreboard.waiting (gauge)
    This metric shows how many worker threads are ready and waiting for requests to come in.

Non-default metrics (version 4.7.0+) 🔗

To emit metrics that are not default, you can add those metrics in the generic monitor-level extraMetrics config option. Metrics that are derived from specific configuration options that do not appear in the above list of metrics do not need to be added to extraMetrics.

To see a list of metrics that will be emitted you can run agent-status monitors after configuring this monitor in a running agent instance.

Dimensions 🔗

The following dimensions may occur on metrics emitted by this monitor. Some dimensions may be specific to certain metrics.

Name Description
plugin_instance Set to whatever you set in the name config option.