Apache Web Server (httpd)

The Apache Web Server integration collects traffic-related metrics, such as the number of open connections or incoming requests. The integration also collects access and error logs. Access logs are parsed into a JSON payload focused on request details, and error logs are parsed for their error code and message.

For more information about Apache Web Server, see http://httpd.apache.org/.

Prerequisites

To collect Apache Web Server telemetry, you must install Ops Agent version 2.7.0 or higher.

This receiver supports Apache Web Server version 2.4.

Configure your Apache Web Server instance

To collect telemetry from your Apache Web Server, you must configure the server's httpd.conf file to enable the mod_status plugin.

Many Apache installations enable this plugin by default. To see if the plugin is enabled on your VM instance, run:

curl localhost:80/server-status?auto

If the plugin is enabled, then the output includes lines similar to the following:

Total Accesses: 2
Total kBytes: 1
BusyWorkers: 1
IdleWorkers: 4

If you get a 404 Not Found page instead, then the mod_status plugin is not enabled.

Configure the Ops Agent for Apache Web Server

Following the guide for Configuring the Ops Agent, add the required elements to collect logs from Apache Web Server instances, and restart the agent.

Example configuration

The following command creates the configuration to collect and ingest logs and metrics for Apache Web Server and restarts the Ops Agent on Linux.

sudo tee /etc/google-cloud-ops-agent/config.yaml > /dev/null << EOF
logging:
  receivers:
    apache_access:
      type: apache_access
    apache_error:
      type: apache_error
  service:
    pipelines:
      apache:
        receivers:
        - apache_access
        - apache_error
metrics:
  receivers:
    apache:
      type: apache
  service:
    pipelines:
      apache:
        receivers:
        - apache
EOF
sudo service google-cloud-ops-agent restart

Configure logs collection

To ingest logs from Apache Web Server, you must create receivers for the logs Apache Web Server produces and then create a pipeline for the new receivers. To configure a receiver for your logs, specify the following fields:

To configure a receiver for your apache_access logs, specify the following fields:

Field	Default	Description
`type`		This value must be `apache_access`.
`include_paths`	`[/var/log/apache2/access.log,/var/log/apache2/access_log,/var/log/httpd/access_log]`	A list of filesystem paths to read by tailing each file. A wild card (``) can be used in the paths; for example, `/var/log/apache/*.log`.
`exclude_paths`	`[]`	A list of filesystem path patterns to exclude from the set matched by `include_paths`.
`wildcard_refresh_interval`	`60s`	The interval at which wildcard file paths in `include_paths` are refreshed. Given as a time duration, for example `30s` or `2m`. This property might be useful under high logging throughputs where log files are rotated faster than the default interval.

To configure a receiver for your apache_error logs, specify the following fields:

Field	Default	Description
`type`		This value must be `apache_error`.
`include_paths`	`[/var/log/apache2/error.log,/var/log/apache2/error_log,/var/log/httpd/error_log]`	A list of filesystem paths to read by tailing each file. A wild card (``) can be used in the paths; for example, `/var/log/apache/*.log`.
`exclude_paths`	`[]`	A list of filesystem path patterns to exclude from the set matched by `include_paths`.
`wildcard_refresh_interval`	`60s`	The interval at which wildcard file paths in `include_paths` are refreshed. Given as a time duration, for example `30s`, `2m`. This property might be useful under high logging throughputs where log files are rotated faster than the default interval.

What is logged

The logName of the apache_access and apache_error logs are derived from the receiver IDs specified in the configuration. Detailed fields inside the LogEntry are as follows.

apache_access logs contain the httpRequest field:

Field	Type	Description
`httpRequest.protocol`	string	Protocol used for the request
`httpRequest.referer`	string	Contents of the `Referer` header
`httpRequest.requestMethod`	string	HTTP method
`httpRequest.requestUrl`	string	Request URL (typically just the path part of the URL)
`httpRequest.responseSize`	string (`int64`)	Response size
`httpRequest.status`	number	HTTP status code
`httpRequest.userAgent`	string	Contents of the `User-Agent` header
`jsonPayload.host`	string	Contents of the `Host` header
`jsonPayload.user`	string	Authenticated username for the request
`timestamp`	string (`Timestamp`)	Time the request was received

Log entries don't contain any fields that are blank or missing.

apache_error logs contain the following fields in the LogEntry:

Field	Type	Description
`jsonPayload.errorCode`	string	Apache error code
`jsonPayload.level`	string	Log entry level
`jsonPayload.module`	string	apache module where the log originated
`jsonPayload.pid`	number	Process ID
`jsonPayload.tid`	number	Thread ID
`jsonPayload.message`	string	Log message
`jsonPayload.client`	string	Client IP address (optional)
`severity`	string (`LogSeverity`)	Log entry level (translated)
`timestamp`	string (`Timestamp`)	Time the entry was logged

Configure metrics collection

To collect metrics from Apache Web Server, you must create a receiver for Apache metrics and then create a pipeline for the new receiver. To configure a receiver for your Apache metrics, specify the following fields:

Field	Default	Description
`type`		This value must be `apache`.
`server_status_url`	`http://localhost:80/server-status?auto`	The URL exposed by the `mod_status` module.
`collection_interval`	`60s`	A time.Duration value, such as `30s` or `5m`.

What is monitored

The following table provides the list of metrics that the Ops Agent collects from the Apache Web Server instance.

Metric type
Kind, Type Monitored resources	Labels
`workload.googleapis.com/apache.current_connections`
`GAUGE`, `INT64` gce_instance	`server_name`
`workload.googleapis.com/apache.requests`
`CUMULATIVE`, `INT64` gce_instance	`server_name`
`workload.googleapis.com/apache.scoreboard`
`GAUGE`, `INT64` gce_instance	`state` `server_name`
`workload.googleapis.com/apache.traffic`
`CUMULATIVE`, `INT64` gce_instance	`server_name`
`workload.googleapis.com/apache.workers`
`GAUGE`, `INT64` gce_instance	`state` `server_name`

Sample dashboard

You can view the metrics from this integration using a sample Cloud Monitoring dashboard. Complete the Installing sample dashboards procedures to import the Apache GCE Overview dashboard from the Sample library and view charts that display your Apache Web Server metrics.

Verify the configuration

You can use the Logs Explorer and Metrics Explorer to verify that you correctly configured the Apache Web Server receiver. It might take one or two minutes for the Ops Agent to begin collecting logs and metrics.

To verify the logs are ingested, go to the Logs Explorer and run the following query to view the Apache Web Server logs:

resource.type="gce_instance"
logName=("projects/PROJECT_ID/logs/apache_access" OR "projects/PROJECT_ID/logs/apache_error")

To verify the metrics are ingested, go to Metrics Explorer and run the following query in the MQL tab.

fetch gce_instance
| metric 'workload.googleapis.com/apache.requests'
| align rate(1m)
| every 1m

What's next

For a walkthrough on how to use Ansible to install the Ops Agent, configure a third-party application, and install a sample dashboard, see the Install the Ops Agent to troubleshoot third-party applications video.