Metric plugins - mackerel-plugin-apache2
mackerel-plugin-apache2 provides a way to monitor statistics about Apache2 as a metric.
To use this plugin, the Apache Status module (mod_status) must be enabled and accessible from the plugin.
Monitorable metrics
The metrics that can be monitored by mackerel-plugin-apache2 are as follows.
Apache Workers
The number of running server processes and threads can be monitored.
| Metric Display Name | Metric Name | Diff | Stacked | Description |
|---|---|---|---|---|
| Busy Workers | custom.apache2.workers.busy_workers | ✓ | The number of busy worker requests/threads | |
| Idle Workers | custom.apache2.workers.idle_workers | ✓ | The number of idle worker requests/threads |
Apache Bytes
The amount of data sent out by the httpd process can be monitored.
| Metric Display Name | Metric Name | Diff | Stacked | Description |
|---|---|---|---|---|
| Bytes Sent | custom.apache2.bytes.bytes_sent | ✓ | Total traffic bytes per minute |
Apache CPU Load
CPU utilization of the httpd process can be monitored.
| Metric Display Name | Metric Name | Diff | Stacked | Description |
|---|---|---|---|---|
| CPU Load | custom.apache2.cpu.cpu_load | CPU utilization |
Apache Requests
The number of requests can be monitored.
| Metric Display Name | Metric Name | Diff | Stacked | Description |
|---|---|---|---|---|
| Requests | custom.apache2.req.requests | ✓ | The number of requests received per minute |
Apache Scoreboard
Each metric on the scoreboard (state of running server processes) can be monitored.
| Metric Display Name | Metric Name | Diff | Stacked | Description |
|---|---|---|---|---|
| Waiting for connection | custom.apache2.scoreboard.score-_ | ✓ | The number of processes/threads started and waiting to be accessed | |
| Starting up | custom.apache2.scoreboard.score-S | ✓ | The number of processes/threads running | |
| Reading request | custom.apache2.scoreboard.score-R | ✓ | The number of client requests being read | |
| Sending reply | custom.apache2.scoreboard.score-W | ✓ | The number of responses to clients | |
| Keepalive | custom.apache2.scoreboard.score-K | ✓ | The number of requests waiting for KeepAlive | |
| DNS lookup | custom.apache2.scoreboard.score-D | ✓ | The number of names resolved by DNS | |
| Closing connection | custom.apache2.scoreboard.score-C | ✓ | The number of connections closed | |
| Logging | custom.apache2.scoreboard.score-L | ✓ | The number of logs output | |
| Gracefully finishing | custom.apache2.scoreboard.score-G | ✓ | The number of cases waiting for the end of processing in graceful restart | |
| Idle cleanup | custom.apache2.scoreboard.score-I | ✓ | The number of processes/threads stopped | |
| Open slot | custom.apache2.scoreboard.score- | ✓ | The number of slots available |
Configurable options
The options which can be configured in the plugin are as follows.
| Option | Short | Environment Variables | Description | Default |
|---|---|---|---|---|
| --http_host | -o | IP address being listened to by httpd | 127.0.0.1 | |
| --http_port | -p | Port number being listened to by httpd | 80 | |
| --header | -H | HTTP header to be given at the time of request from plugin | ||
| --status_page | -s | URL path where statistics are available | /server-status?auto | |
| --tempfile | -t | MACKEREL_PLUGIN_WORKDIR | Destination path for temporary file | |
| --metric-key-prefix | String to be given as prefix to the metric name | apache2 | ||
| --metric-label-prefix | String to be assigned to the graph name as prefix | Apache |
- Temporary files are created by default under
/var/tmp/mackerel-agentor/tmpin the formatmackerel-plugin-{Prefix or other string}-{hash string}.
Example configuration
[plugin.metrics.apache2]
command = ["mackerel-plugin-apache2", "-p", "1080"]To check the above settings manually, you can execute the following at the terminal.
mackerel-plugin-apache2 -p 1080Configuration for Apache
Make sure that the Apache Status module (mod_status) is enabled in order to use mackerel-plugin-apache2.
The following configuration assumes publication at http://127.0.0.1:1080/server-status.
ExtendedStatus On
<VirtualHost 127.0.0.1:1080>
<Location /server-status>
SetHandler server-status
Order deny,allow
Deny from all
Allow from localhost
</Location>
</VirtualHost>Troubleshooting
Cannot get metrics
If you are unable to obtain a metric after setting up the plugin, it may be due to a configuration that has not been reflected or an incorrect setting of the Status module on the Apache side. Please check the following points.
- Whether or not mackerel-agent has been restarted after the plugin has been configured.
- Restarting mackerel-agent is required for the settings to take effect.
- Can you connect to the server-status endpoint with the curl command?
Please confirm that you can receive the HTTP 200 OK response with the following command when configured as shown in the configuration example.
curl http://127.0.0.1:1080/server-statusIf you have a
httptohttpsredirect configured in mod_rewrite, the plugin will not track the redirect; the Status module endpoint should be excluded from the redirect.If you cannot get the results of the Status module with the curl command, it may be because it has been incorrectly configured or Apache has not been restarted.
Repository
https://github.com/mackerelio/mackerel-agent-plugins/tree/master/mackerel-plugin-apache2