nginx

The nginx integration collects connection metrics and access logs. Connection metrics capture the current state of the connection: active, reading, or waiting. Access logs are parsed for their connection details, which include fields mapped to request, client, server, and message.

For more information about nginx, see the nginx documentation.

Prerequisites

To collect nginx telemetry, you must install the Ops Agent:

For metrics, install version 2.1.0 or higher.
For logs, install version 2.1.0 or higher.

This integration supports nginx versions 1.18 and 1.20.

Configure your nginx instance

You must enable the stub_status module in the nginx configuration file to set up a locally reachable URL, for example, http://www.example.com/nginx_status for the status page. To enable the stub_status module, complete the following steps:

Edit the status.conf file, or create the file if it doesn't exist. You can find this file in the nginx configuration directory, typically found at /etc/nginx/conf.d.

Add the following lines to the server section:

location /nginx_status {
    stub_status on;
    access_log off;
    allow 127.0.0.1;
    deny all;
}

Your configuration file might look like the following example:

server {
   listen 80;
   server_name 127.0.0.1;
   location /nginx_status {
       stub_status on;
       access_log off;
       allow 127.0.0.1;
       deny all;
   }
   location / {
       root /dev/null;
   }
}

Reload the nginx configuration.
```
sudo service nginx reload
```

You can run the following command to automate the previous steps. It creates a status.conf file if it doesn't exist or overwrites the existing one if it does exist. The command turns on stub_status, reloads nginx, and verifies that the expected information is exposed through the endpoint.

sudo tee /etc/nginx/conf.d/status.conf > /dev/null << EOF
server {
    listen 80;
    server_name 127.0.0.1;
    location /nginx_status {
        stub_status on;
        access_log off;
        allow 127.0.0.1;
        deny all;
    }
    location / {
       root /dev/null;
    }
}
EOF
sudo service nginx reload
curl http://127.0.0.1:80/nginx_status

The sample output is:

Active connections: 1
server accepts handled requests
 23 23 74
Reading: 0 Writing: 1 Waiting: 0

Alternately, instead of using a separate status.conf file, you can also directly embed the lines to the main nginx.conf file, which is typically located in one of the following directories: /etc/nginx, /usr/local/nginx/conf, or /usr/local/etc/nginx.

Configure the Ops Agent for nginx

Following the guide for Configuring the Ops Agent, add the required elements to collect telemetry from nginx instances, and restart the agent.

Example configuration

The following commands create the configuration to collect and ingest telemetry for nginx and restarts the Ops Agent.

# Configures Ops Agent to collect telemetry from the app and restart Ops Agent.

set -e

# Create a back up of the existing file so existing configurations are not lost.
sudo cp /etc/google-cloud-ops-agent/config.yaml /etc/google-cloud-ops-agent/config.yaml.bak

# Configure the Ops Agent.
sudo tee /etc/google-cloud-ops-agent/config.yaml > /dev/null << EOF
metrics:
  receivers:
    nginx:
      type: nginx
      stub_status_url: http://127.0.0.1:80/nginx_status
  service:
    pipelines:
      nginx:
        receivers:
          - nginx
logging:
  receivers:
    nginx_access:
      type: nginx_access
    nginx_error:
      type: nginx_error
  service:
    pipelines:
      nginx:
        receivers:
          - nginx_access
          - nginx_error
EOF

sudo service google-cloud-ops-agent restart
sleep 60

Configure logs collection

To ingest logs from nginx, you must create receivers for the logs that nginx produces and then create a pipeline for the new receivers.

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

Field	Default	Description
`exclude_paths`		A list of filesystem path patterns to exclude from the set matched by `include_paths`.
`include_paths`	`[/var/log/nginx/access.log]`	A list of filesystem paths to read by tailing each file. A wild card (`*`) can be used in the paths.
`record_log_file_path`	`false`	If set to `true`, then the path to the specific file from which the log record was obtained appears in the output log entry as the value of the `agent.googleapis.com/log_file_path` label. When using a wildcard, only the path of the file from which the record was obtained is recorded.
`type`		The value must be `nginx_access`.
`wildcard_refresh_interval`	`60s`	The interval at which wildcard file paths in include_paths are refreshed. Given as a time duration parsable by `time.ParseDuration`, 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 nginx_error logs, specify the following fields:

Field	Default	Description
`exclude_paths`		A list of filesystem path patterns to exclude from the set matched by `include_paths`.
`include_paths`	`[/var/log/nginx/error.log]`	A list of filesystem paths to read by tailing each file. A wild card (`*`) can be used in the paths.
`record_log_file_path`	`false`	If set to `true`, then the path to the specific file from which the log record was obtained appears in the output log entry as the value of the `agent.googleapis.com/log_file_path` label. When using a wildcard, only the path of the file from which the record was obtained is recorded.
`type`		The value must be `nginx_error`.
`wildcard_refresh_interval`	`60s`	The interval at which wildcard file paths in include_paths are refreshed. Given as a time duration parsable by `time.ParseDuration`, for example `30s` or `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 is derived from the receiver IDs specified in the configuration. Detailed fields inside the LogEntry are as follows.

The nginx_access logs contain the following fields in the LogEntry:

Field	Type	Description
`httpRequest`	object	See `HttpRequest`
`jsonPayload.host`	string	Contents of the Host header (usually not reported by nginx)
`jsonPayload.level`	string	Log entry level
`jsonPayload.user`	string	Authenticated username for the request
`severity`	string (`LogSeverity`)	Log entry level (translated).

The nginx_error logs contain the following fields in the LogEntry:

Field	Type	Description
`jsonPayload.client`	string	Client IP address (optional)
`jsonPayload.connection`	number	Connection ID
`jsonPayload.host`	string	Host header (optional)
`jsonPayload.level`	string	Log entry level
`jsonPayload.message`	string	Log message
`jsonPayload.pid`	number	The process ID issuing the log
`jsonPayload.referer`	string	Referer header (optional)
`jsonPayload.request`	string	Original HTTP request (optional)
`jsonPayload.server`	string	Nginx server name (optional)
`jsonPayload.subrequest`	string	Nginx subrequest (optional)
`jsonPayload.tid`	number	Thread ID where the log originated
`jsonPayload.upstream`	string	Upstream request URI (optional)
`severity`	string (`LogSeverity`)	Log entry level (translated).

Configure metrics collection

To ingest metrics from nginx, you must create receivers for the metrics that nginx produces and then create a pipeline for the new receivers.

To configure a receiver for your nginx metrics, specify the following fields:

Field	Default	Description
`collection_interval`	`60s`	A time duration, such as `30s` or `5m`.
`server_status_url`	`http://localhost/status`	The URL exposed by the nginx stub status module.
`type`		This value must be `nginx`.

What is monitored

The following table provides the list of metrics that the Ops Agent collects from the nginx instance.

Metric type
Kind, Type Monitored resources	Labels
`workload.googleapis.com/nginx.connections_accepted`
`CUMULATIVE`, `INT64` gce_instance
`workload.googleapis.com/nginx.connections_current`
`GAUGE`, `INT64` gce_instance	`state`
`workload.googleapis.com/nginx.connections_handled`
`CUMULATIVE`, `INT64` gce_instance
`workload.googleapis.com/nginx.requests`
`CUMULATIVE`, `INT64` gce_instance

Sample dashboard

To view your nginx metrics, you must have a chart or dashboard configured. Cloud Monitoring provides a library of sample dashboards for integrations, which contain preconfigured charts. For information about installing these dashboards, see Installing sample dashboards.

Verify the configuration

This section describes how to verify that you correctly configured the nginx receiver. It might take one or two minutes for the Ops Agent to begin collecting telemetry.

To verify that the logs are ingested, go to the Logs Explorer and run the following query to view the nginx logs:

resource.type="gce_instance"
(log_id("nginx_access") OR log_id("nginx_error"))

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

fetch gce_instance
| metric 'workload.googleapis.com/nginx.requests'
| every 1m

Troubleshooting

On most distributions, nginx comes with ngx_http_stub_status_module enabled. You can check if the module is enabled by running the following command:

sudo nginx -V 2>&1 | grep -o with-http_stub_status_module

The expected output is with-http_stub_status_module, which means the module is enabled. In rare cases, if the command returns no output, you must compile nginx from source with the -with-http_stub_status_module following the nginx public documentation.

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.