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 nginx.org.

Prerequisites

To collect and ingest nginx logs and metrics, you must install Ops Agent version 2.1.0 or higher.

This receiver 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/status for the status page. To enable the stub_status module, complete the following steps:

1. 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.

2. Add the following lines to the server section:

   location /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 /status {
          stub_status on;
          access_log off;
          allow 127.0.0.1;
          deny all;
      }
      location / {
          root /dev/null;
      }
   }
   

3. 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 /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/status

The sample output is:

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

Note: 127.0.0.1 can be replaced with the real server name, for example, server_name mynginx.domain.com. The curl command to verify would be curl http://mynginx.domain.com:80/status.

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 logs and metrics from your nginx instances, and restart the agent.

Example configuration

The following command creates the configuration file to collect and ingest logs and metrics for nginx and restarts the Ops Agent on Linux.

sudo tee /etc/google-cloud-ops-agent/config.yaml > /dev/null << EOF
logging:
  receivers:
    nginx_access:
      type: nginx_access
    nginx_error:
      type: nginx_error
  service:
    pipelines:
      nginx:
        receivers:
          - nginx_access
          - nginx_error
metrics:
  receivers:
    nginx:
      type: nginx
      stub_status_url: http://127.0.0.1:80/status
  service:
    pipelines:
      nginx:
        receivers:
          - nginx
EOF
sudo service google-cloud-ops-agent restart

Configure logs collection

To ingest logs from nginx, you must create receivers for the logs 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
type		The value must be nginx_access.
include_paths	[/var/log/nginx/access.log]	The log files to read.
exclude_paths		The log files to exclude, if include_paths contains a glob or directory.
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 nginx_error logs, specify the following fields:

Field	Default	Description
type		The value must be nginx_error.
include_paths	[/var/log/nginx/error.log]	The log files to read.
exclude_paths		The log files to exclude, if include_paths contains a glob or directory.
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.

What is logged

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

nginx_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.remoteIp	string	Client IP address
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 (usually not reported by nginx)
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.

nginx_error logs contain the following fields in the LogEntry:

Field	Type	Description
jsonPayload.level	string	Log entry level
jsonPayload.pid	number	Process ID
jsonPayload.tid	number	Thread ID
jsonPayload.connection	number	Connection ID
jsonPayload.message	string	Log message
jsonPayload.client	string	Client IP address (optional)
jsonPayload.server	string	Nginx server name (optional)
jsonPayload.request	string	Original HTTP request (optional)
jsonPayload.subrequest	string	Nginx subrequest (optional)
jsonPayload.upstream	string	Upstream request URI (optional)
jsonPayload.host	string	Host header (optional)
jsonPayload.referer	string	Referer header (optional)
severity	string (LogSeverity)	Log entry level (translated)
timestamp	string (Timestamp)	Time the entry was logged

Configure metrics collection

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

Field	Default	Description
type		The value must be nginx.
stub_status_url	http://localhost/status	The URL exposed by the nginx stub 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 nginx instance.

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

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 Nginx Overview dashboard from the Sample library and view charts that display your nginx metrics.

Verify the configuration

You can use the Logs Explorer and Metrics Explorer to verify that you correctly configured the nginx 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 nginx logs:

resource.type="gce_instance"
logName=("projects/PROJECT_ID/logs/nginx_error" OR "projects/PROJECT_ID/logs/nginx_access")

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/nginx.requests'
| align rate(1m)
| 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.