nginx-exporter

A meta nginx exporter that combines two different exporters

Development Status nginx-exporter is in an early development phase.
Expect breaking changes any time.

References

• The mtail programm is based on
  google/mtail.
• The status page exporter is from
  discordianfish/nginx_exporter.
• The exporter merger is from
  rebuy-de/exporter-merger.

Available Metrics

From mtail

All metrics provide these labels: vhost, method, code, content_type.

• nginx_requests_total – Counter of processed requests.
• nginx_request_duration_milliseconds – Histogram of all response times.
• nginx_response_size_bytes_sum – Sum of all response body sizes.

The nginx_request_duration_milliseconds histogram currently defines these buckets:
100ms, 200ms, 300ms, 500ms, 800ms, 1300ms, 2100ms, 3400ms, 5500ms, +Inf

From status page

• nginx_connections_current – Number of connections currently processed by nginx (labels: state)
• nginx_connections_processed_total – Number of connections processed by nginx (labels: stage)

Also there is up and nginx_exporter_scrape_failures_total.

Configuration

Nginx

Access Logs

The exporter needs a particular access logs format, since the default format
doesn't include response times. This needs to be specified in the http
section:

log_format mtail '$host $remote_addr - $remote_user [$time_local] '
                 '"$request" $status $body_bytes_sent $request_time '
                 '"$http_referer" "$http_user_agent" "$content_type" "$upstream_cache_status"';

The access logs needs to be enabled in each server section:

access_log /var/log/nginx/mtail/access.log mtail;

Status Page

The status page is disabled by default. We suggest to listen on a separate port, so the path does not clash with any existing resource:

server {
    listen 8888;
    location /nginx_status {
      stub_status on;
      access_log  off;
      allow       127.0.0.1;
      deny        all;
    }
}

You can also keep the port private and do deny external traffic to the port.

Exporter

This exporter is configured via environment variables:

• NGINX_ACCESS_LOGS -- Path to the nginx access logs (eg
  /var/log/nginx/mtail/access.log in the example above).
• NGINX_STATUS_URI -- URI to the nginx status page (eg
  http://localhost:8888/nginx_status in the example above).

Prometheus

The exporter provides three metric endpoints:

• 3093 -- mtail exporter
• 9113 -- status page exporter
• 9397 -- merged metrics from mtail and status page exporter

Kubernetes

The exporter is supposed to run as a sidecar. Here is an example config:

apiVersion: extensions/v1beta1
kind: Deployment

metadata:
  name: my-nginx
  labels:
    app: my-nginx

spec:
  selector:
    matchLabels:
      app: my-nginx

  template:
    metadata:
      name: my-nginx
      labels:
        app: my-nginx
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "9397"

    spec:
      containers:
      - name: "nginx"
        image: "my-nginx" # nginx image with modified config file

        volumeMounts:
        - name: mtail
          mountPath: /var/log/nginx/mtail

      - name: exporter
        image: quay.io/rebuy/nginx-exporter:v1.1.0

        ports:
        - containerPort: 9397

        env:
        - name: NGINX_ACCESS_LOGS
          value: /var/log/nginx/mtail/access.log
        - name: NGINX_STATUS_URI
          value: http://localhost:8888/nginx_status

        volumeMounts:
        - name: mtail
          mountPath: /var/log/nginx/mtail

      volumes:
      - name: mtail
        emptyDir: {}