Varnish

Auto-Detection

Exporter Metrics

Auto-Detection

Glouton automatically detects Varnish when it is running on the monitored host.

Exporter Metrics

Detailed Varnish metrics are available through the third-party jonnenauha/prometheus_varnish_exporter.

Prerequisites

• Varnish Cache installed and running
• Glouton agent installed on the same host
• The varnishstat command available on the system (included with Varnish)
• Go toolchain (if building from source) or access to GitHub releases

Installing the Exporter

No special configuration is required on the Varnish side. The exporter reads metrics directly from varnishstat, which accesses Varnish’s shared memory log.

Verify that varnishstat is working:

varnishstat -1

Download the latest release from the prometheus_varnish_exporter releases page, or install with Go:

go install github.com/jonnenauha/prometheus_varnish_exporter@latest

Start the exporter:

prometheus_varnish_exporter

The exporter listens on port 9131 by default. Verify it is working:

curl http://localhost:9131/metrics

For production use, create a systemd service unit to manage the exporter process.

Glouton Configuration

Linux

sudo tee /etc/glouton/conf.d/99-varnish.conf > /dev/null << 'EOF'
metric:
  prometheus:
    targets:
      - url: "http://localhost:9131/metrics"
        name: "varnish"
        allow_metrics:
          - "varnish_main_client_req"
          - "varnish_main_cache_hit"
          - "varnish_main_cache_miss"
          - "varnish_main_backend_conn"
          - "varnish_main_threads"
          - "varnish_main_sess_conn"
EOF

Windows

Create or edit C:\ProgramData\glouton\conf.d\99-varnish.conf:

metric:
  prometheus:
    targets:
      - url: "http://localhost:9131/metrics"
        name: "varnish"
        allow_metrics:
          - "varnish_main_client_req"
          - "varnish_main_cache_hit"
          - "varnish_main_cache_miss"
          - "varnish_main_backend_conn"
          - "varnish_main_threads"
          - "varnish_main_sess_conn"

Customize collected metrics

The metrics below are our recommended defaults. You can adjust the allow_metrics list to include any metric from the prometheus_varnish_exporter GitHub repository, or use deny_metrics to exclude specific ones. See Metrics Filtering for details.

Metric	Description
varnish_main_client_req	Total number of client requests received
varnish_main_cache_hit	Total number of cache hits
varnish_main_cache_miss	Total number of cache misses
varnish_main_backend_conn	Total number of backend connections made
varnish_main_threads	Number of threads in all pools
varnish_main_sess_conn	Total number of sessions accepted