Varnish

Plugin: python.d.plugin Module: varnish

Overview

This collector monitors Varnish metrics about HTTP accelerator global, Backends (VBE) and Storages (SMF, SMA, MSE) statistics.

Note that both, Varnish-Cache (free and open source) and Varnish-Plus (Commercial/Enterprise version), are supported.

It uses the varnishstat tool in order to collect the metrics.

This collector is supported on all platforms.

This collector only supports collecting metrics from a single instance of this integration.

netdata user must be a member of the varnish group.

Default Behavior

Auto-Detection

By default, if the permissions are satisfied, the varnishstat tool will be executed on the host.

Limits

The default configuration for this integration does not impose any limits on data collection.

Performance Impact

The default configuration for this integration is not expected to impose a significant performance impact on the system.

Metrics

Metrics grouped by scope.

The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.

Per Varnish instance

These metrics refer to the entire monitored application.

This scope has no labels.

Metrics:

Metric	Dimensions	Unit
varnish.session_connection	accepted, dropped	connections/s
varnish.client_requests	received	requests/s
varnish.all_time_hit_rate	hit, miss, hitpass	percentage
varnish.current_poll_hit_rate	hit, miss, hitpass	percentage
varnish.cached_objects_expired	objects	expired/s
varnish.cached_objects_nuked	objects	nuked/s
varnish.threads_total	None	number
varnish.threads_statistics	created, failed, limited	threads/s
varnish.threads_queue_len	in queue	requests
varnish.backend_connections	successful, unhealthy, reused, closed, recycled, failed	connections/s
varnish.backend_requests	sent	requests/s
varnish.esi_statistics	errors, warnings	problems/s
varnish.memory_usage	free, allocated	MiB
varnish.uptime	uptime	seconds

Per Backend

This scope has no labels.

Metrics:

Metric	Dimensions	Unit
varnish.backend	header, body	kilobits/s

Per Storage

This scope has no labels.

Metrics:

Metric	Dimensions	Unit
varnish.storage_usage	free, allocated	KiB
varnish.storage_alloc_objs	allocated	objects

Alerts

There are no alerts configured by default for this integration.

Setup

Prerequisites

Provide the necessary permissions

In order for the collector to work, you need to add the netdata user to the varnish user group, so that it can execute the varnishstat tool:

usermod -aG varnish netdata

Configuration

File

The configuration file name for this integration is python.d/varnish.conf.

You can edit the configuration file using the edit-config script from the Netdata config directory.

cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config python.d/varnish.conf

Options

There are 2 sections:

• Global variables
• One or more JOBS that can define multiple different instances to monitor.

The following options can be defined globally: priority, penalty, autodetection_retry, update_every, but can also be defined per JOB to override the global values.

Additionally, the following collapsed table contains all the options that can be configured inside a JOB definition.

Every configuration JOB starts with a job_name value which will appear in the dashboard, unless a name parameter is specified.

Config options

Name	Description	Default	Required
instance_name	the name of the varnishd instance to get logs from. If not specified, the local host name is used.		yes
update_every	Sets the default data collection frequency.	10	no
priority	Controls the order of charts at the netdata dashboard.	60000	no
autodetection_retry	Sets the job re-check interval in seconds.	0	no
penalty	Indicates whether to apply penalty to update_every in case of failures.	yes	no
name	Job name. This value will overwrite the job_name value. JOBS with the same name are mutually exclusive. Only one of them will be allowed running at any time. This allows autodetection to try several alternatives and pick the one that works.		no

Examples

Basic

An example configuration.

job_name:
  instance_name: '<name-of-varnishd-instance>'

Troubleshooting

Debug Mode

To troubleshoot issues with the varnish collector, run the python.d.plugin with the debug option enabled. The output should give you clues as to why the collector isn't working.

• Navigate to the plugins.d directory, usually at /usr/libexec/netdata/plugins.d/. If that's not the case on your system, open netdata.conf and look for the plugins setting under [directories].

  cd /usr/libexec/netdata/plugins.d/

• Switch to the netdata user.

  sudo -u netdata -s

• Run the python.d.plugin to debug the collector:

  ./python.d.plugin varnish debug trace