Overview

This check collects Varnish metrics regarding:

• Clients: connections and requests
• Cache performance: hits, evictions, etc.
• Threads: creations, failures, and threads queued
• Backends: successful, failed, and retried connections

It also submits service checks for the health of each backend.

Setup

Installation

The Varnish check is included in the Datadog Agent package. No additional installation is needed on your server.

Configuration

Prepare Varnish

If you’re running Varnish 4.1+, add the dd-agent system user to the Varnish group using:

sudo usermod -G varnish -a dd-agent

If you use a secretfile, you must ensure it is readable by the dd-agent user.

Metric collection

1. Edit the varnish.d/conf.yaml file, in the conf.d/ folder at the root of your Agent’s configuration directory. See the sample varnish.d/conf.yaml for all available configuration options.

   init_config:
   
   instances:
     - varnishstat: /usr/bin/varnishstat
       varnishadm: <PATH_TO_VARNISHADM_BIN>
   

   Note: If you don’t set varnishadm, the Agent doesn’t check backend health. If you do set it, the Agent needs privileges to execute the binary with root privileges. Add the following to your /etc/sudoers file:

     dd-agent ALL=(ALL) NOPASSWD:/usr/bin/varnishadm
   

2. Restart the Agent.

Log collection

Available for Agent versions >6.0

1. To enable Varnish logging uncomment the following in /etc/default/varnishncsa:

     VARNISHNCSA_ENABLED=1
   

2. Add the following at the end of the same file:

     LOG_FORMAT="{\"date_access\": \"%{%Y-%m-%dT%H:%M:%S%z}t\", \"network.client.ip\":\"%h\", \"http.auth\" : \"%u\", \"varnish.x_forwarded_for\" : \"%{X-Forwarded-For}i\", \"varnish.hit_miss\":  \"%{Varnish:hitmiss}x\", \"network.bytes_written\": %b, \"http.response_time\": %D, \"http.status_code\": \"%s\", \"http.url\": \"%r\", \"http.ident\": \"%{host}i\", \"http.method\": \"%m\", \"varnish.time_first_byte\" : %{Varnish:time_firstbyte}x, \"varnish.handling\" : \"%{Varnish:handling}x\", \"http.referer\": \"%{Referer}i\", \"http.useragent\": \"%{User-agent}i\" }"
   
     DAEMON_OPTS="$DAEMON_OPTS -c -a -F '${LOG_FORMAT}'"
   

3. Restart the varnishncsa utility to apply the changes.

4. Collecting logs is disabled by default in the Datadog Agent, enable it in your datadog.yaml file:

   logs_enabled: true
   

5. Add this configuration block to your varnish.d/conf.yaml file to start collecting your Varnish logs:

   logs:
     - type: file
       path: /var/log/varnish/varnishncsa.log
       source: varnish
       service: varnish
   

   Change the path and service parameter value and configure them for your environment. See the sample varnish.yaml for all available configuration options.

6. Restart the Agent.

Validation

Run the Agent’s status subcommand and look for varnish under the Checks section.

Data Collected

Metrics

Events

The Varnish check does not include any events.

Service Checks

varnish.backend_healthy
Checks the status of your different backends parsed from varnishadm. Additional information about backend status at the time of collection is included in the check message.
Statuses: ok, critical

Troubleshooting

Need help? Contact Datadog support.

Further Reading

Additional helpful documentation, links, and articles:

• Top Varnish performance metrics
• How to collect Varnish metrics
• Monitor Varnish using Datadog