The Varnish integration collects cache and session metrics. It monitors the number of objects entering and exiting the cache, as well as the number of sessions and backend connections. The integration also collects Varnish logs and parses them into a standardized JSON payload.
For more information about Varnish, see the Varnish HTTP Cache documentation.
Prerequisites
To collect Varnish telemetry, you must install the Ops Agent:
- For metrics, install version 2.15.0 or higher.
- For logs, install version 2.16.0 or higher.
This integration supports Varnish versions 6.x and 7.0.x.
Configure your Varnish instance
The Varnish logging processor processes logs using varnishncsa. Varnish can enable varnishncsa logging by following this guide, depending on the operating system.
By default, logs are written to /var/log/varnish/varnishncsa.log
. If you
choose another destination, you must update the receiver configuration.
Logs are expected to be in the default format, and a log rotation should be
set up.
Configure the Ops Agent for Varnish
Following the guide to configure the Ops Agent, add the required elements to collect telemetry from Varnish instances, and restart the agent.
Example configuration
The following command creates the configuration to collect and ingest telemetry for Varnish and restarts the Ops Agent on Linux.
Configure logs collection
To ingest logs from Varnish, you must create receivers for the logs that Varnish produces and then create a pipeline for the new receivers.
To configure a receiver for your varnish
logs, specify the following
fields:
Field | Default | Description |
---|---|---|
exclude_paths |
A list of filesystem path patterns to exclude from the set matched by include_paths. | |
include_paths |
[/var/log/varnish/varnishncsa.log] |
A varnishncsa default log path to read by tailing each file. |
type |
This value must be varnish . |
|
record_log_file_path |
false |
If set to true , then the path to the specific file from which the log record was obtained appears in the output log entry as the value of the agent.googleapis.com/log_file_path label. When using a wildcard, only the path of the file from which the record was obtained is recorded. |
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
is derived from the receiver IDs specified in the configuration.
Detailed fields inside the
LogEntry
are as follows.
varnish
logs contain the following fields in the LogEntry
:
Field | Type | Description |
---|---|---|
httpRequest.protocol |
string | Protocol used for the request |
httpRequest.referer |
string | Contents of the Referer header |
httpRequest.remoteIp |
string | The IP address (IPv4 or IPv6) of the client that issued the HTTP request |
httpRequest.requestMethod |
string | HTTP method |
httpRequest.requestUrl |
string | Request URL (typically just the path part of the URL |
httpRequest.responseSize |
string | Response size |
httpRequest.status |
string | HTTP status code |
httpRequest.userAgent |
string | Contents of the User-Agent header |
jsonPayload.host |
string | Contents of the Host header |
jsonPayload.user |
string | Authenticated username for the request |
Configure metrics collection
To ingest metrics from Varnish, you must create receivers for the metrics that Varnish produces and then create a pipeline for the new receivers.
To configure a receiver for your varnish
metrics, specify the following
fields:
Field | Default | Description |
---|---|---|
cache_dir |
This specifies the cache dir instance name to use when collecting metrics. If not specified, defaults to the host. | |
collection_interval |
60s | A time.Duration value, such as 30s or 5m . |
exec_dir |
The directory where the varnishadm and varnishstat executables are located. If not provided, the user's PATH setting is used. |
|
type |
This value must be varnish . |
What is monitored
The following table provides the list of metrics that the Ops Agent collects from the Varnish instance.
Metric type | |
---|---|
Kind, Type Monitored resources |
Labels |
workload.googleapis.com/varnish.backend.connection.count
|
|
CUMULATIVE , INT64 gce_instance |
kind
|
workload.googleapis.com/varnish.backend.request.count
|
|
CUMULATIVE , INT64 gce_instance |
|
workload.googleapis.com/varnish.cache.operation.count
|
|
CUMULATIVE , INT64 gce_instance |
operation
|
workload.googleapis.com/varnish.client.request.count
|
|
CUMULATIVE , INT64 gce_instance |
state
|
workload.googleapis.com/varnish.client.request.error.count
|
|
CUMULATIVE , INT64 gce_instance |
status_code
|
workload.googleapis.com/varnish.object.count
|
|
GAUGE , INT64 gce_instance |
|
workload.googleapis.com/varnish.object.expired
|
|
CUMULATIVE , INT64 gce_instance |
|
workload.googleapis.com/varnish.object.moved
|
|
CUMULATIVE , INT64 gce_instance |
|
workload.googleapis.com/varnish.object.nuked
|
|
CUMULATIVE , INT64 gce_instance |
|
workload.googleapis.com/varnish.session.count
|
|
CUMULATIVE , INT64 gce_instance |
kind
|
workload.googleapis.com/varnish.thread.operation.count
|
|
CUMULATIVE , INT64 gce_instance |
operation
|
Sample dashboard
To view your Varnish metrics, you must have a chart or dashboard configured. Cloud Monitoring provides a library of sample dashboards for integrations, which contain preconfigured charts. For information about installing these dashboards, see Installing sample dashboards.
Verify the configuration
This section describes how to verify that you correctly configured the Varnish receiver. It might take one or two minutes for the Ops Agent to begin collecting telemetry.
To verify that the logs are ingested, go to the Logs Explorer and run the following query to view the Varnish logs:
resource.type="gce_instance"
logName=("projects/PROJECT_ID/logs/varnish")
To verify that the metrics are ingested, go to Metrics Explorer and run the following query in the MQL tab.
fetch gce_instance
| metric 'workload.googleapis.com/varnish.backend.connection.count'
| every 1m
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.