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Varnish Cache Monitoring

Requires Opsview 6
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Opsview Supported

Varnish Cache Opspack

Varnish Cache is a HTTP accelerator designed for dynamic, content-heavy web sites as well as heavily consumed APIs. You can install it in front of any server that speaks HTTP and configure it to cache the contents. It typically speeds up delivery with a factor of 300 - 1000x, depending on your architecture. In addition to its performance, one of the key features of Varnish Cache is the flexibility of VCL (its configuration language). VCL enables you to write policies on how incoming requests should be handled.

What You Can Monitor

Our Varnish Cache Opspack allows you to pull vital information from your environment including connection information, number of sessions/client requests, thread statistics and much more.

Note: This Opspack has been tested and configured against Varnish Cache 4.0 and 5.0. To monitor Varnish Cache 3.0, use Application - Varnish Cache 3.0 Opspack.

Service Checks

Service Check Description
backend_busy Checking varnish cache too many backend connections
backend_connections Checking varnish cache backend connections
backend_fail Checking varnish cache backend connections failed
backend_recycle Checking varnish cache backend connections recycled
backend_req Checking varnish cache backend requests
backend_retry Checking varnish cache backend connections retried
backend_reuse Checking varnish cache backend connections reused
backend_unhealthy Checking varnish cache backend connections not attempted
cache_hit Checking varnish cache hits
cache_hitpass Checking varnish cache hits for pass
cache_miss Checking varnish cache misses
client_requests Checking varnish cache client requests received
connected_sessions Checking varnish cache accepted connections
expired_objects Checking varnish cache number of expired objects
failed_threads Checking varnish cache hits total number of failed threads
hit_miss_ratio Checking varnish cache too many backend connections
nuked_objects Checking varnish cache number of nuked objects
session_queued Checking varnish cache sessions queued for thread
sessions_dropped Checking varnish cache dropped sessions
threads Checking varnish cache hits total number of threads
threads_limited Checking varnish cache times threads hit max
threads_queue Checking varnish cache length of session queue

Setup Varnish Cache for Monitoring

This Opspack uses the Opsview Linux Agent, therefore you will need the Opsview Agent installed on the same location you have Varnish Cache running.

For more information, refer to Opsview Knowledge Center - Installing Opsview Agents.

Setup and Configuration

To configure and utilize this Opspack, you need to add the 'Application - Varnish Cache' Opspack to your Opsview Monitor system.

Step 1: Add the Host Template

Add the Application - Varnish Cache Host Template to your Opsview Monitor host.

For more information, refer to Opsview Knowledge Center - Adding Host Templates to Hosts.

Step 2: Add and configure variables for this host

Variable Description
VARNISHCACHE_INSTANCE Used to give an identifier to your varnish cache instance. Use this when running multiple varnish cache instances. Each instance will need to be its own host.

For more information, refer to Opsview Knowledge Center - Adding Variables to Hosts.

Step 3: Apply changes and the system will now be monitored

Varnish Cache Service Checks