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Varnish Cache Monitoring
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 application monitoring 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
