Category Archives for Varnish

How to Confirm SNS Subscription and Fix PendingConfirmation Subscription

I have been trying to confirm SNS Subscription. But It just keep showing “PendingConfirmation”. After searching in aws forum, I found that they send a POST request instantly. So I began searching for “Amazon Simple Notification Service Agent” in access … Continue reading

18. December 2014 by Zakir Hyder
Categories: Server Management, Varnish, Web Development | Tags: , , , , , | Comments

Beware of Varnish hit_for_pass

Little back story: I am very much fond of Move Fast and Break Things. I am playing with varnish last 3 months. We let go 2 programmers this month and the work load increase 2x. This should not be an … Continue reading

24. November 2014 by Zakir Hyder
Categories: Linux, Varnish | Comments

Setting Up Varnish Security Firewall

Varnish can add a extra layer of security as well as HTTP accelerator. https://github.com/comotion/VSF is a Web Application Firewall (WAF) written using the Varnish Control Language (VCL) and a sprinkling of Varnish Modules (vmods). If you want to know how … Continue reading

01. October 2014 by Zakir Hyder
Categories: Ubuntu, Varnish | Tags: , , , , , , | Comments

Building a Varnish VMOD

Building a Varnish VMOD in ubuntu is bit complicated process. we are going to use varnish-3.0.5. For VMOD we are going to use https://github.com/varnish/libvmod-shield. Lets create a folder and get the varnish’s source code. Then we will create a make … Continue reading

28. September 2014 by Zakir Hyder
Categories: Linux, Ubuntu, Varnish | Tags: , , , , , , | Comments

Varnish BackendPolling

BackendPolling can reduce Varnish 503 errors. Varnish poll by opening a new TCP connection to the backend on which we send a preconfigured request, wait for the answer and the connection to be closed by the backend. Only if Varnish … Continue reading

16. September 2014 by Zakir Hyder
Categories: Linux, Varnish | Tags: , , , , | Comments

Fixing Varnish’s 503 Error

I have been trying to speed up somewhereinblog.com. Among many other things, I am trying to add Varnish cache. While setting Varnish on our test server, I have been facing 503 error. Basically this means that backend not responding correctly … Continue reading

12. May 2014 by Zakir Hyder
Categories: Caching, Varnish | Tags: , , , , , , | Comments