Blockchain fever has finally reached mainstream status with more than a thousand listed cryptocurrencies, and we feel that the world needs our contribution in this domain. This is why we are announcing the Varnish Cash solution.
As you may know, part of my job consists of helping Varnish users, both customers and community users (join us on IRC!), often looking at their VCL and see if there's anything wrong. And sometimes, there is. After all, VCL is a programming language and mistakes happen. However, one point stands out as being badly understood, and I feel it deserves a short blog post to set the record straight.
Varnish is a powerhouse, and a lot of the use cases you'll see about it are about delivering stellar performance, specially in CDN contexts. But today I'd like to share a more intimate setup that I came across recently, where Varnish shone not because of its perfomance but rather thanks to its flexibility. This should give you some ideas on how to use it more, notably back within the confines of your infrastructure.
Some time ago, we discussed backend pools and how to load-balance inside them using directors, remember? During the first post I hinted at forcing backends to "sick" before maintenance of a backend but didn't go into more detail. Today it's time to have a short yet closer look at how you can cleanly take a backend out and insert it again.