As is no surprise, the world’s media businesses are delivering more digital content, in more unique ways than ever before. And now more than ever, businesses are looking for ways to deliver that content quickly, reliably and at scale; but crucially at a cost that is manageable.

Not long ago,The Register offered this tongue-in-cheek prediction: “What sector of tech is forecast to grow fatter than the Slovakian economy or Elon Musk’s ego in 2018? The cloud. Global spending on the fluffy white stuff is predicted by mystics at Gartner to reach $175.8bn this year.” This doesn’t appear to have been an exaggeration. Acloud industry insights report from Right Scale indicated that 96% of companies across industries have embraced cloud services, for any number of reasons, including faster, more innovative delivery and cost reductions, among others. And more than half of the companies surveyed were deploying multiple clouds for different reasons as well as any number of hybrid on-premise and cloud mashups that together make up a custom solution to suit each individual company.

The countdown is on - we’re just a week away from Black Friday, meaning that you have already prepared your website to face the traffic demands it will - hopefully - face and surmount. In previous years, we’ve written about getting ready for Black Friday because it has traditionally been a peak-traffic occasion, but it has become common for outages to occur at other random peak-traffic times because there are actually other major, but sometimes predictable, traffic jams. As it happens, major shopping days are no longer limited to the Black Friday/Cyber Monday weekend each year - with the end-of-year shopping season beginning online earlier and earlier, and the biggest stumbling blocks lately happening in the US on Thanksgiving Day itself. 

Two years ago, I wrote an article about how probes work in Varnish (it's a great article - fun, informative... go read it), it covers a lot of ground, but still, it misses one important spot. More precisely, it only focused on how Varnish uses probes to know whether a backend is worth contacting, so today, we are going to look at the other side of the story: how do we tell the rest of the system that Varnish is up and ready to work?

Also, we'll see how to handle maintenance: if you need to get your Varnish node offline, it's annoying to log into all the load balancers to re-configure them; it's easier to just tell Varnish to fail incoming probes until said load balancers take the node out of their pool, and then you can wait for the active connections to end (does it ring a bell?) and then stop Varnish.

Hop on! We'll have a look at different ways of doing it - good and (mostly) bad, to try and understand how to do it and be warned of the various pitfalls to avoid.