Cloud computing hard truth No. 6: Security is still a mystery
At first glance, it looks like you completely control your machine. You and you alone set the root password. If the OS is secure and the patches are installed, you should be set, right? But all of the clouds are far from clear about what is really going on underneath where the hypervisor lives.
One cloud tech told me that the versions of Linux his company sold came with bastardized monitoring utilities to block the customers from seeing some of the extra backdoors they had installed themselves. It was all for the good of the customer, he said, and he was probably right most of the time.
The cloud companies are working on securing their machines by partitioning the networks and locking down access. However, they have a long way to go before they can offer anything as secure as a locked cage in the server room of your home office.
Cloud computing hard truth No. 7: Calculating cost is no easy algorithm
It looks simple: The providers sell you something by the hour for pennies. Heck, you can afford a few pennies, right? But should you buy one faster machine for 7 cents an hour or three slower machines for 2.5 cents an hour? Each shop charges slightly differently for bandwidth, storage, and other features.
Expect to spend hours benchmarking your application on various sizes of servers. Then put all of this data into a spreadsheet to determine the cheapest configuration.
Cloud computing hard truth No. 8: Moving data is not easy
You've been smitten by the idea of buying the machines by the hour, but buying the machine is often the smallest part of the job. Getting your data into the distant racks in the cloud can be a substantial chore. If you're loaded down with log files or big, big data sets, you could be spending a long time just moving the data where you need it to be.
The best configurations are making it easier to store data locally, then buy computation time when you need it. Amazon even has its intriguing storage Glacier that's much cheaper than its regular cloud, but only promises that the data will be available in hours (hours!).
Cloud computing hard truth No. 9: Little is guaranteed
The marketing message may try to imply that the magical cloud will lift all of these responsibilities from your shoulders, but those are just the warm, fuzzy feelings from the department of warm, fuzzy feelings. The legal department buries scary things in that sea of words you clicked past when you were experimenting.
If you think that the cloud will save you from the responsibility of backing up your data, you're mistaken. Underneath it all, the machines are as fragile as the machines on your desk. They're built from many of the same components. The cloud companies don't have access to magical disk drives and chips.
The best clouds are starting to be upfront about their guarantees. Some have terms of service that explain a bit better what they do and don't cover. They are also starting to surface geographic differences, and that's making it easier to understand what you have to do when you're designing your server farm. If you want your data backed up across the country, you must design it into your system and pay for the bandwidth to carry that data.