Don't Use Cloud Middleware
I’ve been working on various “cloudification” projects lately and something that has come up multiple times is that we should not write any sort of automation or scripting against the “native” APIs provided by the cloud providers themselves. Even if - for now - the project will run solely on vMware or Amazon AWS, we should look to the future and assume that we will either be using multiple cloud providers or at the very least make it non-painful to switch from one to the other.
And this is laudable! I either agreed wholeheartedly or even said that myself. The impulse is sound and might be likened to the bad old days of writing non-portable code in C, so that switching from big to little-endian CPUs (or vice versa) could result in a large, nasty porting effort. But I think the trade-off in this case is a mirage, or at least not worth the effort.
Let’s examine the reasons to use a middle-ware layer vs. hitting the native APIs and see if any of the hold up under scrutiny.
- You don’t want to be locked into a single vendor
- You don’t want to have to learn multiple APIs / how things work behind the scenes.
- You happen to use the same language in the rest of your project that the middle-ware layer does (ruby/fog, java/jclouds, python/libcloud, etc.)
- You want to be able to support “all” of the cloud providers out there. Each library claims to support over 30!
Starting with the first and most easily dismissed concern - vendor lock-in. So you don’t want to be tied to a single vendor. That’s nice! What - exactly - do you think is happening when you write all of your code against a single API, whether that API is provided “for free” by the folks writing fog, or by the people at Amazon? You’re still locked in. If fog is abandoned or no longer fits your needs, you’d still have to port all of your code to something else, and if you go to another middle-ware library, there is a really good chance you’d have to throw out all of your code and start from scratch in another language. Or - in your copious amounts of free time - you can also start supporting an opensource project (that was apparently unsuccessful enough that it was abandoned in the first place). Oh and by the way: the internet is littered with the bones of projects that thought this was going to be a super-neat thing to do and then died as people lost interest.
The second reason - you don’t want to have to learn multiple APIs and how things really work - is equally laughable. Every platform has its quirks, and no library can make those magically go away. Do you want to be able to move virtual machines from one hypervisor to another? Completely ordinary using VMware’s ESXi, completely impossible with Amazon’s AWS. In ESX you don’t even have to shut the VM down, assuming you have shared storage and matching hardware1. In AWS you have to shut down the machine and start it back up (a reboot is insufficient), and even then you’re just hoping you don’t get the same hypervisor - you have no direct control. If you are building a dashboard to manage machines, you still have to code logic for handling this. So what are you saving again?
Reason #3, the language of your project matches that of the middle-ware layer. That’s short-sighted in two respects. First of all, at least in my experience, there is no such thing as a shop that writes everything exclusively in one language. Sure, their “main” product might be in php, but what about all of the tooling that springs up where ever developers and sysadmins tread? Java for the atlassian tools forced on them by management, ruby for chef or puppet, perl for the web service written by someone that hasn’t worked there for five years but it still serves its purpose, we all end up polyglots, in any shop larger than two people. Are you going to force all tooling for everything interacting with servers to be written in one language?
And fourth, while having the “flexibility” to use ALL THE CLOUD PROVIDERS at will, again I don’t buy it. Most places end up with one, maybe two providers, because the downsides (only being able to use the least-common denominator of the features that they have, increased complexity in, well, everything, etc.) outweigh the advantanges of /not/ doing that. If you’re worried about uptime, then use the existing facilities to ensure that your site is spread across multiple DCs. Worried about someone increasing their prices? I think you’ll find the cost of “porting” your infrastructure somewhere else far outweighs almost all cost bumps, for sites of any reasonable size.
Finally, instead of being tied to the vendor that’s providing you the actual service (and can presumably help you if you have problems), you’re tying yourself to a project with whom you have no relationship and no support contract. A 3rd party that doesn’t know the roadmap of the vendors, so they can’t build-out new APIs before features are released, but have to “catch up” afterwards. Went to AWS Conf and saw them release something neat? Cool, now go back home and wait for a couple of months for your 3rd party to add support for it. Or, you go “around” the middle-ware and hit the vendor’s APIs directly. Remind me what you’re saving again?
- See? more quirks that you know, that a 3rd party vendor wouldn’t. [return]