Recently, Amazon Web Services announced the availability of Amazon EC2 Dedicated Instances to meet the needs of enterprise customers they are trying to lure. After the revamp of their VPC offering, this is another surprise from Amazon aimed squarely at the enterprise customers worried about multi-tenancy. With Amazon EC2 dedicated instances, enterprise customers can get single tenant instances with no one else sharing the physical hardware running these instances. They pay a premium to cover the cost inefficiencies that are associated with such offerings.
After Amazon announced the dedicated instances, many in the Clouderati and media questioned whether it is a cloud or not. Even I debated about whether it is a public cloud or private cloud with fellow members of Clouderati community. My argument is that multi-tenancy is one of the defining characteristic of the public cloud and dedicated instances are single-tenant and hence it is #notacloud (a Twitter hashtag popularized by Sam Johnston to dismiss the idea of private cloud). To be specific, I believe Amazon Dedicated instances are, in fact, cloud but they can only be categorized as private cloud (thereby, legitimizing the very idea of private clouds).
One of the prominent public cloud advocate and founder of Cloudscaling, Randy Bias, wrote a blog post two days back trying to dispel some of the myths regarding Amazon Dedicated Instances. As it is normal in any of the Randy’s posts, this post also offered valuable insights. He dispelled some of the myths regarding Amazon dedicated instances with regards to pricing and security. In fact, I agree with most of what he has said in that post. But I have a problem with how he has implied multi-tenancy to put Amazon dedicated instances in the category of public clouds.
Taking aside the definition of ‘multi-tenancy’ and whether it’s a core property, it should be noted that clouds ‘share’ many resources, of which the CPU/server is only one. They also can share storage, networking, billing systems, etc.
Randy goes on to imply that since Amazon’s dedicated instances share network, storage, billing systems, etc. and, hence, they are still public clouds in the flavor of multi-tenant EC2 instances. If my interpretation of Randy is correct, then I think I disagree with him. I would argue that sharing of servers are equally important while considering multi-tenancy along with network, storage, billing, etc..
Let me try to put forward my, still incomplete, thoughts below and I encourage you to hound on these arguments. Please keep in mind that my arguments below are not just against Randy’s arguments but it was based on what I heard from many other public cloud advocates.
- When the idea of private clouds were introduced, it was dismissed outright because they are not multi-tenant. Public cloud purists (I was one of them at that time) argued that even if the private cloud is hosted on third party datacenters, they are not cloud because it is a single tenant environment. If we use Randy’s arguments above, these hosted private clouds should then be considered to be on par with Amazon Dedicated Instances. Well, one can bring in the scale argument but scale matters only as much as the organization using the private cloud needs it. There is no point in having the ability to scale just because they can. Plus, the third party datacenter offering hosted private clouds should be able to meet the scaling needs of most of the enterprises without adding any capital expenses to these customers. If the hosted private clouds are #notacloud, Amazon dedicated instances are not either.
- If Amazon dedicated instances, where multi-tenancy happens at network, storage, etc., can be cloud, why not managed hosting where dedicated servers share network and billing? Why not VPS where they even share servers? Why not shared hosting? I can go on and on and on. In my opinion, we can only call something as a cloud if it satisfies all of the essential characteristics of a cloud. I do believe in the NIST definition of cloud computing and hence I am ok with considering Amazon dedicated instances as a part of the cloud. Public cloud purists who have an even more puritan view of cloud cannot call a single tenant model as a cloud. Period. If they want to be flexible enough to consider Amazon dedicated instances as a cloud, they have to agree that private cloud is an acceptable use of the cloud terminology.
- From my point of view, this move by Amazon is a great pragmatic move. After their aggressive cloud push, they are finally seeing the market reality and are reacting to it. This, along with the recent VPC revamp, will go a long way in convincing most enterprises (except the ones in a highly regulated space) to use public clouds. It is a big win for cloud computing, in general.
- This move puts more and more pressure on Rackspace and GoGrid who were touting their experience in the managed hosting world as a differentiator against AWS.
- I disagree with some of the criticism on premium pricing of this offering. It is about choice. If some organizations want to pay more money and get a single tenant environment inside AWS, they should be able to do it. For me, being thrift is not a characteristic of cloud computing.
In short, if once attribute characteristics to cloud computing, we cannot change it just because Amazon wants to do differently. Then, we can as well point all the definitions of cloud computing to AWS website and STFU. It is time for us to have an independent definition of cloud computing and let the market pressure push Amazon to play around it. What is happening now is that many of the public cloud advocates are tweaking their definition of cloud computing around Amazon’s offerings. I think it has the danger of diluting cloud computing than any FUD from traditional IT vendors. Any thoughts? I strongly encourage you to poke around my arguments. It helps me because I am not really religious about the cloud definition.
- What does Multi-Tenant Mean to You? (securecloudreview.com)
- Cloud Computing & Cost Benefits (cleanclouds.wordpress.com)
- Multi-tenancy: emulation or the real thing? (zdnet.com)
- Dedicated AWS VPC Compute Instances – Strategically Defensive or Offensive? (rationalsurvivability.com)
- Amazon’s cloud new offers dedicated hardware (infoworld.com)
- Amazon offers dedicated servers on EC2 (go.theregister.com)
- Here’s Why Cloud Computing Is So Hot Right Now (businessinsider.com)
- Amazon Web Services Adds an Un-Cloudy Option to Its IaaS (readwriteweb.com)