At Lustratus we have been doing a lot of research into Cloud Computing, as have many firms.
I must confess the more I have dug into it, the more horrified I have become at the hype, confusion, miscommunication and manipulation of the whole Cloud Computing concept.
In the end, I decided the time was right for an Executive Guide to Cloud – defining it in as simple terms as possible and laying out the Cloud market landscape. Lustratus has just published the report, entitled “Cloud Computing without the hype; an executive guide” and available at no charge from the Lustratus store. Not only does the paper try to lock down the cloud definitions, but it also includes a summary of some 150 or so suppliers operating in the Cloud Computing space.
The paper deals with a number of the most common misunderstandings and confusions over Cloud. I plan to do a series of posts looking at some of these, of which this post is the first. I thought I would start with the Private Cloud vs Internal Cloud discussion.
When the Cloud Computing model first emerged, some were quick to try to define Cloud as a public, off-premise service (eg Amazon EC2), but this position was quickly destroyed as companies worldwide realized that Cloud Computing techniques were applicable in many different on and off premise scenarios. However, there has been a lot of confusion over the terms Private Cloud and Internal Cloud. The problem here is that analysts, media and vendors have mixed up discussions about who has access to the Cloud resources, and where the resources are located. So, when discussing the idea of running a Cloud onsite as opposed to using an external provider such as Amazon, people call one a Public Cloud and the other an Internal Cloud or Private Cloud.
This is the root of the problem. This makes people think that a Private Cloud is the same as an Internal Cloud – the two terms are often used interchangeably. However, these two terms cover to different Cloud characteristics, and it is time the language was tightened up. Clouds may be on-premise or off-premise (Internal or External), which refers to where the resources are. (Actually, this excludes the case where companies are running a mix of clouds, but let’s keep things simple). The other aspect of Cloud usage is who is allowed to use the Cloud resources. This is a Very Important Question for many companies, because if they want to use Cloud for sensitive applications then they will be very worried who else might be running alongside in the same cloud, or who might get to use the resources (eg disk space, memory, etc) after they have been returned to the cloud.
A Public Cloud is one where access is open to all, and therefore the user has to rely on the security procedures adopted by the cloud provider. A Private Cloud is one that is either owned or leased by a single enterprise, therefore giving the user the confidence that information and applications are locked away from others. Of course, Public Cloud providers will point to sophisticated security measures to mitigate any risk, but this can never feel as safe to a worried executive than ‘owning’ the resources.
Now, it is true that a Public Cloud will always be off-premise, by definition, and this may be why these two Cloud characteristics have become intertwined. However, a Private Cloud does not have to be on-premise – for example, if a client contracts with a third party to provide and run an exclusive cloud which can only be used by the client, then this is a Private Cloud but it is off-premise. It is true that USUALLY a Private Cloud will be on-premise, and hence equate to an Internal Cloud, but the two terms are not equal.
The best thing for any manager or exec trying to understand the company approach to cloud can do is to look at these two decisions separately – do I want the resources on or off premise, and do I want to ensure that the resources are exclusively for my use or am I prepared to share. It is a question of balancing risk against the greater potential for cost savings.