Crossroads - Spring 2010

Figure 2: The top 500,000 sites by cloud provider are shown.

Figure 3: The chart shows resource usage of Amazon EC2 in the eastern United States in September 2009 over a 24-hour period.

Second, Amazon EC2 leads the cloud infrastructure industry by a wide margin. Amazon is reaping the rewards of being the innovating pioneer. Its first cloud service was launched as early as 2005 and the richness of its offering is at present unmatched.

The second study we’ll discuss examined the overall usage of Amazon EC2, based on publicly-available data that had been overlooked. Every time you provision a resource from Amazon EC2 (for example, request to start a new server instance) that resource is assigned an ID, such as i-31a74258. The ID is an opaque number that is used to refer to the resource in subsequent commands.

In a simplistic scenario, that ID would be a serial number that increments each time a resource is provisioned. If that were the case, we could perform a very simple yet powerful measurement: we could provision a resource and record its ID at a certain point in time. Twenty-four hours later, we could perform the same action, again recording the ID. The difference between the two IDs would represent the number of resources provisioned within the 24-hour period.

Unfortunately, at first glance Amazon EC2’s IDs appear to have no meaning at all and are certainly not trivial serial numbers. A mixture of luck and investigations began to reveal patterns in the IDs. One by one, these patterns were isolated and dissected until it was discovered that underlying the seemingly opaque ID there is, after all, an incrementing serial number.

For example, the resource ID 31a74258 can be translated to reveal the serial number 00000258. (This process was published in detail and can be found in the blog post Anatomy of an Amazon EC2 Resource ID: www.jackofallclouds.com/2009/09/anatomy-of-an-amazon-ec2- resource-id.) With these serial numbers now visible, we can perform our measurement as described above. Indeed, during a 24-hour period in September 2009 the IDs for several types of resources were recorded, translated and the resource usage calculated from the differences. See Figure 3.

Over the 24-hour period observed, the quantities of resources provisioned were:

• Instances (servers): 50,242

• Reservations (atomic commands to launch instances): 41,121

• EBS volumes (network storage drives): 12,840

• EBS snapshots (snapshots of EBS volumes): 30,925.

These numbers are incredible to say the least. They show the use of
Amazon EC2 to be extensive as well as dynamic. We should recall that
these numbers represent the number of resources created and do not
provide clues to how many of them exist at any given point in time, be-
cause we do not know which resources were later destroyed and when.

Is the Cloud Good for Business?

What’s driving adoption is the business side of the equation. We can fold the benefits of the cloud into two primary categories: economics and focus.

The first and foremost of the cloud’s benefits is cost. Informal polls among customers of IaaS suggest that economics trumps all other factors. Instead of large up-front payments, you pay as you go for what you really use. From an accounting point of view, there are no assets on the company’s balance sheet: CAPEX (capital expenditure) becomes OPEX (operating expenditure), an accountant’s dream!

When it comes to IT, economies of scale matter. Maintaining 10,000 servers is cheaper per server than maintaining one server alone. Simple geographic factors also come into play: whereas an on-premise server must be powered by the electricity from your local grid, cloud datacenters are often constructed near sources of low-cost electricity such as hydroelectric facilities (so the cloud is good for the environment as well). These cost savings can then be passed on to customers.

The second reason you might use the cloud is in order to focus on your core competencies and outsource everything else. What is the benefit of holding on to on-premise servers, air conditioned server rooms and enterprise software—not to mention the IT staff necessary to maintain them—when you can outsource the lot? In the new model, your company, be it a legal firm, a motor company, or a multinational bank, focuses on its core business goals. The cloud companies, in turn, focus on their core competency, providing better, more reliable and cheaper IT. Everyone wins.