Cloud Computing - The Devil is in the details

Posted November 20, 2009, 5:23 pm by Yaron Levi

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Yaron Levi

Unless you were living in a cave, far from any civilization, chances are you heard about The Cloud. The next big thing! The ultimate solution for all IT business illnesses. Of course, I am exaggerating but cloud initiatives are backed by major players like Amazon, Google, Microsoft, EMC and others.


Cloud means many things to many people: if you take the infrastructure as a service (IaaS) approach the cloud is a hosting solution that will eliminate the need for companies to maintain their own hardware, for others it is a utility service that will allow businesses to consume unlimited computing resources right when they need them and release them back to the cloud when they are done. If you take the Software as a Service (SaaS) approach the cloud provides applications that are available on demand and are accessible anytime from anywhere, again without the need to maintain them internally in the organization.


If you are Larry Allison, then for you the cloud is nothing more than a vapor of water :-)


The Cloud appeals to many executives because it allows them to:

  • Turn fixed costs into variable costs.
  • Reduce software capitalization cost on new projects and installations.
  • Reduce the time to get new infrastructure resources for applications from weeks to hours.
  • Eliminate big chunk of in house staff (application developers, support staff, sys admins, network engineers etc.)
  • Eliminate the time spent on capital investment budgeting and planning.
  • Stop wasting real estate on data centers.
  • Require the cloud to maintain the operating system levels and patches under SLA.


The next step will normally be to go to the IT guys and ask them to make it happen and this is where it gets ugly. Many IT people see the cloud as a threat to their job but even with that aside there are many technical issues that make cloud adoption difficult, and as one of my friends said the devil is in the details.


Cloud ComputingPlease forgive me but I’ll get little technical here:


Cloud computing requires a lot of bandwidth, however if you ask the IT guys how much bandwidth they need you will find that most of them don’t know. Moreover, with cloud federations over the internet QoS is nonexistent. Of course all the cloud providers will tell you that they have unlimited bandwidth and they are directly connected to the internet backbone but given that you don’t know how the packets route between your network and the cloud, and you don’t know on which boxes on the cloud they will eventually land the statement about unlimited bandwidth is becoming not relevant.


It is possible to have QoS if you use a dedicated point to point connection or MPLS infrastructure (although some will argue this doesn’t qualify as cloud service) and you have to agree on QoS policy with your cloud provider. Does that policy aligns with the MPLS carriers? How many MPLS providers do you have or want to have? Can you manage QoS across providers? Even if you can do you really want to do that (believe me it is not much fun).


If you are using the internet to connect to the cloud you’ll need some public IPv4 addresses and those are running out. According to recent study 90% of the IPv4 space was already allocated and the remaining space will run out by 2011. Many cloud providers will not communicate natively with RFC1918 addresses, only public IPs. NAT is an option, but it has its own limitations and requires complex provisioning (think about sending millions of connections through a NAT to a cloud data center – doesn’t sound like too much fun).


Getting traffic to the cloud over the internet through VPN tunnel with NAT’ing will require a very good routing design. Do you know how to do it? Do you know how to configure your firewalls to support that? Do you have a completely dynamic routing design now or did you static route the internet connections because routing protocols through the firewall were too tough to design? Although all of this sounds quite technical, I can’t tell you how many politically charged meetings I have participated in when different groups in the organization fought tooth and nail over the internet connections.


The cloud providers commit to unlimited capacity and scalability and I am sure someone at the organization will love to try it out. Can your routing design scale to handle many more routes? What if you’ll need to connect to more than one cloud provider?


How is your routing protocol security? Is your core routing protocol Is BGP? How would you deal with AS-path length paths to the cloud provider over diverse ISPs? Routing technology is tough to do right and it is only understood by some very good networking people, no offense to anyone but many IT people have no concept of how hard it is to efficiently move packets from point A to point B, let alone their business executives.


When things go wrong who are you going to hold accountable? Last time I checked 1-800-INTERNET was no longer in service and most cloud providers will commit to the uptime of their service but beyond that you are on your own.


The bad news is: with clouds it is going to get harder!!!!


Don’t get me wrong, I strongly believe that cloud is an amazing technology that is here to stay. The idea of having computing power as another utility, exactly like electricity or water, makes a lot of sense and I have no doubt  we'll eventually get there but the road is not as easy as many would like to believe.


Cloud usage is growing exponentially in the last couple of years trend will continue, for now it is mainly used for Web based applications, SaaS and projects by technical savvy organizations. For many other companies, especially at the SMB space, the barrier for entry is still too high.


My advice to my fellow IT guys: there is no point resisting the change, the cloud will not eliminate IT jobs but rather shift the focus from maintaining hardware to managing connectivity, routing and security. If anything you will need to learn more and for many of us this is why we are in the IT business.


On my next post I’ll discuss some of the options to deal with several of the challenges mentioned here.

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