Contrary to mainstream reports, Cloud computing is not synonymous with virtualization. While Cloud computing and its derivatives are in their infancy, virtualization has been around since the 1960s and was first implemented by IBM 30 years ago to logically partition mainframe computers into virtual machines. With the standardization on x86 architecture in the 1990s, virtualization moved from the proprietary mainframe to commodity X86 hardware. Unlike the mainframe, X86 hardware was not designed to handle the challenges of virtualization. To overcome these challenges companies, both commercial and OSS, emerged with VMware and XenSource (Citrix) being the most widely known.
As a quick aside, once again the pundants have called for the death of the mainframe. However, IBM responded to the challenge by releasing the z/OS and specifically the z/VM hypervisor for their mainframes. For the first time, enterprises could run z/Linux on mainframes and virtualize thousands of Linux servers on a single mainframe.
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While utility, grid, and now cloud computing vendors struggled for widespread acceptance, virtualization found a niche within development and test environments. The ability to rapidly deploy and tear down virtual servers followed by the promise of server consolidation caught the eye of both enterprises and cloud vendors. The idea was brilliant, separate the operating system from the application thereby “cloud enabling” applications without waiting for the application vendors themselves. However, the reality has been quite different.
In August of 2006, Amazon released EC2 (Elastic Compute Cloud) based on the Xen hypervisor. Hailed as a “science project”, EC2 allowed users (individual, SMB, Large Enterprise, and Software Companies) to host their applications on a virtual infrastructure. While EC2 has experienced its growing pains, it has become a thought and revenue leader in cloud computing infrastructure. However, Amazon’s cloud is much more than simply the Xen hypervisor running on a server farm.
In the end, virtualization has some of the same challenges as cloud computing; manageability, security, networking, storage, etc. For the virtualization vendors, there is much revenue and market share to be gained by tying these technologies and concepts together. In fact, VMware has boldly released the Virtual Datacenter OS that proclaims to transform your datacenter into an “internal cloud.” If only it was that easy.
Repeat after me, Cloud Computing is NOT Virtualization.