Businesses have many options for virtualization, and each choice comes with its own disk formats, management models, and interfaces. For organizations with mixed environments, as well as software and hardware vendors who want to offer heterogeneous solutions, the resulting complexity creates significant challenges.
Fortunately, efforts in the industry are beginning to yield standardization - reducing the complexity associated with choice.
The Xen hypervisor itself has emerged as an open standard for virtualization on x86 systems (and, increasingly, on other architectures as well). The presence of Xen in Linux distributions as well as in the Citrix XenServer platform virtualization solution provides interoperability between OS-centric and platform virtualization deployments. Xen is also seen now in other x86-based operating system environments, including Solaris and BSD distributions - making it possible to deploy a diverse Xen-virtualized environment.
The latest versions of the standard Linux kernel from kernel.org introduces a new standard interface called paravirt_ops. This interface makes it possible for off-the-shelf Linux kernels to run with a variety of virtualization choices, as well as on bare metal, without modification. Xen users can count on their distributions incorporating high-performance Xen-ready kernels.
The Common Information Model (CIM) provides a common definition of management information for systems, networks, applications and services, and allows for vendor extensions. CIM’s common definitions enable vendors to exchange semantically rich management information between systems throughout the network. The Distributed Management Task Force (DMTF) System Virtualization, Partitioning, and Clustering Working Group is developing a model schema and management methods for virtualization. A Xen community working group is developing a in implementation for Xen, which will simplify management integration.
The virtual disk formats implemented in some virtualization products have been documented and licensed for the development of virtual machine portability. Citrix XenServer products support the import of VMware VMDK and Microsoft VHD formats, making it possible to bring virtual machines to the platform easily. This documentation is a first step toward more portable formats that can be used across multiple platforms.