In this article you will read about 

• why the Open Telekom Cloud will rely on KVM instead of Xen in the future,
• the benefits of the KVM hypervisor, and
• why companies should now switch from Xen-based flavors to KVM flavors.

The Open Telekom Cloud will in future rely exclusively on the Kernel-based Virtual Machine (KVM) hypervisor. Previously, a number of flavors and services based on the previous virtualization technology, Xen, were still available. Now all flavors of the Elastic Cloud Server offering and dedicated hosts based on Xen will be switched off by August 31, 2020 and replaced by KVM-based alternatives. Companies currently using flavors such as Disk Intensive I or High Performance I based on the previous Xen hypervisor should therefore migrate to an equivalent KVM flavor now. SAP Netweaver flavors are an exception to this rule.  

The following table shows the affected Xen flavors together with their KVM equivalent:

Other Open Telekom Cloud services also affected by the changeover are the Elastic Load Balancer, Relational Database Service and Cloud Container Engine. Users of these services will be contacted separately by Telekom.

Telekom has compiled a migration guide with detailed information on the hypervisor changeover. The guide explains step by step what users need to consider when migrating Linux systems and Windows machines. In addition, the guide offers suggestions for solving potential problems and explains how users can retain IP addresses and resources if necessary.

Deutsche Telekom will support companies in their switchover where required. If they have any questions, they can contact Telekom experts at any time on 0800 – 33 04477 for callers from Germany, on 00800 – 33 044770 for callers from other countries or by e-mail: service@open-telekom-cloud.com.

"With the KVM hypervisor, we are now fully committed to the more up-to-date virtualization solution," said Andreas Falkner, Vice President Open Telekom Cloud, "because KVM offers companies a high degree of flexibility, scalability and performance."   

By switching to KVM, Telekom will use a uniform hypervisor in the future and will rely on a mature and established system. Since 2007, the KVM hypervisor has been continuously enhanced and now supports various processors (CPUs) and operating systems (OS) – including Windows as a guest system. Because KVM is based on open source software, source codes can be adapted and performance and functionality specifications changed.

While the Linux kernel manages the file system, block storage and drivers, KVM provides administrators with an interface to set up KVM guests, i.e. KVM-based virtual machines. Once set up, these virtual machines are assigned virtual CPUs and I/O resources to allow file system and guest system interaction. In this way, each virtual machine becomes a Linux process and operates at near bare metal speed. 

KVM also stands out due to its high security standards. This is shown, among other things, by a security study by the German Federal Office for Information Security (BSI), which classifies KVM as the most relevant virtualization solution in the open source sector.

While a few years ago there was a discussion in the user community about whether Xen or KVM should be used, today the tide has turned. KVM has established itself as the standard on a broad basis, and countless providers and users are already using the hypervisor integrated in Linux.

"KVM is quick and easy to install, and switching from Xen to KVM is usually also straightforward. All companies need to do is shut down systems running on Xen-based flavors and restart them on the KVM flavor," says Clemens Hardewig, Vice President Open Telekom Cloud Delivery. "They then benefit from all the modern hypervisor’s advantages."