Amazon Web Services today said it has found a way to avoid rebooting its cloud servers to patch against vulnerabilities in the underlying Xen virtualisation layer.

The company earlier believed it would have to reboot around ten percent of its elastic compute cloud (EC2) instances, throughout this week in regions around the world.
Now however AWS said it will be able to live update most of its older hardware, in order to fix the Xen flaw.
Thanks to the live update, less then a tenth of a percent of total EC2 instances require rebooting, AWS said.
Cloud provider Rackspace's systems are also affected by the Xen hypervisor vulnerabilities, and will reboot its Sydney infrastructure on March 5 between 1am and 5am AEDST.
Details of the Xen vulnerabilities are yet to be published which is in accordance with the organisation's security policy of preannouncing to large customers providing them time to patch before the flaws become common knowledge.