Technology
Today, every mainstream operating system requires regular reboots in order
to be up to date and secure. Since reboots cause downtime and disruption,
people are forced into the uncomfortable dilemma of choosing between security
and convenience.
Any delay in patching software problems - even a delay of just a few days to
arrange for downtime - can have serious consequences. Within just six
days after the announcement of the Linux sys_prctl vulnerability, many
servers had been compromised, including an important server for the Debian
distribution.
Ksplice enables running systems to stay secure without the disruption of
rebooting. Specifically, Ksplice creates rebootless updates that are
based on traditional source code patches. These updates are as effective as
traditional updates, but they can be applied seamlessly, with no downtime.
Ksplice currently supports updating the Linux kernel, but the Ksplice
technology applies to any operating system or to user space applications.
The Ksplice software uses a source code patch and the source code of the
running kernel in order to determine how to apply the patch to the running
kernel. The running kernel does not need to have been prepared in advance in
any way, which means that Ksplice can bring any system up to date, even one
that was first booted many years ago.
The Ksplice software currently supports the x86-32, x86-64, and ARM
architectures. Ksplice has been tested on Linux kernel versions ranging from
2.6.8 to 2.6.31, and on many Linux distributions, including Debian, Ubuntu, Red
Hat Enterprise Linux, CentOS, Virtuozzo, Fedora, and Gentoo.
The full technical paper can be viewed in PDF format at
http://www.canadianwebhosting.com/ksplice.pdf