July 14, 2009, 9:30 am
Every enterprise wants to harden its servers and increase uptime, but security updates often require reboots. Companies that want to please their customers need a better way to apply software updates. One potential solution for Linux servers is Ksplice, which can seamlessly apply live updates while the system is running.
The underlying technology behind Ksplice is highly sophisticated. To generate a live update, it compares compiled object code from before and after a source patch is applied, a technique that the developers refer to as "pre-post differencing." They take advantage of the -ffunction-sections and -fdata-sections options of the C compiler to eliminate some variance between the pre- and post-object code.