KernelCare is a service that provides important updates for your running kernel, removing the need to reboot your server.
The kernel is the central module of an operating system (OS). It is the part of the operating system that loads first, and it remains in main memory. Because it stays in memory, it is important for the kernel to be as small as possible while still providing all the essential services required by other parts of the operating system and applications.
Keeping the kernels updated manually can take hours, will cause server downtime and stressing system admins and clients alike. A server has to be rebooted after applying any kernel updates or patches and such reboots usually have to be done during off-peak hours.
This is where KernelCare comes in. It provides a service that will patch security vulnerabilities inside the running kernel – without any downtime or service interruption. With Kernel Care installed on your server, security updates are applied automatically (every 4 hours) on a running server (live server), without downtime, removing the need to reboot the server.
KernelCare supports CentOS and RHEL 5, 6 and 7, CloudLinux 5 and 6, OpenVZ, Virtuozzo, PCS and Debian 6 for x86_64 unmodified kernels. Debian 7, Ubuntu and other kernels will follow. You can find complete list, as well as patches available for each kernel here: http://patches.kernelcare.com/