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Feature Name

Ksplice Uptrack rebootless kernel updates


Keep Fedora's kernel up-to-date without rebooting. This uses the Ksplice Uptrack service to update the running kernel in memory, boosting security, availability and convenience by making it possible to stay on top of important kernel updates without the disruption of a reboot.


  • Email:

Current status

  • Targeted release: Fedora 14
  • Last updated: July 20, 2010
  • Percentage of completion: 100%

Detailed Description

Ksplice Uptrack allows system administrators to update the running Linux kernel "rebootlessly," using technology first developed at the Massachusetts Institute of Technology. Fedora and other major Linux distributions generally ask their users to reboot roughly once a month to install a new kernel to fix security and reliability issues. Empirically, users rarely install such updates -- Ksplice has measured real-world compliance at about 20% -- and until a system can be updated, it remains vulnerable to security flaws. By allowing IT administrators to install kernel updates without downtime, Uptrack dramatically reduces the cost of system administration and, in practice, boosts adherence to security updates to greater than 95%.

Ksplice Inc. will supply rebootless versions of the kernel updates Fedora distributes. The service will be free of charge. The client software is licensed under the GNU General Public License, version 2.

Benefit to Fedora

Fedora will gain the capability to apply important kernel updates without the disruption and downtime of a reboot. This will boost the security and reliability of systems that choose to install such rebootless updates. Fedora will become the first Linux distribution to integrate rebootless updates into the distribution.


A package of client software conforming to the Fedora Packaging Guidelines has been submitted for review (

The service is already operational in a preview for Fedora 13, and will begin supplying Fedora 14's kernel updates as soon as the kernel stabilizes.

How To Test

The Uptrack service is currently available for testing on Fedora 13. To test, please install the ksplice-uptrack RPM on a Fedora 13 system running an old version of the kernel. The client software will alert the user that there are rebootless updates available and will prompt the user to install them. After installation, the "uptrack-show" command will show the patched CVEs, and exploits written against vulnerabilities patched by the updates will no longer work. There should be no visible disruption of the machine while updates are being installed. To keep compatibility with kernel modules and applications, the output of the uname() system call is not altered.

In addition to the Fedora Packaging Guidelines-compliant SRPM uploaded for review, an earlier binary package available for immediate installation and testing on Fedora 13 is available here:

User Experience

The client software installs a panel widget to alert the user of the availability of rebootless kernel updates, prompting them to install updates as soon as they are available. The Ksplice software suppresses Fedora's notification instructing the user to reboot after the on-disk kernel has been updated. Users will continue to update their kernels on-disk using the package manager, and will boot into the new kernel after a reboot.


No other packages depend on this package.

Contingency Plan

None necessary, revert to previous release behavior. Ksplice Uptrack is already available as a preview for Fedora 13.


Upstream documentation is here:

Release Notes

Rebootless kernel updates

Fedora 14 includes Ksplice Uptrack, a service for updating the Linux kernel without the disruption of a reboot. By installing "rebootless" kernel updates, Fedora users can keep up-to-date with security and reliability patches without shutting down their computers or compromising the availability of servers.

Comments and Discussion