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From Comparison to Choice: kpatch vs Ksplice and the Advantages of Switching to KernelCare
Artem Karasev
May 6, 2024 - Senior Product Marketing Manager
- Live patching enables crucial Linux security updates without reboots, eliminating downtime.
- Various live patching tools like kpatch, Ksplice, and KernelCare cater to different Linux distributions and needs.
- KernelCare stands out providing comprehensive live patching for diverse Linux environments.
Adopting live patching is considered a cybersecurity best practice, offering an optimal solution for deploying security updates on Linux systems. This method enables the application of crucial security patches to address kernel vulnerabilities without requiring system reboots, thereby eliminating the need for scheduled downtime and ensuring consistent security and uninterrupted system operations.
Among the leading options, kpatch from Red Hat and Ksplice from Oracle each offer distinct features. Despite this, KernelCare, offered by TuxCare, with its growing base of over 2300 enterprise customers across various industries, continues to gain popularity. This article will explore the pros and cons of kpatch and Ksplice and discuss why enterprise organizations worldwide are increasingly opting for KernelCare in the ongoing kpatch vs Ksplice debate.
kpatch vs Ksplice in Multi-distro Environments
Ksplice, created by four MIT students in 2009 and later acquired by Oracle in 2011, alongside kpatch, introduced by Red Hat in 2014, are both highly regarded for their effective live Linux kernel patching. However, they share a common limitation: ready-to-apply live patches are available exclusively for their respective distributions and a limited selection of just a few other Linux distributions.
Following Oracle’s acquisition, Ksplice usage has been restricted to customers with an active Oracle Linux Premier Support subscription ($1399/CPU pair per year), limiting its application to Oracle Linux, Red Hat, and Ubuntu systems. At the same time, if the system is running Red Hat Enterprise Linux, customers are required to switch to an Oracle-provided Red Hat Compatible Kernel (RHCK) and reboot the system before they can apply Ksplice patches.
Similarly, kpatch is developed and maintained by Red Hat, specifically for users of Red Hat Enterprise Linux (RHEL) having active Red Hat subscriptions (starting at $879/ server per year). Although kpatch technically supports Ubuntu, Debian, and Gentoo, customers who wish to use it with these distributions must manually create the necessary live patches using the patching tools themselves. It’s important to note that creating live patches most often isn’t an easy process and requires specific expertise. It can have some major pitfalls if you’re not careful.
Given that organizations often deploy multiple Linux distributions across their environments – a fact supported by our research – tools restricted to single distributions or a small group of distributions may not fully meet the needs of managing an organization’s diverse systems.
In this round, Ksplice wins by providing live patches to slightly more distributions than kpatch.
Vulnerability Coverage
Another critical aspect to consider is how kpatch and Ksplice handle vulnerability coverage. Both tools address only high and critical CVEs (Common Vulnerabilities and Exposures). However, Red Hat and Oracle can adjust the original severity scores of these CVEs assigned by the National Vulnerability Database based on their proprietary criteria. This means kpatch and Ksplice may not address all vulnerabilities considered high and critical by external rating systems. Moreover, even among the vulnerabilities that Red Hat continues to classify as high and critical, their documentation specifies that not all are guaranteed to be patched using their live patching service.
This selective approach is critical, especially in environments with specific security needs. Some less critical vulnerabilities adjusted by these vendors might still pose significant risks in certain contexts. Therefore, the effectiveness of a live patching tool also depends on its ability to adapt to an organization’s specific security priorities.
This round results in a draw, as each tool’s effectiveness depends on the organization’s unique security priorities.
Patch Rollback Feature
If a patch doesn’t perform as expected, it’s nice to know you can easily revert to a previous kernel state if you need to. This can be particularly useful in situations where the patch has a considerable negative impact on a system’s performance (e.g., Spectre/Meltdown fixes) and other mitigations are available.
System admins appreciate the flexibility that Ksplice offers, allowing them to instantly reverse kernel updates without needing a system reboot. On the other hand, kpatch, according to the documentation, “does not support reverting live patches without rebooting your system.” This may cause costly service disruptions, compromising the main benefit of live patching.
Ksplice takes the lead in this kpatch vs Ksplice round due to its ability to allow any patch to be rolled back without a reboot, should a system administrator choose to.
Kernel Patching Lifetime: A Crucial Factor in the kpatch vs Ksplice Contest
As we evaluate the broader implications of choosing between kpatch and Ksplice, the longevity of patch support is also a crucial factor. Red Hat stops providing live patches for its kernels six months after their release. Customers who want to continue receiving kpatch updates must upgrade their kernel and schedule at least two reboots annually. This necessitates aligning their maintenance schedules with Red Hat’s release timeline.
In contrast, Ksplice provides live patches with a practically unlimited kernel patching lifetime, providing sustained security without the tied constraints of the operating system release schedule, giving it an edge in this round.
The overall contest between kpatch and Ksplice results in a win for Ksplice, though this process highlights that – while each has its strengths – limitations persist. This brings us to an innovative solution that addresses these limitations comprehensively.
KernelCare Takes Live Patching to New Heights
KernelCare stands out not just as another option but as a superior alternative in the kpatch vs Ksplice competition. It offers broad distribution support, covering over 60 different distribution versions, including RHEL, Debian, Oracle Linux, AlmaLinux, Amazon Linux, Rocky Linux, and more. This extensive coverage makes it a comprehensive solution, effectively eliminating the need for multiple patching systems across diverse Linux-based environments.
The product delivers live patches for every vulnerability that the vendors addressed with traditional patches while also addressing those vulnerabilities that vendors did not patch but that are still significant, impacting numerous systems, or known to be exploited in the wild.
Moreover, like Ksplice, KernelCare allows any patch to be rolled back by running a special command that does not require rebooting your system, helping to prevent potentially costly disruptions. Additionally, mirroring Ksplice’s advantage, KernelCare offers an unlimited patching lifetime, thus combining the best of both worlds – stability and longevity.
And, last but not least. If you opted for KernelCare, you’ll be looking at budget-friendly pricing that comes down to less than $40/server per year!
Organizations considering their options in live patching should weigh these benefits carefully. KernelCare provides a compelling case for those seeking minimal downtime and comprehensive vulnerability coverage across various Linux distributions. If you’re still unsure, why not give it a try? KernelCare is available as a 30-day free trial – with full functionality and no commitment to buy.
