In a bold move, the Canonical Kernel Team (CKT) has announced a significant shift in selecting Linux kernel versions for upcoming Ubuntu releases. The team aims to align more closely with the latest developments from the upstream Linux kernel.
This change is intended to provide Ubuntu users with the most recent kernel features and enhancements, even if this means incorporating Release Candidate versions at the time of the Ubuntu release freeze.
Historically, the kernel selection process for Ubuntu releases was a careful balance between the independent release schedules of the upstream Linux kernel and Ubuntu’s own rigid release timelines.
The upstream Linux kernel, developed by the global Linux community, follows a loosely time-based model, releasing new versions approximately every two to three months depending on readiness and stability.
In contrast, Ubuntu schedules its releases far in advance, adhering to a strict six-month cycle that rarely shifts, regardless of external factors.
This discrepancy in release philosophies has occasionally led to challenges in synchronizing new kernel releases with Ubuntu’s fixed release dates.
Typically, the CKT would wait about a month after an upstream release before deeming it stable enough for inclusion in Ubuntu to ensure reliability and compatibility with Ubuntuโs broad array of hardware and software ecosystems. But all that is about to change.
Ubuntu: The New Approach to Kernel Releases
With the latest policy update, the CKT is pivoting to a more aggressive stance. Ubuntu will now ship the most recent version of the upstream Linux kernel, available at the Ubuntu release freeze date.
This includes kernels even still in the RC phase, reflecting a bold move to offer cutting-edge technology at the risk of initial instability.
However, this approach has risks, as tighter integration timelines could potentially lead to stability and compatibility issues. The new strategy will categorize upcoming Ubuntu releases into different states based on the kernel’s development stage at the time of the feature freeze:
- Tight Release: The upstream kernel is near its final release version during Ubuntu’s feature freeze.
- Unstable Release: During the feature freeze, the upstream kernel was still in early RC stages, indicating a higher likelihood of significant changes and instability.
To manage the inherent risks of this new approach, Ubuntu plans to utilize what it calls a “Bridge Kernel” in certain scenarios.
This is essentially the last stable kernel release, which will be used temporarily when newer kernel versions are expected to be unstable or lack support for critical dependent components like NVIDIA drivers or the ZFS file system.
For more information on the new Ubuntu kernel strategy, visit the official announcement.
