Kernelsharing

Kernelsharing refers to the practice of running multiple workloads on a single kernel instance rather than distributing separate kernels to each workload. In modern operating systems and container platforms, kernelsharing enables processes, containers, and virtual environments to share the host kernel, reducing memory usage and simplifying system updates. The approach contrasts with traditional virtual machines, where each VM typically includes its own kernel.

Key mechanisms include Linux namespaces for process isolation (PID, IPC, mount, network), cgroups for resource control, and security modules such as SELinux or AppArmor. Container runtimes and orchestration platforms rely on these primitives to provide isolation while the kernel itself is shared. Some architectures also explore userspace kernel implementations to trade performance for stronger isolation, while others emphasize lightweight shared-kernel models via containerization and related experiments.

Advantages of kernelsharing include a reduced memory footprint, faster startup times, and easier maintenance since patches and updates apply to a single kernel. Risks involve a higher potential impact from a kernel fault or vulnerability, possible cross-workload interference, and the need for careful security configuration to maintain strong isolation between tenants or containers.

Kernelsharing is a central feature of modern containerization, particularly on Linux systems, where multiple containers commonly share the host kernel. It relates to broader concepts such as virtualization, container runtimes, and unikernel approaches, and it contrasts with models that provide per-virtual-machine or per-application kernels.