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By Zayden R., September 15, 2026
Kubernetes v1.37 promotes Memory QoS to Beta, activating it by default on Linux nodes with cgroup v2. Engineers can now configure memory behavior more precisely, enhancing container management.
Kubernetes v1.37 has taken a significant step by promoting Memory QoS to Beta status, with the feature now enabled by default. This update, detailed by Qi Wang and Sohan Kunkerkar from Red Hat, aims to refine container memory management on Linux nodes operating with cgroup v2. By using the memory controller, it provides better guidance to the kernel on handling container memory, which can be crucial for optimizing performance and resource allocation.
Originally introduced as an Alpha feature in Kubernetes v1.22, Memory QoS has seen substantial evolution. The v1.36 release expanded its capabilities with tiered memory reservation, and now v1.37 makes it more accessible by default. This is particularly beneficial for cluster operators who can now manage memory more effectively without manual configuration changes.
In practical terms, the feature's Beta status means that the MemoryQoS feature gate is automatically turned on in v1.37 kubelets. However, it's worth noting that the default kubelet configuration does not activate memory throttling or reservation unless explicitly set. This ensures that existing workloads remain unaffected by the upgrade unless operators choose to configure new settings. For instance, the memoryThrottlingFactor can be adjusted to enable memory.high throttling for Burstable and BestEffort containers, while memoryReservationPolicy can be set to TieredReservation for enhanced memory protection.
A significant change in v1.37 is the default setting of memoryThrottlingFactor to null, a shift from the previous default of 0.9 in Alpha releases. This adjustment prevents automatic memory.high settings that could inadvertently throttle workloads. For engineers managing clusters, this means that upgrading to v1.37 should not disrupt current operations unless they specifically configure these parameters.
Overall, the graduation of Memory QoS to Beta is a solid improvement for Kubernetes users, offering greater flexibility and control over memory management without introducing unexpected behavior changes. Engineers should review their kubelet configuration files to ensure they leverage these new capabilities effectively.