diff --git a/pkg/kubelet/cm/container_manager.go b/pkg/kubelet/cm/container_manager.go index fb82e039366..70edb484109 100644 --- a/pkg/kubelet/cm/container_manager.go +++ b/pkg/kubelet/cm/container_manager.go @@ -46,7 +46,13 @@ import ( const ( // Warning message for the users still using cgroup v1 - CgroupV1MaintenanceModeWarning = "Cgroup v1 support is in maintenance mode, please migrate to Cgroup v2." + CgroupV1MaintenanceModeWarning = "cgroup v1 support is in maintenance mode, please migrate to cgroup v2" + + // Warning message for the users using cgroup v2 on kernel doesn't support root `cpu.stat`. + // `cpu.stat` was added to root cgroup in kernel 5.8. + // (ref: https://github.com/torvalds/linux/commit/936f2a70f2077f64fab1dcb3eca71879e82ecd3f) + CgroupV2KernelWarning = "cgroup v2 is being used on a kernel, which doesn't support root `cpu.stat`." + + "Kubelet will continue, but may experience instability or wrong behavior" ) type ActivePodsFunc func() []*v1.Pod diff --git a/pkg/kubelet/kubelet.go b/pkg/kubelet/kubelet.go index b5d0c68ebc4..df9a401b5c0 100644 --- a/pkg/kubelet/kubelet.go +++ b/pkg/kubelet/kubelet.go @@ -1645,7 +1645,9 @@ func (kl *Kubelet) Run(updates <-chan kubetypes.PodUpdate) { os.Exit(1) } - kl.warnCgroupV1Usage() + if err := kl.cgroupVersionCheck(); err != nil { + klog.V(2).InfoS("Warning: cgroup check", "error", err) + } // Start volume manager go kl.volumeManager.Run(ctx, kl.sourcesReady) @@ -3067,12 +3069,3 @@ func (kl *Kubelet) PrepareDynamicResources(ctx context.Context, pod *v1.Pod) err func (kl *Kubelet) UnprepareDynamicResources(ctx context.Context, pod *v1.Pod) error { return kl.containerManager.UnprepareDynamicResources(ctx, pod) } - -func (kl *Kubelet) warnCgroupV1Usage() { - cgroupVersion := kl.containerManager.GetNodeConfig().CgroupVersion - if cgroupVersion == 1 { - kl.recorder.Eventf(kl.nodeRef, v1.EventTypeWarning, events.CgroupV1, cm.CgroupV1MaintenanceModeWarning) - klog.V(2).InfoS("Warning: cgroup v1", "message", cm.CgroupV1MaintenanceModeWarning) - } - metrics.CgroupVersion.Set(float64(cgroupVersion)) -} diff --git a/pkg/kubelet/kubelet_linux.go b/pkg/kubelet/kubelet_linux.go new file mode 100644 index 00000000000..c1f82b1af69 --- /dev/null +++ b/pkg/kubelet/kubelet_linux.go @@ -0,0 +1,51 @@ +//go:build linux + +/* +Copyright 2024 The Kubernetes Authors. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +package kubelet + +import ( + "errors" + "fmt" + "os" + "path/filepath" + + v1 "k8s.io/api/core/v1" + "k8s.io/kubernetes/pkg/kubelet/cm" + "k8s.io/kubernetes/pkg/kubelet/cm/util" + "k8s.io/kubernetes/pkg/kubelet/events" + "k8s.io/kubernetes/pkg/kubelet/metrics" +) + +func (kl *Kubelet) cgroupVersionCheck() error { + cgroupVersion := kl.containerManager.GetNodeConfig().CgroupVersion + metrics.CgroupVersion.Set(float64(cgroupVersion)) + switch cgroupVersion { + case 1: + kl.recorder.Eventf(kl.nodeRef, v1.EventTypeWarning, events.CgroupV1, cm.CgroupV1MaintenanceModeWarning) + return errors.New(cm.CgroupV1MaintenanceModeWarning) + case 2: + cpustat := filepath.Join(util.CgroupRoot, "cpu.stat") + if _, err := os.Stat(cpustat); os.IsNotExist(err) { + // if `/sys/fs/cgroup/cpu.stat` does not exist, log a warning + return errors.New(cm.CgroupV2KernelWarning) + } + default: + return fmt.Errorf("unsupported cgroup version: %d", cgroupVersion) + } + return nil +} diff --git a/pkg/kubelet/kubelet_others.go b/pkg/kubelet/kubelet_others.go new file mode 100644 index 00000000000..0bd5a586981 --- /dev/null +++ b/pkg/kubelet/kubelet_others.go @@ -0,0 +1,25 @@ +//go:build !linux + +/* +Copyright 2024 The Kubernetes Authors. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +package kubelet + +// cgroupVersionCheck performs a version check for the cgroup. +// This method is not applicable for non-Linux operating systems. +func (kl *Kubelet) cgroupVersionCheck() error { + return nil +}