k8s.io/kubernetes@v1.31.0-alpha.0.0.20240520171757-56147500dadc/cmd/kubeadm/app/componentconfigs/kubelet_unix.go (about)

     1  //go:build !windows
     2  // +build !windows
     3  
     4  /*
     5  Copyright 2021 The Kubernetes Authors.
     6  
     7  Licensed under the Apache License, Version 2.0 (the "License");
     8  you may not use this file except in compliance with the License.
     9  You may obtain a copy of the License at
    10  
    11      http://www.apache.org/licenses/LICENSE-2.0
    12  
    13  Unless required by applicable law or agreed to in writing, software
    14  distributed under the License is distributed on an "AS IS" BASIS,
    15  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    16  See the License for the specific language governing permissions and
    17  limitations under the License.
    18  */
    19  
    20  package componentconfigs
    21  
    22  import (
    23  	"k8s.io/klog/v2"
    24  	kubeletconfig "k8s.io/kubelet/config/v1beta1"
    25  	"k8s.io/utils/ptr"
    26  
    27  	"k8s.io/kubernetes/cmd/kubeadm/app/util/initsystem"
    28  )
    29  
    30  // Mutate allows applying pre-defined modifications to the config before it's marshaled.
    31  func (kc *kubeletConfig) Mutate() error {
    32  	if err := mutateResolverConfig(&kc.config, isServiceActive); err != nil {
    33  		return err
    34  	}
    35  	return nil
    36  }
    37  
    38  // mutateResolverConfig mutates the ResolverConfig in the kubeletConfig dynamically.
    39  func mutateResolverConfig(cfg *kubeletconfig.KubeletConfiguration, isServiceActiveFunc func(string) (bool, error)) error {
    40  	ok, err := isServiceActiveFunc("systemd-resolved")
    41  	if err != nil {
    42  		klog.Warningf("cannot determine if systemd-resolved is active: %v", err)
    43  	}
    44  	if ok {
    45  		if cfg.ResolverConfig == nil {
    46  			cfg.ResolverConfig = ptr.To(kubeletSystemdResolverConfig)
    47  		} else if *cfg.ResolverConfig != kubeletSystemdResolverConfig {
    48  			warnDefaultComponentConfigValue("KubeletConfiguration", "resolvConf",
    49  				kubeletSystemdResolverConfig, *cfg.ResolverConfig)
    50  		}
    51  
    52  	}
    53  	return nil
    54  }
    55  
    56  // isServiceActive checks whether the given service exists and is running
    57  func isServiceActive(name string) (bool, error) {
    58  	initSystem, err := initsystem.GetInitSystem()
    59  	if err != nil {
    60  		return false, err
    61  	}
    62  	return initSystem.ServiceIsActive(name), nil
    63  }