pod_container_deletor.go

Documentation: k8s.io/kubernetes/pkg/kubelet

     1  /*
     2  Copyright 2016 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package kubelet
    18  
    19  import (
    20  	"context"
    21  	"sort"
    22  
    23  	"k8s.io/apimachinery/pkg/util/wait"
    24  	"k8s.io/klog/v2"
    25  	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
    26  )
    27  
    28  const (
    29  	// The limit on the number of buffered container deletion requests
    30  	// This number is a bit arbitrary and may be adjusted in the future.
    31  	containerDeletorBufferLimit = 50
    32  )
    33  
    34  type containerStatusbyCreatedList []*kubecontainer.Status
    35  
    36  type podContainerDeletor struct {
    37  	worker           chan<- kubecontainer.ContainerID
    38  	containersToKeep int
    39  }
    40  
    41  func (a containerStatusbyCreatedList) Len() int      { return len(a) }
    42  func (a containerStatusbyCreatedList) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
    43  func (a containerStatusbyCreatedList) Less(i, j int) bool {
    44  	return a[i].CreatedAt.After(a[j].CreatedAt)
    45  }
    46  
    47  func newPodContainerDeletor(runtime kubecontainer.Runtime, containersToKeep int) *podContainerDeletor {
    48  	buffer := make(chan kubecontainer.ContainerID, containerDeletorBufferLimit)
    49  	go wait.Until(func() {
    50  		for {
    51  			id := <-buffer
    52  			if err := runtime.DeleteContainer(context.Background(), id); err != nil {
    53  				klog.InfoS("DeleteContainer returned error", "containerID", id, "err", err)
    54  			}
    55  		}
    56  	}, 0, wait.NeverStop)
    57  
    58  	return &podContainerDeletor{
    59  		worker:           buffer,
    60  		containersToKeep: containersToKeep,
    61  	}
    62  }
    63  
    64  // getContainersToDeleteInPod returns the exited containers in a pod whose name matches the name inferred from filterContainerId (if not empty), ordered by the creation time from the latest to the earliest.
    65  // If filterContainerID is empty, all dead containers in the pod are returned.
    66  func getContainersToDeleteInPod(filterContainerID string, podStatus *kubecontainer.PodStatus, containersToKeep int) containerStatusbyCreatedList {
    67  	matchedContainer := func(filterContainerId string, podStatus *kubecontainer.PodStatus) *kubecontainer.Status {
    68  		if filterContainerId == "" {
    69  			return nil
    70  		}
    71  		for _, containerStatus := range podStatus.ContainerStatuses {
    72  			if containerStatus.ID.ID == filterContainerId {
    73  				return containerStatus
    74  			}
    75  		}
    76  		return nil
    77  	}(filterContainerID, podStatus)
    78  
    79  	if filterContainerID != "" && matchedContainer == nil {
    80  		klog.InfoS("Container not found in pod's containers", "containerID", filterContainerID)
    81  		return containerStatusbyCreatedList{}
    82  	}
    83  
    84  	// Find the exited containers whose name matches the name of the container with id being filterContainerId
    85  	var candidates containerStatusbyCreatedList
    86  	for _, containerStatus := range podStatus.ContainerStatuses {
    87  		if containerStatus.State != kubecontainer.ContainerStateExited {
    88  			continue
    89  		}
    90  		if matchedContainer == nil || matchedContainer.Name == containerStatus.Name {
    91  			candidates = append(candidates, containerStatus)
    92  		}
    93  	}
    94  
    95  	if len(candidates) <= containersToKeep {
    96  		return containerStatusbyCreatedList{}
    97  	}
    98  	sort.Sort(candidates)
    99  	return candidates[containersToKeep:]
   100  }
   101  
   102  // deleteContainersInPod issues container deletion requests for containers selected by getContainersToDeleteInPod.
   103  func (p *podContainerDeletor) deleteContainersInPod(filterContainerID string, podStatus *kubecontainer.PodStatus, removeAll bool) {
   104  	containersToKeep := p.containersToKeep
   105  	if removeAll {
   106  		containersToKeep = 0
   107  		filterContainerID = ""
   108  	}
   109  
   110  	for _, candidate := range getContainersToDeleteInPod(filterContainerID, podStatus, containersToKeep) {
   111  		select {
   112  		case p.worker <- candidate.ID:
   113  		default:
   114  			klog.InfoS("Failed to issue the request to remove container", "containerID", candidate.ID)
   115  		}
   116  	}
   117  }
   118
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