pod_update.go

Documentation: k8s.io/kubernetes/pkg/kubelet/types

     1  /*
     2  Copyright 2014 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 types
    18  
    19  import (
    20  	"fmt"
    21  
    22  	v1 "k8s.io/api/core/v1"
    23  	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
    24  	"k8s.io/kubernetes/pkg/apis/scheduling"
    25  )
    26  
    27  // Annotation keys for annotations used in this package.
    28  const (
    29  	ConfigSourceAnnotationKey    = "kubernetes.io/config.source"
    30  	ConfigMirrorAnnotationKey    = v1.MirrorPodAnnotationKey
    31  	ConfigFirstSeenAnnotationKey = "kubernetes.io/config.seen"
    32  	ConfigHashAnnotationKey      = "kubernetes.io/config.hash"
    33  )
    34  
    35  // PodOperation defines what changes will be made on a pod configuration.
    36  type PodOperation int
    37  
    38  // These constants identify the PodOperations that can be made on a pod configuration.
    39  const (
    40  	// SET is the current pod configuration.
    41  	SET PodOperation = iota
    42  	// ADD signifies pods that are new to this source.
    43  	ADD
    44  	// DELETE signifies pods that are gracefully deleted from this source.
    45  	DELETE
    46  	// REMOVE signifies pods that have been removed from this source.
    47  	REMOVE
    48  	// UPDATE signifies pods have been updated in this source.
    49  	UPDATE
    50  	// RECONCILE signifies pods that have unexpected status in this source,
    51  	// kubelet should reconcile status with this source.
    52  	RECONCILE
    53  )
    54  
    55  // These constants identify the sources of pods.
    56  const (
    57  	// Filesource idenitified updates from a file.
    58  	FileSource = "file"
    59  	// HTTPSource identifies updates from querying a web page.
    60  	HTTPSource = "http"
    61  	// ApiserverSource identifies updates from Kubernetes API Server.
    62  	ApiserverSource = "api"
    63  	// AllSource identifies updates from all sources.
    64  	AllSource = "*"
    65  )
    66  
    67  // NamespaceDefault is a string representing the default namespace.
    68  const NamespaceDefault = metav1.NamespaceDefault
    69  
    70  // PodUpdate defines an operation sent on the channel. You can add or remove single services by
    71  // sending an array of size one and Op == ADD|REMOVE (with REMOVE, only the ID is required).
    72  // For setting the state of the system to a given state for this source configuration, set
    73  // Pods as desired and Op to SET, which will reset the system state to that specified in this
    74  // operation for this source channel. To remove all pods, set Pods to empty object and Op to SET.
    75  //
    76  // Additionally, Pods should never be nil - it should always point to an empty slice. While
    77  // functionally similar, this helps our unit tests properly check that the correct PodUpdates
    78  // are generated.
    79  type PodUpdate struct {
    80  	Pods   []*v1.Pod
    81  	Op     PodOperation
    82  	Source string
    83  }
    84  
    85  // GetValidatedSources gets all validated sources from the specified sources.
    86  func GetValidatedSources(sources []string) ([]string, error) {
    87  	validated := make([]string, 0, len(sources))
    88  	for _, source := range sources {
    89  		switch source {
    90  		case AllSource:
    91  			return []string{FileSource, HTTPSource, ApiserverSource}, nil
    92  		case FileSource, HTTPSource, ApiserverSource:
    93  			validated = append(validated, source)
    94  		case "":
    95  			// Skip
    96  		default:
    97  			return []string{}, fmt.Errorf("unknown pod source %q", source)
    98  		}
    99  	}
   100  	return validated, nil
   101  }
   102  
   103  // GetPodSource returns the source of the pod based on the annotation.
   104  func GetPodSource(pod *v1.Pod) (string, error) {
   105  	if pod.Annotations != nil {
   106  		if source, ok := pod.Annotations[ConfigSourceAnnotationKey]; ok {
   107  			return source, nil
   108  		}
   109  	}
   110  	return "", fmt.Errorf("cannot get source of pod %q", pod.UID)
   111  }
   112  
   113  // SyncPodType classifies pod updates, eg: create, update.
   114  type SyncPodType int
   115  
   116  const (
   117  	// SyncPodSync is when the pod is synced to ensure desired state
   118  	SyncPodSync SyncPodType = iota
   119  	// SyncPodUpdate is when the pod is updated from source
   120  	SyncPodUpdate
   121  	// SyncPodCreate is when the pod is created from source
   122  	SyncPodCreate
   123  	// SyncPodKill is when the pod should have no running containers. A pod stopped in this way could be
   124  	// restarted in the future due config changes.
   125  	SyncPodKill
   126  )
   127  
   128  func (sp SyncPodType) String() string {
   129  	switch sp {
   130  	case SyncPodCreate:
   131  		return "create"
   132  	case SyncPodUpdate:
   133  		return "update"
   134  	case SyncPodSync:
   135  		return "sync"
   136  	case SyncPodKill:
   137  		return "kill"
   138  	default:
   139  		return "unknown"
   140  	}
   141  }
   142  
   143  // IsMirrorPod returns true if the passed Pod is a Mirror Pod.
   144  func IsMirrorPod(pod *v1.Pod) bool {
   145  	if pod.Annotations == nil {
   146  		return false
   147  	}
   148  	_, ok := pod.Annotations[ConfigMirrorAnnotationKey]
   149  	return ok
   150  }
   151  
   152  // IsStaticPod returns true if the pod is a static pod.
   153  func IsStaticPod(pod *v1.Pod) bool {
   154  	source, err := GetPodSource(pod)
   155  	return err == nil && source != ApiserverSource
   156  }
   157  
   158  // IsCriticalPod returns true if pod's priority is greater than or equal to SystemCriticalPriority.
   159  func IsCriticalPod(pod *v1.Pod) bool {
   160  	if IsStaticPod(pod) {
   161  		return true
   162  	}
   163  	if IsMirrorPod(pod) {
   164  		return true
   165  	}
   166  	if pod.Spec.Priority != nil && IsCriticalPodBasedOnPriority(*pod.Spec.Priority) {
   167  		return true
   168  	}
   169  	return false
   170  }
   171  
   172  // Preemptable returns true if preemptor pod can preempt preemptee pod
   173  // if preemptee is not critical or if preemptor's priority is greater than preemptee's priority
   174  func Preemptable(preemptor, preemptee *v1.Pod) bool {
   175  	if IsCriticalPod(preemptor) && !IsCriticalPod(preemptee) {
   176  		return true
   177  	}
   178  	if (preemptor != nil && preemptor.Spec.Priority != nil) &&
   179  		(preemptee != nil && preemptee.Spec.Priority != nil) {
   180  		return *(preemptor.Spec.Priority) > *(preemptee.Spec.Priority)
   181  	}
   182  
   183  	return false
   184  }
   185  
   186  // IsCriticalPodBasedOnPriority checks if the given pod is a critical pod based on priority resolved from pod Spec.
   187  func IsCriticalPodBasedOnPriority(priority int32) bool {
   188  	return priority >= scheduling.SystemCriticalPriority
   189  }
   190  
   191  // IsNodeCriticalPod checks if the given pod is a system-node-critical
   192  func IsNodeCriticalPod(pod *v1.Pod) bool {
   193  	return IsCriticalPod(pod) && (pod.Spec.PriorityClassName == scheduling.SystemNodeCritical)
   194  }
   195  
   196  // IsRestartableInitContainer returns true if the initContainer has
   197  // ContainerRestartPolicyAlways.
   198  func IsRestartableInitContainer(initContainer *v1.Container) bool {
   199  	if initContainer.RestartPolicy == nil {
   200  		return false
   201  	}
   202  
   203  	return *initContainer.RestartPolicy == v1.ContainerRestartPolicyAlways
   204  }
   205
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