1 /* 2 Copyright 2017 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 api 18 19 import ( 20 "time" 21 22 "k8s.io/apimachinery/pkg/api/resource" 23 ) 24 25 // Signal defines a signal that can trigger eviction of pods on a node. 26 type Signal string 27 28 const ( 29 // SignalMemoryAvailable is memory available (i.e. capacity - workingSet), in bytes. 30 SignalMemoryAvailable Signal = "memory.available" 31 // SignalNodeFsAvailable is amount of storage available on filesystem that kubelet uses for volumes, daemon logs, etc. 32 SignalNodeFsAvailable Signal = "nodefs.available" 33 // SignalNodeFsInodesFree is amount of inodes available on filesystem that kubelet uses for volumes, daemon logs, etc. 34 SignalNodeFsInodesFree Signal = "nodefs.inodesFree" 35 // SignalImageFsAvailable is amount of storage available on filesystem that container runtime uses for storing images layers. 36 // If the container filesystem and image filesystem are not separate, 37 // than imagefs can store both image layers and writeable layers. 38 SignalImageFsAvailable Signal = "imagefs.available" 39 // SignalImageFsInodesFree is amount of inodes available on filesystem that container runtime uses for storing images layers. 40 // If the container filesystem and image filesystem are not separate, 41 // than imagefs can store both image layers and writeable layers. 42 SignalImageFsInodesFree Signal = "imagefs.inodesFree" 43 // SignalContainerFsAvailable is amount of storage available on filesystem that container runtime uses for container writable layers. 44 // In case of a single filesystem, containerfs=nodefs. 45 // In case of a image filesystem, containerfs=imagefs. 46 // We will override user settings and set to either imagefs or nodefs depending on configuration. 47 SignalContainerFsAvailable Signal = "containerfs.available" 48 // SignalContainerFsInodesFree is amount of inodes available on filesystem that container runtime uses for container writable layers. 49 // SignalContainerFsAvailable is amount of storage available on filesystem that container runtime uses for container writable layers. 50 // In case of a single filesystem, containerfs=nodefs. 51 // In case of a image filesystem, containerfs=imagefs. 52 // We will override user settings and set to either imagefs or nodefs depending on configuration. 53 SignalContainerFsInodesFree Signal = "containerfs.inodesFree" 54 // SignalAllocatableMemoryAvailable is amount of memory available for pod allocation (i.e. allocatable - workingSet (of pods), in bytes. 55 SignalAllocatableMemoryAvailable Signal = "allocatableMemory.available" 56 // SignalPIDAvailable is amount of PID available for pod allocation 57 SignalPIDAvailable Signal = "pid.available" 58 ) 59 60 // ThresholdOperator is the operator used to express a Threshold. 61 type ThresholdOperator string 62 63 const ( 64 // OpLessThan is the operator that expresses a less than operator. 65 OpLessThan ThresholdOperator = "LessThan" 66 ) 67 68 // OpForSignal maps Signals to ThresholdOperators. 69 // Today, the only supported operator is "LessThan". This may change in the future, 70 // for example if "consumed" (as opposed to "available") type signals are added. 71 // In both cases the directionality of the threshold is implicit to the signal type 72 // (for a given signal, the decision to evict will be made when crossing the threshold 73 // from either above or below, never both). There is thus no reason to expose the 74 // operator in the Kubelet's public API. Instead, we internally map signal types to operators. 75 var OpForSignal = map[Signal]ThresholdOperator{ 76 SignalMemoryAvailable: OpLessThan, 77 SignalNodeFsAvailable: OpLessThan, 78 SignalNodeFsInodesFree: OpLessThan, 79 SignalImageFsAvailable: OpLessThan, 80 SignalImageFsInodesFree: OpLessThan, 81 SignalContainerFsAvailable: OpLessThan, 82 SignalContainerFsInodesFree: OpLessThan, 83 SignalAllocatableMemoryAvailable: OpLessThan, 84 SignalPIDAvailable: OpLessThan, 85 } 86 87 // ThresholdValue is a value holder that abstracts literal versus percentage based quantity 88 type ThresholdValue struct { 89 // The following fields are exclusive. Only the topmost non-zero field is used. 90 91 // Quantity is a quantity associated with the signal that is evaluated against the specified operator. 92 Quantity *resource.Quantity 93 // Percentage represents the usage percentage over the total resource that is evaluated against the specified operator. 94 Percentage float32 95 } 96 97 // Threshold defines a metric for when eviction should occur. 98 type Threshold struct { 99 // Signal defines the entity that was measured. 100 Signal Signal 101 // Operator represents a relationship of a signal to a value. 102 Operator ThresholdOperator 103 // Value is the threshold the resource is evaluated against. 104 Value ThresholdValue 105 // GracePeriod represents the amount of time that a threshold must be met before eviction is triggered. 106 GracePeriod time.Duration 107 // MinReclaim represents the minimum amount of resource to reclaim if the threshold is met. 108 MinReclaim *ThresholdValue 109 } 110 111 // GetThresholdQuantity returns the expected quantity value for a thresholdValue 112 func GetThresholdQuantity(value ThresholdValue, capacity *resource.Quantity) *resource.Quantity { 113 if value.Quantity != nil { 114 res := value.Quantity.DeepCopy() 115 return &res 116 } 117 return resource.NewQuantity(int64(float64(capacity.Value())*float64(value.Percentage)), resource.BinarySI) 118 } 119