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Container Engine (KCE)
User Guide
Autoscaling
Configure Cron horizontal pod autoscaling
Last updated：2021-05-11 10:41:27
A Cron Horizontal Pod Autoscaler (CronHPA) regularly scales pod resources in a Kubernetes cluster based on Crontab. A CronHPA is applicable to the scale-out or scale-in of any resources, for example, Deployments and StatefulSets.
After you figure out the operating pattern of workloads during maintenance, you can configure a CronHPA for regular and automatic scale-out and scale-in to cope with expected business requirements.
A Kubernetes cluster is created in KCE, and the cluster is running properly. For more information, see Create a cluster.
cron-hpa.yaml file.$ kubectl apply -f cron-hpa.yamlcron-hpa.yaml file is as follows:apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
creationTimestamp: null
labels:
controller-tools.k8s.io: "1.0"
name: cronhorizontalpodautoscalers.autoscaling.kce.ksyun.com
spec:
group: autoscaling.kce.ksyun.com
names:
kind: CronHorizontalPodAutoscaler
plural: cronhorizontalpodautoscalers
shortNames:
- cronhpa
scope: Namespaced
validation:
openAPIV3Schema:
properties:
apiVersion:
description: 'APIVersion defines the versioned schema of this representation
of an object. Servers should convert recognized schemas to the latest
internal value, and may reject unrecognized values. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#resources'
type: string
kind:
description: 'Kind is a string value representing the REST resource this
object represents. Servers may infer this from the endpoint the client
submits requests to. Cannot be updated. In CamelCase. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#types-kinds'
type: string
metadata:
type: object
spec:
properties:
jobs:
items:
properties:
name:
type: string
schedule:
type: string
targetSize:
format: int32
type: integer
required:
- name
- schedule
- targetSize
type: object
type: array
scaleTargetRef:
description: 'INSERT ADDITIONAL SPEC FIELDS - desired state of cluster
Important: Run "make" to regenerate code after modifying this file'
properties:
apiVersion:
type: string
kind:
type: string
name:
type: string
required:
- apiVersion
- kind
- name
type: object
required:
- scaleTargetRef
- jobs
type: object
status:
properties:
conditions:
description: 'INSERT ADDITIONAL STATUS FIELD - define observed state
of cluster Important: Run "make" to regenerate code after modifying
this file'
items:
properties:
jobId:
type: string
lastProbeTime:
format: date-time
type: string
message:
description: Human readable message indicating details about last
transition.
type: string
name:
description: Type of job condition, Complete or Failed.
type: string
schedule:
type: string
state:
type: string
required:
- name
- jobId
- schedule
- state
- lastProbeTime
- message
type: object
type: array
required:
- conditions
type: object
version: v1beta1
status:
acceptedNames:
kind: ""
plural: ""
conditions: []
storedVersions: []
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: kubernetes-cronhpa-controller-role
rules:
- apiGroups: [""]
resources: ["*"]
verbs:
- get
- list
- watch
- update
- apiGroups:
- extensions
resources: ["*"]
verbs:
- get
- list
- watch
- update
- apiGroups:
- apps
resources: ["*"]
verbs:
- get
- list
- watch
- update
- apiGroups: [""]
resources: ["events"]
verbs:
- get
- list
- watch
- create
- update
- patch
- apiGroups: [""]
resources: ["configmaps"]
verbs:
- get
- create
- update
- apiGroups:
- autoscaling.kce.ksyun.com
resources:
- cronhorizontalpodautoscalers
verbs:
- get
- list
- watch
- create
- update
- patch
- apiGroups:
- autoscaling
resources:
- horizontalpodautoscalers
verbs:
- get
- list
- watch
- create
- update
- patch
- delete
- apiGroups:
- admissionregistration.k8s.io
resources:
- mutatingwebhookconfigurations
- validatingwebhookconfigurations
verbs:
- get
- list
- watch
- create
- update
- patch
- delete
- apiGroups:
- apps.kruise.io
resources:
- statefulsets/scale
- uniteddeployments/scale
- clonesets/scale
verbs:
- get
- list
- watch
- update
- patch
- apiGroups:
- autoscaling.kce.ksyun.com
resources:
- elasticworkloads/scale
verbs:
- get
- list
- watch
- update
- patch
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: kubernetes-cronhpa-controller
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
creationTimestamp: null
name: kubernetes-cronhpa-controller-rolebinding
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: kubernetes-cronhpa-controller-role
subjects:
- kind: ServiceAccount
name: kubernetes-cronhpa-controller
namespace: kube-system
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: kubernetes-cronhpa-controller
namespace: kube-system
labels:
app: kubernetes-cronhpa-controller
controller-tools.k8s.io: "2.0"
spec:
replicas: 1 # The default is primary and standby mode (currently cold standby)
selector:
matchLabels:
app: kubernetes-cronhpa-controller
controller-tools.k8s.io: "2.0"
template:
metadata:
labels:
app: kubernetes-cronhpa-controller
controller-tools.k8s.io: "2.0"
spec:
containers:
- image: hub.kce.ksyun.com/ksyun/kubernetes-cronhpa-controller:v1.0.0
imagePullPolicy: Always
name: kubernetes-cronhpa-controller
env:
- name: TZ
value: "Asia/Shanghai"
resources:
limits:
cpu: 100m
memory: 100Mi
requests:
cpu: 100m
memory: 100Mi
serviceAccount: kubernetes-cronhpa-controller
# Check whether the custom resource is installed.
$ kubectl api-resources | grep cronhpa
cronhorizontalpodautoscalers cronhpa autoscaling.kce.ksyun.com true CronHorizontalPodAutoscaler
# Check whether the CronHPA Controller is installed.
$ kubectl get deploy kubernetes-cronhpa-controller -n kube-system
NAME READY UP-TO-DATE AVAILABLE AGE
kubernetes-cronhpa-controller 1/1 1 1 4m11sThis section describes how to deploy and test a CronHPA after the CronHPA plug-in is installed.
$ kubectl apply -f cronhpa-example.yamlcronhpa-example.yaml file is as follows:---
apiVersion: apps/v1 # for versions before 1.8.0 use apps/v1beta1
kind: Deployment
metadata:
name: nginx-deployment-basic
labels:
app: nginx
spec:
replicas: 2
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.7.9 # replace it with your exactly <image_name:tags>
ports:
- containerPort: 80
---
apiVersion: autoscaling.kce.ksyun.com/v1beta1
kind: CronHorizontalPodAutoscaler
metadata:
labels:
controller-tools.k8s.io: "1.0"
name: cronhpa-sample
spec:
scaleTargetRef:
apiVersion: apps/v1beta2
kind: Deployment
name: nginx-deployment-basic
excludeDates:
- "* * * 15 11 *" # exclude November 15th
- "* * * * * 5" # exclude every Friday
jobs:
- name: "scale-down"
schedule: "30 */1 * * * *" # Indicates that the number of replicas for the Deployment nginx-deployment-basic is adjusted to 1 at the 30th second of every minute.
targetSize: 1
- name: "scale-up"
schedule: "0 */1 * * * *" # Indicates that the number of replicas for the Deployment nginx-deployment-basic is adjusted to 3 at the 0th second of every minute.
targetSize: 3
| Field | Description | Remarks | ||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| scaleTargetRef | The scaling object. A CronHPA can scale sub-resources of the object as long as the object supports sub-resource scaling. | A CronHPA can also adjust the number of pods. To ensure stability, the system uses the larger one of the expected number of replicas specified in the CronHPA configuration and that specified in the HPA configuration as the final value for scaling. | ||||||||||||||||||||||||||||
| excludeDates | The date array. The job is skipped on the dates specified by this field. | This field is specified by day. | ||||||||||||||||||||||||||||
| jobs | The CronHPA jobs. You can configure multiple CronHPA jobs in one spec. The following fields are configured for each CronHPA job: - name: the name of the job, which must be unique in the CronHPA configuration. - schedule: the scaling schedule, which is similar to Crontab. - targetSize: the expected number of pods at the scheduled time. - runOnce: specifies whether the job runs only once. If this field is set to true, the job runs only once and then exits. | The Cron expression contains the following fields:
|
$ kubectl get cronhpa
NAME AGE
cronhpa-sample 15s$ kubectl describe cronhpa cronhpa-sample
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Succeed 8m31s cron-horizontal-pod-autoscaler cron hpa job scale-down executed successfully. current replicas:2, desired replicas:1.
Normal Succeed 31s (x8 over 7m31s) cron-horizontal-pod-autoscaler cron hpa job scale-down executed successfully. current replicas:3, desired replicas:1.
Normal Succeed 1s (x9 over 8m1s) cron-horizontal-pod-autoscaler cron hpa job scale-up executed successfully. current replicas:1, desired replicas:3.$ kubectl get deploy nginx-deployment-basic -w
NAME READY UP-TO-DATE AVAILABLE AGE
nginx-deployment-basic 1/1 1 1 3m31s
nginx-deployment-basic 1/3 1 1 3m48s
nginx-deployment-basic 1/3 1 1 3m48s
nginx-deployment-basic 1/3 3 1 3m48s
nginx-deployment-basic 2/3 3 2 3m50s
nginx-deployment-basic 3/3 3 3 3m50s
nginx-deployment-basic 3/1 3 3 4m18s
nginx-deployment-basic 3/1 3 3 4m18s
nginx-deployment-basic 1/1 1 1 4m18s
nginx-deployment-basic 1/3 1 1 4m48s
nginx-deployment-basic 1/3 1 1 4m48s
nginx-deployment-basic 1/3 1 1 4m48s
nginx-deployment-basic 1/3 3 1 4m48s
nginx-deployment-basic 2/3 3 2 4m49s
nginx-deployment-basic 3/3 3 3 4m49sPure Mode