容器定时伸缩_弹性伸缩_Kubernetes集群用户指南_容器服务Kubernetes版

背景信息

kubernetes-cronhpa-controller是一个Kubernetes HPA controller，按照类似crontab的策略定时地对容器服务Kubernetes集群进行扩缩容。您可以把CronHorizontalPodAutoscaler（以下简称cronhpa）用在任何Kubernetes中定义的对象上，只要该对象支持scale子资源（如，Deployment和StatefulSet）的项目已在GitHub开源。

以下举例对cronhpa的各字段进行解释说明。

apiVersion: autoscaling.alibabacloud.com/v1beta1
kind: CronHorizontalPodAutoscaler
metadata:
  labels:
    controller-tools.k8s.io: "1.0"
  name: cronhpa-sample
  namespace: default 
spec:
   scaleTargetRef:
      apiVersion: apps/v1
      kind: Deployment
      name: nginx-deployment-basic
   excludeDates:
   # exclude November 15th
   - "* * * 15 11 *"
   # exclude every Friday 
   - "* * * * * 5"
   jobs:
   - name: "scale-down"
     schedule: "30 */1 * * * *"
     targetSize: 1
   - name: "scale-up"
     schedule: "0 */1 * * * *"
     targetSize: 3
     runOnce: true


字段	说明
scaleTargetRef	scaleTargetRef指定去扩缩容对象。如果对象支持scale子资源，cronhpa即可支持。
excludeDates	excludeDates是日期数组。当遇到符合excludeDates描述的日期时任务将会被跳过。说明最小单位为天。 `- "* * * * * "`表示-"Seconds Minutes Hours Day of month Month Day of week"。如您想在11月15日不运行任务，可像以下示例一样指定excludeDates。 `excludeDates: - " * * 15 11 *"`
jobs	支持在一个spec中设定多个cronhpa任务。每个cronhpa任务可以配置以下字段： name：它在一个cronhpa中应是唯一的，这样就可以通过name来区分不同的任务。 schedule：它的策略和crontab类似。kubernetes-cronhpa-controller使用了Golang库（go-cron）功能更强大的cron，它支持更多表示规则。创建时请严格按照以下格式说明进行设置，否则将导致创建失败。 cron表达式的格式如下： `Field name \| Mandatory? \| Allowed values \| Allowed special characters ---------- \| ---------- \| -------------- \| -------------------------- Seconds \| Yes \| 0-59 \| * / , - Minutes \| Yes \| 0-59 \| * / , - Hours \| Yes \| 0-23 \| * / , - Day of month \| Yes \| 1-31 \| * / , - ? Month \| Yes \| 1-12 or JAN-DEC \| * / , - Day of week \| Yes \| 0-6 or SUN-SAT \| * / , - ?` targetSize：到调度时间时，您想扩缩容到的Pod的数目。 runOnce：如果runOnce设置为true，那么任务将只执行一次，第一次执行完则exit。

安装kubernetes-cronhpa-controller

登录容器服务管理控制台。
单击左侧导航栏中的市场 > 应用目录。
在阿里云应用页面右上方名称搜索框中输入kubernetes-cronhpa-controller，然后单击ack-kubernetes-cronhpa-controller组件。
在应用目录-ack-kubernetes-cronhpa-controller页面右侧的创建区域，填写相关创建信息。
- 集群：选择目标集群。资源对象将部署在该集群内。
- 命名空间：选择资源对象所属的命名空间，默认是 default。除了节点、持久化存储卷等底层计算资源以外，大多数资源对象需要作用于命名空间。
- 发布名称：显示资源对象的发布名称。
单击创建，安装kubernetes-cronhpa-controller。

示例1 Cronhpa独立工作

成功安装kubernetes-cronhpa-controller组件后，以下举例如何部署具体的cronhpa。

执行下面的命令，部署示例对象与cronhpa。

kubectl apply -f deployment_cronhpa.yaml

deployment_cronhpa.yaml如下：

---
apiVersion: apps/v1 
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.alibabacloud.com/v1beta1
kind: CronHorizontalPodAutoscaler
metadata:
  labels:
    controller-tools.k8s.io: "1.0"
  name: cronhpa-sample
spec:
   scaleTargetRef:
      apiVersion: apps/v1
      kind: Deployment
      name: nginx-deployment-basic
   jobs:
   - name: "scale-down"
     schedule: "30 */1 * * * *"
     targetSize: 1
   - name: "scale-up"
     schedule: "0 */1 * * * *"
     targetSize: 3

执行以下命令，检查示例应用副本数目。

kubectl get deploy nginx-deployment-basic

➜  kubernetes-cronhpa-controller git:(master) ✗ kubectl get deploy nginx-deployment-basic
NAME                     DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
nginx-deployment-basic   2         2         2            2           9s

执行kubectl describe cronhpa cronhpa-sample命令，查看cronhpa的状态，确认cronhpa的job已提交。

Name:         cronhpa-sample
Namespace:    default
Labels:       controller-tools.k8s.io=1.0
Annotations:  kubectl.kubernetes.io/last-applied-configuration:
                {"apiVersion":"autoscaling.alibabacloud.com/v1beta1","kind":"CronHorizontalPodAutoscaler","metadata":{"annotations":{},"labels":{"controll...
API Version:  autoscaling.alibabacloud.com/v1beta1
Kind:         CronHorizontalPodAutoscaler
Metadata:
  Creation Timestamp:  2019-04-14T10:42:38Z
  Generation:          1
  Resource Version:    4017247
  Self Link:           /apis/autoscaling.alibabacloud.com/v1beta1/namespaces/default/cronhorizontalpodautoscalers/cronhpa-sample
  UID:                 05e41c95-5ea2-11e9-8ce6-00163e12e274
Spec:
  Jobs:
    Name:         scale-down
    Schedule:     30 */1 * * * *
    Target Size:  1
    Name:         scale-up
    Schedule:     0 */1 * * * *
    Target Size:  3
  Scale Target Ref:
    API Version:  apps/v1
    Kind:         Deployment
    Name:         nginx-deployment-basic
Status:
  Conditions:
    Job Id:           38e79271-9a42-4131-9acd-1f5bfab38802
    Last Probe Time:  2019-04-14T10:43:02Z
    Message:
    Name:             scale-down
    Schedule:         30 */1 * * * *
    State:            Submitted
    Job Id:           a7db95b6-396a-4753-91d5-23c2e73819ac
    Last Probe Time:  2019-04-14T10:43:02Z
    Message:
    Name:             scale-up
    Schedule:         0 */1 * * * *
    State:            Submitted
Events:               <none>

说明以上示例中出现的代码，请参见examples目录。

执行下面的命令，部署示例对象、HPA及cronhpa。

kubectl apply -f deployment_cronhpa_hpa.yaml

deployment_cronhpa_hpa.yaml如下：

---
apiVersion: apps/v1
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>
        resources:
          requests:
            cpu: 50m
            memory: 60m
        ports:
        - containerPort: 80
---
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
  name: nginx-deployment-basic-hpa
  namespace: default
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: nginx-deployment-basic
  minReplicas: 1
  maxReplicas: 10
  targetCPUUtilizationPercentage: 50
---
apiVersion: autoscaling.alibabacloud.com/v1beta1
kind: CronHorizontalPodAutoscaler
metadata:
  labels:
    controller-tools.k8s.io: "1.0"
  name: cronhpa-sample
spec:
   scaleTargetRef:
      apiVersion: autoscaling/v1
      kind: HorizontalPodAutoscaler
      name:  nginx-deployment-basic-hpa
   jobs:
   - name: "scale-down"
     schedule: "30 */1 * * * *"
     targetSize: 1
     runOnce: true
   - name: "scale-up"
     schedule: "0 */1 * * * *"
     targetSize: 3
     runOnce: true

执行以下命令，检查示例应用副本数目及HPA。

kubectl get deploy nginx-deployment-basic

NAME                     DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
nginx-deployment-basic   2         2         2            2           9s
-------
kubectl get hpa  nginx-deployment-basic-hpa
NAME                         REFERENCE                           TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
nginx-deployment-basic-hpa   Deployment/nginx-deployment-basic   0%/50%    1         10        2          150m

执行kubectl describe cronhpa cronhpa-sample命令，查看cronhpa的状态。

Name:         cronhpa-sample
Namespace:    default
Labels:       controller-tools.k8s.io=1.0
Annotations:  kubectl.kubernetes.io/last-applied-configuration:
                {"apiVersion":"autoscaling.alibabacloud.com/v1beta1","kind":"CronHorizontalPodAutoscaler","metadata":{"annotations":{},"labels":{"contro
ll...
API Version:  autoscaling.alibabacloud.com/v1beta1
Kind:         CronHorizontalPodAutoscaler
Metadata:
  Creation Timestamp:  2020-04-15T06:02:26Z
  Generation:          32
  Resource Version:    45484074
  Self Link:           /apis/autoscaling.alibabacloud.com/v1beta1/namespaces/default/cronhorizontalpodautoscalers/cronhpa-sample
  UID:                 ae9c547e-7ede-11ea-8a4c-00163e080212
Spec:
  Exclude Dates:  <nil>
  Jobs:
    Name:         scale-down
    Run Once:     false
    Schedule:     30 */1 * * * *
    Target Size:  1
    Name:         scale-up
    Run Once:     false
    Schedule:     0 */1 * * * *
    Target Size:  3
  Scale Target Ref:
    API Version:  autoscaling/v1
    Kind:         HorizontalPodAutoscaler
    Name:         nginx-deployment-basic-hpa
Status:
  Conditions:
    Job Id:           6d5dca76-d120-4d2a-b154-2c39a6650241
    Last Probe Time:  2020-04-15T09:36:30Z
    Message:          cron hpa job scale-down executed successfully. Skip scale replicas because HPA nginx-deployment-basic-hpa current replicas:3 >= de
sired replicas:1.
    Name:             scale-down
    Run Once:         false
    Schedule:         30 */1 * * * *
    State:            Succeed
    Target Size:      1
    Job Id:           26a6176f-c476-4efa-bcf9-3388c6fd6059
    Last Probe Time:  2020-04-15T09:36:00Z
    Message:          cron hpa job scale-up executed successfully. current replicas:2, desired replicas:3.
    Name:             scale-up
    Run Once:         false
    Schedule:         0 */1 * * * *
    State:            Succeed
    Target Size:      3
  Exclude Dates:      <nil>
  Scale Target Ref:
    API Version:  autoscaling/v1
    Kind:         HorizontalPodAutoscaler
    Name:         nginx-deployment-basic-hpa
Events:
  Type    Reason   Age                  From                            Message
  ----    ------   ----                 ----                            -------
  Normal  Succeed  31s (x4 over 3h33m)  cron-horizontal-pod-autoscaler  cron hpa job scale-up executed successfully. current replicas:2, desired replica
s:3.
  Normal  Succeed  1s (x8 over 121m)    cron-horizontal-pod-autoscaler  cron hpa job scale-down executed successfully. Skip scale replicas because HPA n
ginx-deployment-basic-hpa current replicas:3 >= desired replicas:1.

如果cronhpa任务的State是Succeed，则说明最近一次的执行是成功的；如果是Submitted则意味着cronhpa任务已经提交给cron engine，但是截至当前还未执行。等待30秒后可再次查询状态，如果所有任务的State都为Succeed，则全部运行成功。

容器定时伸缩

前提条件

背景信息

安装kubernetes-cronhpa-controller

示例1 Cronhpa独立工作