# kubernetes-cronhpa-controller **Repository Path**: beiwei/kubernetes-cronhpa-controller ## Basic Information - **Project Name**: kubernetes-cronhpa-controller - **Description**: kubernetes-cronhpa-controller is a HPA controller that allows to scale your workload based on time schedule. - **Primary Language**: Go - **License**: Not specified - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 1 - **Created**: 2021-12-11 - **Last Updated**: 2024-11-27 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README # kubernetes-cronhpa-controller [![License](https://img.shields.io/badge/license-Apache%202-4EB1BA.svg)](https://www.apache.org/licenses/LICENSE-2.0.html) [![Build Status](https://travis-ci.org/AliyunContainerService/kubernetes-cronhpa-controller.svg?branch=master)](https://travis-ci.org/AliyunContainerService/kubernetes-cronhpa-controller) ## Overview `kubernetes-cronhpa-controller` is a kubernetes cron horizontal pod autoscaler controller using `crontab` like scheme. You can use `CronHorizontalPodAutoscaler` with any kind object defined in kubernetes which support `scale` subresource(such as `Deployment` and `StatefulSet`). ## Installation 1. install CRD ```$xslt kubectl apply -f config/crds/autoscaling_v1beta1_cronhorizontalpodautoscaler.yaml ``` 2. install RBAC settings ```$xslt # create ClusterRole kubectl apply -f config/rbac/rbac_role.yaml # create ClusterRolebinding and ServiceAccount kubectl apply -f config/rbac/rbac_role_binding.yaml ``` 3. deploy kubernetes-cronhpa-controller ```$xslt kubectl apply -f config/deploy/deploy.yaml ``` 4. verify installation ```$xslt kubectl get deploy kubernetes-cronhpa-controller -n kube-system -o wide ➜ kubernetes-cronhpa-controller git:(master) ✗ kubectl get deploy kubernetes-cronhpa-controller -n kube-system NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE kubernetes-cronhpa-controller 1 1 1 1 49s ``` ## Example Please try out the examples in the examples folder. 1. Deploy sample workload and cronhpa ```$xslt kubectl apply -f examples/deployment_cronhpa.yaml ``` 2. Check deployment replicas ```$xslt 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 ``` 3. Describe cronhpa status ```$xslt kubectl describe cronhpa cronhpa-sample 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: Exclude Dates: 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: apps/v1beta2 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 Run Once: false Schedule: 30 */1 * * * * State: Submitted Job Id: a7db95b6-396a-4753-91d5-23c2e73819ac Last Probe Time: 2019-04-14T10:43:02Z Message: Name: scale-up Run Once: false Schedule: 0 */1 * * * * State: Submitted Exclude Dates: Scale Target Ref: API Version: apps/v1beta2 Kind: Deployment Name: nginx-deployment-basic Events: ``` if the `State` of cronhpa job is `Succeed` that means the last execution is successful. `Submitted` means the cronhpa job is submitted to the cron engine but haven't be executed so far. Wait for 30s seconds and check the status. ``` ➜ kubernetes-cronhpa-controller git:(master) kubectl describe cronhpa cronhpa-sample Name: cronhpa-sample Namespace: default Labels: controller-tools.k8s.io=1.0 Annotations: API Version: autoscaling.alibabacloud.com/v1beta1 Kind: CronHorizontalPodAutoscaler Metadata: Creation Timestamp: 2019-11-01T12:49:57Z Generation: 1 Resource Version: 47812775 Self Link: /apis/autoscaling.alibabacloud.com/v1beta1/namespaces/default/cronhorizontalpodautoscalers/cronhpa-sample UID: 1bbbab8a-fca6-11e9-bb47-00163e12ab74 Spec: Exclude Dates: Jobs: Name: scale-down Run Once: false Schedule: 30 */1 * * * * Target Size: 2 Name: scale-up Run Once: false Schedule: 0 */1 * * * * Target Size: 3 Scale Target Ref: API Version: apps/v1beta2 Kind: Deployment Name: nginx-deployment-basic2 Status: Conditions: Job Id: 157260b9-489c-4a12-ad5c-f544386f0243 Last Probe Time: 2019-11-05T03:47:30Z Message: cron hpa job scale-down executed successfully. current replicas:3, desired replicas:2 Name: scale-down Run Once: false Schedule: 30 */1 * * * * State: Succeed Job Id: 5bab7b8c-158a-469c-a68c-a4657486e2a5 Last Probe Time: 2019-11-05T03:48:00Z 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 Exclude Dates: Scale Target Ref: API Version: apps/v1beta2 Kind: Deployment Name: nginx-deployment-basic Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Succeed 42m (x5165 over 3d14h) cron-horizontal-pod-autoscaler cron hpa job scale-down executed successfully. current replicas:3, desired replicas:1 Normal Succeed 30m cron-horizontal-pod-autoscaler cron hpa job scale-up executed successfully. current replicas:1, desired replicas:3 Normal Succeed 17m (x13 over 29m) cron-horizontal-pod-autoscaler cron hpa job scale-up executed successfully. current replicas:2, desired replicas:3 Normal Succeed 4m59s (x26 over 29m) cron-horizontal-pod-autoscaler cron hpa job scale-down executed successfully. current replicas:3, desired replicas:2 ``` 🍻Cheers! It works. ## Implementation Details The following is an example of a `CronHorizontalPodAutoscaler`. ```$xslt apiVersion: autoscaling.alibabacloud.com/v1beta1 kind: CronHorizontalPodAutoscaler metadata: labels: controller-tools.k8s.io: "1.0" name: cronhpa-sample namespace: default spec: scaleTargetRef: apiVersion: apps/v1beta2 kind: Deployment name: nginx-deployment-basic jobs: - name: "scale-down" schedule: "30 */1 * * * *" targetSize: 1 - name: "scale-up" schedule: "0 */1 * * * *" targetSize: 3 ``` The `scaleTargetRef` is the field to specify workload to scale. If the workload supports `scale` subresource(such as `Deployment` and `StatefulSet`), `CronHorizontalPodAutoscaler` should work well. `CronHorizontalPodAutoscaler` support multi cronhpa job in one spec. The cronhpa job spec need three fields: * name `name` should be unique in one cronhpa spec. You can distinguish different job execution status by job name. * schedule The scheme of `schedule` is similar with `crontab`. `kubernetes-cronhpa-controller` use an enhanced cron golang lib （go-cron） which support more expressive rules. The cron expression format is as described below: ```$xslt Field name | Mandatory? | Allowed values | Allowed special characters ---------- | ---------- | -------------- | -------------------------- Seconds | Yes | 0-59 | * / , - Minutes | Yes | 0-59 | * / , - Hours | Yes | 0-23 | * / , - Day of month | Yes | 1-31 | * / , - ? Month | Yes | 1-12 or JAN-DEC | * / , - Day of week | Yes | 0-6 or SUN-SAT | * / , - ? ``` #### Asterisk ( * ) The asterisk indicates that the cron expression will match for all values of the field; e.g., using an asterisk in the 5th field (month) would indicate every month. #### Slash ( / ) Slashes are used to describe increments of ranges. For example 3-59/15 in the 1st field (minutes) would indicate the 3rd minute of the hour and every 15 minutes thereafter. The form "*\/..." is equivalent to the form "first-last/...", that is, an increment over the largest possible range of the field. The form "N/..." is accepted as meaning "N-MAX/...", that is, starting at N, use the increment until the end of that specific range. It does not wrap around. #### Comma ( , ) Commas are used to separate items of a list. For example, using "MON,WED,FRI" in the 5th field (day of week) would mean Mondays, Wednesdays and Fridays. #### Hyphen ( - ) Hyphens are used to define ranges. For example, 9-17 would indicate every hour between 9am and 5pm inclusive. #### Question mark ( ? ) Question mark may be used instead of '*' for leaving either day-of-month or day-of-week blank. more schedule scheme please check this doc. * targetSize `TargetSize` is the size you desired to scale when the scheduled time arrive. * runOnce if `runOnce` is true then the job will only run and exit after the first execution. * excludeDates excludeDates is a dates array. The job will skip the execution when the dates is matched. The minimum unit is day. If you want to skip the date(November 15th), You can specific the excludeDates like below. ```$xslt excludeDates: - "* * * 15 11 *" ``` ## Common Question * Cloud `kubernetes-cronhpa-controller` and HPA work together? Yes and no is the answer. `kubernetes-cronhpa-controller` can work together with hpa. But if the desired replicas is independent. So when the HPA min replicas reached `kubernetes-cronhpa-controller` will ignore the replicas and scale down and later the HPA controller will scale it up. ## Contributing Please check CONTRIBUTING.md ## License This software is released under the Apache 2.0 license.