Crontab hpa scheduler. There is already a work here. I found this repo's way of configuration is elegant but there is some issues about crontabbing inside a docker. It is implemented in python so i decide to reimplement it with client-go.
Install helm charts in the namespaces that contains deployments need to be scheduled.
helm install cronhpacontroller chart/cronhpa [-n namespace]And add an annotation named qsun.tencent.com/cronhpa in form of json.
You can set replicas (for those deployments who don't have an hpa) or minReplicas and maxReplicas
(for hpas whose targets are the deployments with the annotation.)
metadata:
annotations:
qsun.tencent.com/cronhpa: |
[
{"schedule": "1 * * * *", "replicas": 4},
{"schedule": "1 * * * *", "minReplicas": 1, "maxReplicas": 20}
]You can refer to the logs to check if the controller works as expected. Grep deployment's name from the log.
$> kubectl logs -f cronhpacontroller-7c5446789f-97wvk cronhpa | grep "act10"
time="2020-04-03T02:24:55Z" level=info msg="Job will be added: act10@\"[\n {\"schedule\": \"1 * * * *\", \"replicas\": 4, \"minReplicas\": 5}, \n {\"schedule\": \"1 * * * *\", \"replicas\": 4, \"maxReplicas\": 6}\n]\n\""
time="2020-04-03T02:24:55Z" level=debug msg="Job added: act10 | 4 | 5 | 0"
time="2020-04-03T02:24:55Z" level=debug msg="Job added: act10 | 4 | 0 | 6"
time="2020-04-03T02:24:55Z" level=info msg="Cron jobs for \"act10\" is started."
time="2020-04-03T02:25:01Z" level=info msg="\"act10\" replicas is set to 4"
time="2020-04-03T02:25:01Z" level=info msg="\"act10\" replicas is set to 4"Adding/Modifying/Deleting the annotation or adding/deleting the hpa, the controller will make corresponding changes to crontabs.
# Requires go v1.13+
GOOS=linux go build -o ./bin/cronhpa -mod vendor ./cmd/cron-hpa-controller/main.go
# You can directly use csighub.tencentyun.com/qwertysun/cronhpa:v14 for that
Docker build -f build/Dockerfile -t cronhpa .kube-system and enable the function by labeling a namespace.