避免在 Kubernetes 中为一个 cron 执行点运行多个 cron 作业

Question

编辑：问题解决了，这是我的错误，我只是使用了错误的cron设置。我假设“*2***”在2点时每天只运行一次，但实际上它在2点后每分钟运行一次。所以Kubernetes的行为是正确的。

我一直在一个 cron 执行点运行多个作业。但似乎只有当这些作业的运行时间非常短时。知道为什么会发生这种情况以及如何防止它吗？我使用并发策略：禁止，回退限制：0和重新启动策略：从不。

一个cron作业的示例，该作业应该每天运行一次，但在其预定运行时间之后运行多次：

job-1554346620                   1/1           11s        4h42m   
job-1554346680                   1/1           11s        4h41m                     
job-1554346740                   1/1           10s        4h40m 

相关配置：

apiVersion: batch/v1beta1
kind: CronJob
metadata:
  name: job
spec:
  schedule: "* 2 * * *"
  concurrencyPolicy: Forbid
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: job
              image: job_image:latest
              command: ["rake", "run_job"]
          restartPolicy: Never
          imagePullSecrets:
            - name: regcred
      backoffLimit: 0

Answer 1

嗨，不清楚您期望的是什么-仔细研究这个问题，但是如果我理解正确的话，您的意思是不要同时运行所有的cron jobs:< br > 1。第一种选择是改变他们的计划时间。第二个选项尝试在您的规格模板中使用其他选项，如-并行作业-描述:https://kubernetes . io/docs/concepts/workloads/controllers/Jobs-run-to-completion/

msgstr"对于工作队列作业，您必须离开。spec.completions未设置，并将spec.parallelism设置为非负整数"

  jobTemplate:
    spec:
      parallelism: 1
      template:

要重新创建此任务，请提供更多详细信息。< br >

此外，对于“工作历史”，默认成功的工作历史限制和失败的工作历史限制分别设置为3和1。
请在：https://kubernetes.io/docs/tasks/job/如果您有兴趣，您可以在“规格”部分设置限制：

successfulJobsHistoryLimit: 1

failedJobsHistoryLimit: 1

希望对此有所帮助。

Answer 2

在k8s上运行CronJobs最常见的问题是：

生成许多pod，这些pod消耗所有集群资源

设置适当的 CronJob 限制非常重要

如果您不确定自己需要什么，只需将此示例作为模板：

apiVersion: batch/v1beta1
kind: CronJob
metadata:
  name: my-first-conjob
  namespace: devenv-admitriev
spec:
  schedule: "*/10 * * * *" # MM HH DD MM WKD -- Minutes, Hour, Day, Month, Weekday (eg. Sun, Mon)
  successfulJobsHistoryLimit: 3 # how many completed jobs should be kept
  failedJobsHistoryLimit: 1 # how many failed jobs should be kept
  suspend: false # Here you can suspend cronjob without deliting it
  concurrencyPolicy: Forbid # Choose Forbid if you don't want concurrent executions of your Job

  # The amount of time that Kubernetes can miss and still start a job.
  # If Kubernetes missed too many job starts (100)
  # then Kubernetes logs an error and doesn’t start any future jobs.
  startingDeadlineSeconds: 300 # if a job hasn't started in this many seconds, skip
  jobTemplate:
    spec:
      parallelism: 1 # How many pods will be instantiated at once.
      completions: 1 # How many containers of the job are instantiated one after the other (sequentially) inside the pod.
      backoffLimit: 3 # Maximum pod restarts in case of failure
      activeDeadlineSeconds: 1800 # Limit the time for which a Job can continue to run
      template:
        spec:
          restartPolicy: Never # If you want to restart - use OnFailure
          terminationGracePeriodSeconds: 30
          containers:
          - name: my-first-conjob
            image: busybox
            command:
              - /bin/sh
            args:
              - -c
              - date; echo sleeping....; sleep 90s; echo exiting...;
            resources:
              requests:
                memory: '128Mi'
              limits:
                memory: '1Gi'