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As enterprises race to scale their infrastructure to handle increasing workloads, many find it’s time to migrate from Cron Jobs or Windows Task Scheduler. Containerization like Docker or Kubernetes are excellent ways to automate application deployment, scaling, and management, but lack sophisticated job scheduling.

Redwood’s RunMyJobs fills that gap.

The Drawbacks Of OS Schedulers

When it comes to batch jobs and workload management, Cron Jobs and Windows Task Scheduler simply don’t integrate as cleanly with containers.

  1. They aren’t natively built to understand container infrastructure
  2. They can’t scale up or down based on container resource usage
  3. They don’t have visibility into container performance or resource usage, making it difficult to troubleshoot scheduled jobs across containers
  4. They’re not designed to orchestrate multi-container jobs
  5. Schedulers may have more permissions than are needed for job execution, making them a potential security risk

Kubernetes CronJob

Kubernetes CronJobs are a custom implementation of the traditional UNIX utility called “cron.” A cron job is a task that’s executed on a repeating, regular schedule. Cron schedules and executes tasks in UNIX and Linux systems via a command line utility called crontab. Due to Cron’s reliance on custom scripts for complex tasks, cron jobs are most suited to basic tasks like scheduling backups, report generation, or sending emails.

A cron job has a few important limitations. Modifying a cron job applies changes to all the new jobs that run after the modification. Any job that runs before the modification is complete will run without the modification. It’s not easy to stage a cron job to execute without a manual deployment.

There are also certain circumstances where a job may not run, or it may run twice, without the correct syntax or an unset, default, or incorrect value. The lack of reliability among default presets and complicated syntax require intense manual work, slowing down productivity. Any logging of cron job executions has to be done manually and intentionally.

Teams can run automated tasks on Kubernetes using a Kubernetes CronJob object with a config file, but they are still subject to the limitations of CronJobs itself.

Kubernetes and Windows Task Scheduler

Microsoft is one of the most common operating systems and application platforms across many organizations. Teams that run Docker or other containerized environments can configure job scheduling in Windows with Kubernetes. Windows can use Kubectl commands and behave similarly to Linux containers.

However, Windows Task Scheduler offers only basic scheduling capabilities and is designed primarily to run tasks on a local machine, not across platforms or IT environments. It is therefore not desirable for large teams and organizations.

Both CronJobs and Windows Task Scheduler have similar drawbacks. Both are siloed and point-based and are not designed to handle large-scale tasks across multiple servers.

Automating Kubernetes with a Job Scheduling Automation Tool

An advanced enterprise scheduling tool like Redwood’s RunMyJobs enables teams to simplify their container-based automation. RunMyJobs can automate what teams spin up in a Kubernetes cluster, node, or kubelet.

RunMyJobs is an advanced automation and orchestration engine fully capable of working with Kubernetes. It has an object-oriented design that integrates with and natively understands Kubernetes CronJob objects, namespaces, pod names, and metrics (e.g. cpu, i/o, ram utilization). It even understands native Kubernetes constructs like onfailure, restartpolicy, pod lifecycles, kubectl logs, spec.schedule, selectors, and tools like busybox/minikube. It works across multiple cloud platforms (e.g. Amazon, Azure, Google, and others) and delivers workload automation that orchestrates multiple microservices into a single end-to-end service for your enterprise and enterprise scheduler tools.

Frequently Asked Questions

How can I automate Kubernetes job scheduling in RunMyJobs by Redwood?

RunMyJobs supports the Kubernetes API, so once you’ve set up your environment, permissions, and security configurations, you can create Kubernetes jobs. With RunMyJobs, it’s easy to set up batch scheduling, job scheduling, and automation for use cases like automated application deployment, resource management, or cluster monitoring. For each task, create a corresponding job. Then use our API or kubectl command line to execute the jobs. You can schedule a job run at scheduled times or desired intervals or triggers. Explore how Redwood’s enterprise job scheduling platform can enhance your business.

How does Kubernetes job scheduling work in Cron?

There are a few idiosyncracies to know with CronJob and Kubernetes. One Cron Job object is like one line of a crontab file, and it runs a scheduled job.

When creating new Jobs and new Pods for a CronJob, the is the basis for naming. The name must be a valid DNS subdomain value, but best practice is to follow rules for a DNS label and use fewer than 52 characters, as the CronJob controller will automatically add 11 characters to your provided name and a job name cannot be more than 63 characters in total. Writing a Cron Job spec requires schedule syntax, which specifies the intervals and times for the Job to run.

The job template has the same schema as a Job but does not have an apiVersion. Templated jobs can have CronJob metadata specifications such as labels or annotations. The next field, delayed job start deadline, is optional and defines a deadline for starting a Job if the Job misses its scheduled time.

The concurrency policy field is also optional and specifies the Allow, which allows concurrently running jobs; Forbid, which does not allow concurrent runs; or Replace, which replaces a running job with a new job run if the previous job hasn’t finished running. You can also set a time zone, job history limit, and schedule suspension. Discover how efficient Redwood’s platform is at enterprise job scheduling.

Why can't I use the Kubernetes job scheduler?

Kubernetes’ default scheduler, kube-scheduler, is a control plan process that determines which nodes are valid placements for each Pod in the work queue. Kube-scheduler cannot manage jobs holistically or dispatch jobs to multiple clusters. An enterprise job scheduling software like RunMyJobs by Redwood enables organizations to schedule jobs and workflows across their business processes and environment from a single control plane. This gives IT, DevOps, and security teams a single point of visibility to holistically manage jobs. Discover how Redwood automates business processes on a cloud-native platform.