Custom Kube-Scheduler: Why And How to Set it Up in Kubernetes

The default Kubernetes scheduler, kube-scheduler, may not always align with specific use cases. A custom kube-scheduler allows users to define their own logic for workload placement. This can be useful in industries like finance or healthcare where fine-grained control is needed beyond the capabilities of the default scheduler. To create a custom kube-scheduler, one must first create a configuration file defining how the scheduler behaves. Then, deploy the custom Kubernetes scheduler as a Pod within the cluster and give it permissions to do its work. Finally, schedule Pods with the custom kube-scheduler by setting the schedulerName in the deployment YAML. Troubleshooting steps for a custom kube-scheduler include checking scheduler logs, verifying the Pod's schedulerName, ensuring resource constraints are met, and checking node affinity/anti-affinity rules and taints/tolerations.