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Kube Scheduler

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In this section, we will take a look at kube-scheduler.

kube-scheduler is responsible for scheduling pods on nodes.

• The kube-scheduler is only responsible for deciding which pod goes on which node. It doesn’t actually place the pod on the nodes, that’s the job of the kubelet.

  

Why do you need a Scheduler?

Install kube-scheduler - Manual

• Download the kubescheduler binary from the kubernetes release pages kube-scheduler. For example: To download kube-scheduler v1.13.0, Run the below command.

  $ wget https://storage.googleapis.com/kubernetes-release/release/v1.13.0/bin/linux/amd64/kube-scheduler
  

• Extract it

• Run it as a service

  

View kube-scheduler options - kubeadm

• If you set it up with kubeadm tool, kubeadm tool will deploy the kube-scheduler as pod in kube-system namespace on master node.

  $ kubectl get pods -n kube-system
  

• You can see the options for kube-scheduler in pod definition file that is located at /etc/kubernetes/manifests/kube-scheduler.yaml

  $ cat /etc/kubernetes/manifests/kube-scheduler.yaml
  

  

• You can also see the running process and effective options by listing the process on master node and searching for kube-apiserver.

  $ ps -aux | grep kube-scheduler
  

  

  K8s Reference Docs:

  • https://kubernetes.io/docs/reference/command-line-tools-reference/kube-scheduler/
  • https://kubernetes.io/docs/concepts/scheduling-eviction/kube-scheduler/
  • https://kubernetes.io/docs/concepts/overview/components/
  • https://kubernetes.io/docs/tasks/extend-kubernetes/configure-multiple-schedulers/