Multi kube-sheduler

General Discussions
1

Hello there !
I’m trying to create a kube-scheduler that will be used by my organisation pod deployment (a data-center). The objective would be to have the pods of any deployment be split equally between the two sites of the data-center. To archive this I created a new kube-scheduler manifest (see below), in which i changed the Ports that are used and added a new configuration file (see below) using the --config parameter. The problem is that even after setting the --port parameter to a new port that isn’t already used by the original kube-scheduler, it still tries to use the old one. As such the new kube scheduler can’t start:

I1109 20:27:59.225996       1 registry.go:173] Registering SelectorSpread plugin
I1109 20:27:59.226097       1 registry.go:173] Registering SelectorSpread plugin
I1109 20:27:59.926994       1 serving.go:331] Generated self-signed cert in-memory
failed to create listener: failed to listen on 0.0.0.0:10251: listen tcp 0.0.0.0:10251: bind: address already in use

How can I force the use of the specified port OR how can I delete the original kube-scheduler so that there won’t be any conflict between the two. The first solution would be preferable.

Cluster information:

Configuration kube-scheduler (manifest - /etc/kubernetes/manifest/kube-scheduler.yaml) :

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    component: kube-scheduler
    tier: control-plane
  name: kube-scheduler
  namespace: kube-system
spec:
  containers:
  - command:
    - kube-scheduler
    - --authentication-kubeconfig=/etc/kubernetes/scheduler.conf
    - --authorization-kubeconfig=/etc/kubernetes/scheduler.conf
    - --bind-address=127.0.0.1
    - --kubeconfig=/etc/kubernetes/scheduler.conf
    - --leader-elect=true
      #- --port=0
    image: k8s.gcr.io/kube-scheduler:v1.19.3
    imagePullPolicy: IfNotPresent
    livenessProbe:
      failureThreshold: 8
      httpGet:
        host: 127.0.0.1
        path: /healthz
        port: 10259
        scheme: HTTPS
      initialDelaySeconds: 10
      periodSeconds: 10
      timeoutSeconds: 15
    name: kube-scheduler
    resources:
      requests:
        cpu: 100m
    startupProbe:
      failureThreshold: 24
      httpGet:
        host: 127.0.0.1
        path: /healthz
        port: 10259
        scheme: HTTPS
      initialDelaySeconds: 10
      periodSeconds: 10
      timeoutSeconds: 15
    volumeMounts:
    - mountPath: /etc/kubernetes/scheduler.conf
      name: kubeconfig
      readOnly: true
  hostNetwork: true
  priorityClassName: system-node-critical
  volumes:
  - hostPath:
      path: /etc/kubernetes/scheduler.conf
      type: FileOrCreate
    name: kubeconfig
status: {}

Configuration kube-custom-scheduler.yaml (/etc/kubernetes/manifest/kube-custom-scheduler.yaml):

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    component: kube-custom-scheduler
    tier: control-plane
  name: kube-custom-scheduler
  namespace: kube-system
spec:
  containers:
  - command:
    - kube-scheduler 
    - --config=/etc/kubernetes/scheduler-custom.conf
    - --master=true
    - --authentication-kubeconfig=/etc/kubernetes/scheduler.conf
    - --authorization-kubeconfig=/etc/kubernetes/scheduler.conf
    - --bind-address=127.0.0.1
    - --kubeconfig=/etc/kubernetes/scheduler.conf
    - --leader-elect=false
    - --secure-port=10269
    - --scheduler-name=kube-custom-shceduler
    - --port=10261
    image: k8s.gcr.io/kube-scheduler:v1.19.3
    imagePullPolicy: IfNotPresent
    livenessProbe:
      failureThreshold: 8
      httpGet:
        host: 127.0.0.1
        path: /healthz
        port: 10269
        scheme: HTTPS
      initialDelaySeconds: 10
      periodSeconds: 10
      timeoutSeconds: 15
    name: kube-scheduler
    resources:
      requests:
        cpu: 100m
    startupProbe:
      failureThreshold: 24
      httpGet:
        host: 127.0.0.1
        path: /healthz
        port: 10269
        scheme: HTTPS
      initialDelaySeconds: 10
      periodSeconds: 10
      timeoutSeconds: 15
    volumeMounts:
    - mountPath: /etc/kubernetes/scheduler.conf
      name: kubeconfig
      readOnly: true
    - mountPath: /etc/kubernetes/scheduler-custom.conf
      name: customconfig
      readOnly: true
  hostNetwork: true
  priorityClassName: system-node-critical
  volumes:
  - hostPath:
      path: /etc/kubernetes/scheduler.conf
      type: FileOrCreate
    name: kubeconfig
  - hostPath:
      path: /etc/kubernetes/scheduler-custom.conf
      type: FileOrCreate
    name: customconfig 
status: {}

Custom configuration mentioned in the kube-custom-scheduler.yaml (/etc/kubernetes/scheduler-custom.conf):
```
apiVersion: kubescheduler.config.k8s.io/v1beta1
kind: KubeSchedulerConfiguration

profiles:
  - pluginConfig:
      - name: PodTopologySpread
        args:
          defaultConstraints:
            - maxSkew: 1
              topologyKey: topology.kube.io/datacenter 
              whenUnsatisfiable: ScheduleAnyway 
```

Kubernetes version: v1.19.3
Cloud being used: bare-metal
Installation method: kubeadm (calico, metallb)
Host OS: Debian 10 Buster
CNI and version: Calico v3.16.4 (k8s,bgp,kubeadm,kdd)
CRI and version: Docker v19.03.13
Please if you need any more information, don’t hesitate.
Have a nice day !

1 Like
2

Hi, how did you solve this problem? I met the same ’ 0.0.0.0:10251: bind: address already in use error ’ when i try to create multiple shceduler.