CKA 模拟真题 Killer.sh | Question 9 | Kill Scheduler, Manual Scheduling

Use context: kubectl config use-context k8s-c2-AC

Ssh into the controlplane node with ssh cluster2-controlplane1 . Temporarily stop the kube-scheduler, this means in a way that you can start it again afterwards.

Create a single Pod named manual-schedule of image httpd:2.4-alpine , confirm it’s created but not scheduled on any node.

Now you’re the scheduler and have all its power, manually schedule that Pod on node cluster2-controlplane1. Make sure it’s running.

Start the kube-scheduler again and confirm it’s running correctly by creating a second Pod named manual-schedule2 of image httpd:2.4-alpine and check if it’s running on cluster2-node1.

译文

用 ssh cluster2-controlplane1 登录控制板节点。暂时停止 kube-scheduler ，这意味着你可以在之后再次启动它。

创建一个名为 manual-schedule 的 Pod，镜像为 httpd:2.4-alpine ，确认它已经创建，但没有在任何节点上调度。

现在你是调度员，拥有它的所有权力，在 cluster2-controlplane1 节点上手动调度这个 Pod 。确保它正在运行。

再次启动 kube-scheduler ，通过创建第二个Pod manual-schedule2 使用镜像 httpd:2.4-alpine ，并检查它是否在 cluster2-node1 上运行，确认它运行正常。

解答

kubectl config use-context k8s-c2-AC

检查并找出 controlplane 节点,

k get node

node-schedule-3-0

连接上远程节点并检查调度程序是否正在运行。

ssh cluster2-controlplane1
root@cluster2-controlplane1:~# kubectl -n kube-system get pod | grep schedule

node-schedule-3-1

通过移出yaml文件结束调度pod

root@cluster2-controlplane1:~# mv /etc/kubernetes/manifests/kube-scheduler.yaml .
root@cluster2-controlplane1:~# pwd
root@cluster2-controlplane1:~# kubectl -n kube-system get pod | grep schedule

node-schedule-3-2

创建pod,并检查状态

k run manual-schedule --image=httpd:2.4-alpine
k get pod manual-schedule -o wide

node-schedule-3-3

编辑pod

k get pod manual-schedule -o yaml > 9.yaml

9.yaml

# 9.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: "2020-09-04T15:51:02Z"
  labels:
    run: manual-schedule
  managedFields:
...
    manager: kubectl-run
    operation: Update
    time: "2020-09-04T15:51:02Z"
  name: manual-schedule
  namespace: default
  resourceVersion: "3515"
  selfLink: /api/v1/namespaces/default/pods/manual-schedule
  uid: 8e9d2532-4779-4e63-b5af-feb82c74a935
spec:
  nodeName: cluster2-controlplane1        # add the controlplane node name
  containers:
  - image: httpd:2.4-alpine
    imagePullPolicy: IfNotPresent
    name: manual-schedule
    resources: {}
    terminationMessagePath: /dev/termination-log
    terminationMessagePolicy: File
    volumeMounts:
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: default-token-nxnc7
      readOnly: true
  dnsPolicy: ClusterFirst
...

由于我们不能用kubectl应用或kubectl编辑，在这种情况下，我们需要删除并创建或替换

k -f 9.yaml replace --force
k get pod manual-schedule -o wide

node-schedule-3-4

再次调度

ssh cluster2-controlplane1
root@cluster2-controlplane1:~# mv kube-scheduler.yaml /etc/kubernetes/manifests/
root@cluster2-controlplane1:~# kubectl -n kube-system get pod | grep schedule
root@cluster2-controlplane1:~# exit

node-schedule-3-5

k run manual-schedule2 --image=httpd:2.4-alpine

node-schedule-3-6