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接上一篇备战CKA每日一题——第1天

昨日考题

以下 Daemonset yaml 中，哪些是正确的？（多选）

A. apiVersion: apps/v1 kind: DaemonSet metadata: name: fluentd-elasticsearch namespace: default labels: k8s-app: fluentd-logging spec: selector: matchLabels: name: fluentd-elasticsearch template: metadata: labels: name: fluentd-elasticsearch spec: containers: - name: fluentd-elasticsearch image: gcr.io/fluentd-elasticsearch/fluentd:v2.5.1 restartPolicy: Never
B. apiVersion: apps/v1 kind: DaemonSet metadata: name: fluentd-elasticsearch namespace: default labels: k8s-app: fluentd-logging spec: selector: matchLabels: name: fluentd-elasticsearch template: metadata: labels: name: fluentd-elasticsearch spec: containers: - name: fluentd-elasticsearch image: gcr.io/fluentd-elasticsearch/fluentd:v2.5.1 restartPolicy: Onfailure
C. apiVersion: apps/v1 kind: DaemonSet metadata: name: fluentd-elasticsearch namespace: default labels: k8s-app: fluentd-logging spec: selector: matchLabels: name: fluentd-elasticsearch template: metadata: labels: name: fluentd-elasticsearch spec: containers: - name: fluentd-elasticsearch image: gcr.io/fluentd-elasticsearch/fluentd:v2.5.1 restartPolicy: Always
D. apiVersion: apps/v1 kind: DaemonSet metadata: name: fluentd-elasticsearch namespace: default labels: k8s-app: fluentd-logging spec: selector: matchLabels: name: fluentd-elasticsearch template: metadata: labels: name: fluentd-elasticsearch spec: containers: - name: fluentd-elasticsearch image: gcr.io/fluentd-elasticsearch/fluentd:v2.5.1

昨日答案

CD

昨日解析

在考试时，只能用谷歌浏览器，并打开两个标签页，一个是考题的标签页，另一个是kubernetes官网标签页。https://kubernetes.io/
查询daemonset的说明文档，见以下链接：
https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/

A Pod Template in a DaemonSet must have a RestartPolicy equal to Always, or be unspecified, which defaults to Always.
Daemonset里的pod Template下必须有RestartPolicy，如果没指定，会默认为Always

restartPolicy 字段，可选值为 Always、OnFailure 和 Never。默认为 Always。 一个Pod中可以有多个容器，restartPolicy适用于Pod 中的所有容器。restartPolicy作用是，让kubelet重启失败的容器。

另外Deployment、Statefulset的restartPolicy也必须为Always，保证pod异常退出，或者健康检查livenessProbe失败后由kubelet重启容器。
https://kubernetes.io/zh/docs/concepts/workloads/controllers/deployment/

Job和CronJob是运行一次的pod，restartPolicy只能为OnFailure或Never，确保容器执行完成后不再重启。
https://kubernetes.io/docs/concepts/workloads/controllers/jobs-run-to-completion/

今日考题

在Kubernetes PVC+PV体系下通过CSI实现的volume plugins动态创建pv到pv可被pod使用有哪些组件需要参与？

A. PersistentVolumeController + CSI-Provisoner + CSI controller plugin
B. AttachDetachController + CSI-Attacher + CSI controller plugin
C. Kubelet + CSI node plugin