CKA 不假题 练习笔记 （四）

Q 13： Sidecar Container/Logging

本题目，Logging是目的；Sidecar是手段
Context -
An existing Pod needs to be integrated into the Kubernetes built-in logging architecture (e.g. kubectl logs). Adding a streaming sidecar container is a good and common way to accomplish this requirement.

Task -
Add a sidecar container named sidecar, using the busybox image, to the existing Pod big-corp-app. The new sidecar container has to run the following command:
ls
Use a Volume, mounted at /var/log, to make the log file big-corp-app.log available to the sidecar container.

Q13： 解答（来自chatgpt）

Updated Pod YAML Manifest
This assumes you have access to edit the existing Pod big-corp-app. Save the updated configuration to a file (e.g., big-corp-app.yaml) and apply it:

apiVersion: v1
kind: Pod
metadata:
  name: big-corp-app
spec:
  containers:
  - name: main-container
    image: your-app-image
    volumeMounts:
    - name: log-volume
      mountPath: /var/log
    command: ["/bin/sh", "-c"]
    args: ["echo 'Hello from main container!' >> /var/log/big-corp-app.log; sleep 3600"]
  - name: sidecar  #需要新增部分sidecar 边车容器
    image: busybox #采用最小的image
    volumeMounts:
    - name: log-volume
      mountPath: /var/log
    command: ["/bin/sh", "-c"]
    args: ["tail -f /var/log/big-corp-app.log"]
  volumes: # main-container和sidecar 共用一个volume
  - name: log-volume
    emptyDir: {} 

【追加备注】

1. 此题目其实属于Logging相关，而不是Pod。
2. 通过Sidecar模式，运行一个1MB大小的busybox 来收集同一个pod里的应用Container的日志是一个较为流行的最佳实践。

Q14: Kubectl TOP

Task -
From the pod label name=overloaded-cpu, find pods running high CPU workloads and write the name of the pod consuming most CPU to the file /opt/
KUTR00401/KUTR00401.txt (which already exists).

Q14：解答

root@master:/opt/k8sconfig$sudo kubectl top pods -l name=voerloaded-cpu --sort-by=cpu

Q15: kubelet

Task -
A Kubernetes worker node, named wk8s-node-0 is in state NotReady.
Investigate why this is the case, and perform any appropriate steps to bring the node to a Ready state, ensuring that any changes are made permanent.
(这个题目其实是因为node上的kubelet停止了导致了node不ready。有人提到，kubelet可能配置文件或者service变动，导致无法通过service restart kubelet来重启，但是我考试没有遇到，只是简单启动一下就可以了。）

Q16: PVC

Task -
Create a new PersistentVolumeClaim:
✑ Name: pv-volume
✑ Class: csi-hostpath-sc
✑ Capacity: 10Mi
Create a new Pod which mounts the PersistentVolumeClaim as a volume:
✑ Name: web-server
✑ Image: nginx
✑ Mount path: /usr/share/nginx/html
Configure the new Pod to have ReadWriteOnce access on the volume.
Finally, using kubectl edit or kubectl patch expand the PersistentVolumeClaim to a capacity of 70Mi and record that change.

Q16: 解答

pvc-pv-volume.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pv-volume
spec:
  storageClassName: csi-hostpath-sc
  capacity:
    storage: 10Mi

https://kubernetes.io/docs/concepts/storage/persistent-volumes/

pod-web-server.yaml

apiVersion: v1
kind: Pod
metadata:
  name: pv-volume-pod
spec:
  containers:
  - name: web-server
    image: nginx
    volumeMounts:
    - name: pv-test
      mountPath: /usr/share/nginx/html
  volumes:
  - name: pv-test
    persistentVolumeClass: csi-hostpath-sc
      Cliamname: pv-volume

kubectl edit pvc pv-volume 此命令去edit storage

Q17: NGINX-Ingress

Task -
Create a new nginx Ingress resource as follows:
✑ Name: pong
✑ Namespace: ing-internal
✑ Exposing service hello on path /hello using service port 5678

Q17: 解答

考试时候，先定位到kubernets官网上关于ingress部分，然后copy里面的yaml example 改写即可

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: pong
  namespace: ing-internal
spec:
  ingressClassName: nginx # 定义ingress的类型为nginx，通常nginx是default，可以不显性设定
  rules:
  - http:
      paths:
      - path: /hello
        pathType: Prefix
        backend:
          service:
            name: hello # backend的service是“hello”
            port:
              number: 5678

【追加备注】

1. 此题目可能需要先通过kubectl get ingressclass 来确认下是否已经存在ingress class，如果没有可能需要新建ingressclass。
2. CNCF将不早于2025年2月10日开始换题，根据新的考试内容，ingress相关题目大概率会被Gateway API取代！

Q18：Pod

Task -
Schedule a Pod as follows:

• Name: kucc1
• App Containers: 2
• Container Name/images:
o redis
o consul

Q18：解答

考试时候，先定位到kubernets官网上关于pod部分，然后copy里面的yaml example 改写即可。

apiVersion: v1
kind: Pod
metadata:
  name: kucc1
spec:
  containers:
  - name: redis
    image: redis
    imagePullPolicy: IfNotPresent #非必须要定义
 - name: consul
    image: consul
    imagePullPolicy: IfNotPresent #非必须要定义

本人准备CKA考试的笔记全部完成，不承诺答案一定正确，请独立思考。