CKA 过关宝典

firemoon
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01 Task - 英文

Create a new ClusterRole named deployment-clusterrole that only allows the creation of the following resource types:

  • Deployment
  • StatefulSet
  • DaemonSet Create a new ServiceAccount named cicd-token in the existing namespace app-team1. Limited to namespace app-team1, bind the new ClusterRole deployment-clusterrole to the new ServiceAccount cicd-token.
kubectl create ns app-team1
kubectl create serviceaccount cicd-token -n app-team1
kubectl create clusterrole deployment-clusterrole --verb=create --resource=deployment,statefulset,daemonset
#limted to the namespace app-team1。需要限制的是namespace级别，clusterrolebinding为设置全局，rolebinding正确
kubectl create rolebinding cicd-clusterrole --clusterrole=deployment-clusterrole --serviceaccount=app-team1:cicd-token

02 Task - 英文

Set the node named ek8s-node-1 as unavaliable and reschedule all the pods running on it.

kubectl cordon ek8s-node-1
kubectl drain ek8s-node-1 --delete-local-data --ignore-daemonsets --force

03 Task - 英文

Given an existing Kubernetes cluster running version 1.18.8，upgrade all of Kubernetes control plane and node components on the master node only to version 1.19.0。

You are also expected to upgrade kubelet and kubectl on the master node。

Be sure to drain the master node before upgrading it and uncordon it after the upgrade. Do not upgrade the worker nodes,etcd,the container manager,the CNI plugin,the DNS service or any other addons.

apt update
apt-cache policy kubeadm
apt-get update && apt-get install -y --allow-change-held-packages kubeadm=1.19.0
kubeadm version #检查kubeadm版本
kubectl drain master --ignore-daemonsets --delete-local-data --force #腾空控制平面节点
sudo kubeadm upgrade plan # 命令查看可升级的版本信息
sudo kubeadm upgrade apply v1.19.0 --etcd-upgrade=false #查看版本信息时，排除etcd从3.4.3-0升到3.4.7-0
kubectl uncordon master
sudo kubeadm upgrade node #升级其他控制面节点
apt-get update && apt-get install -y --allow-change-held-packages kubelet=1.19.0 kubectl=1.19.0
#升级其他控制面节点
sudo systemctl daemon-reload
sudo systemctl restart kubelet

04 Task - 中文

首先，为运行在https://127.0.0.1:2379 上的现有etcd 实例创建快照并将快照保存到/data/backup/etcd-snapshot.db。

为给定实例创建快照预计能在几秒钟内完成。如果该操作似乎挂起，则命令可能有问题。用ctrl+c 来取消操作，然后重试。

然后还原位于/var/data/etcd-snapshot-previous.db的现有先前快照。

提供了以下TLS证书和密钥，以通过etcdctl连接到服务器。

  • ca证书：/opt/KUIN00601/ca.crt
  • 客户端证书：/opt/KUIN00601/etcd-client.crt
  • 客户端密钥：/opt/KUIN00601/etcd-client.key

一定要把这参数用熟练，如果考试时有问题，不要急，多试试！！！

一旦正确配置了 etcd，只有具有有效证书的客户端才能访问它。要让 Kubernetes API 服务器访问，可以使用参数 --etcd-certfile=k8sclient.cert,–etcd-keyfile=k8sclient.key 和 --etcd-cafile=ca.cert 配置它。

我记得我考试进用的是：–certfile=/opt/KUIN00601/etcd-client.crt --我记得我考试进用的是：–certfile=/opt/KUIN00601/etcd-client.crt --keyfile=/opt/KUIN00601/etcd-client.key --cafile=/opt/KUIN00601/ca.crt

ETCDCTL_API=3 etcdctl --endpoint=https://127.0.0.1:2379 --certfile=/opt/KUIN00601/etcd-client.crt --keyfile=/opt/KUIN00601/etcd-client.key --cafile=/opt/KUIN00601/ca.crt snapshot save /data/backup/etcd-snapshot.db

ETCDCTL_API=3 etcdctl --endpoint=https://127.0.0.1:2379 --cert-file=/opt/KUIN00601/etcd-client.crt --key-file=/opt/KUIN00601/etcd-client.key --ca-file=/opt/KUIN00601/ca.crt snapshot restore /var/data/etcd-snapshot-previous.db

05 Task - 英文

Create a new NetworkPolicy named allow-port-from-namespace to allow Pods in the existing namespace internal to connect to port 8080 of other Pods in the same namespace. Ensure that the new NetworkPolicy:

  • does not allow access to Pods not listening on port 8080.
  • does not allow access from Pods not in namespace internal.
#network.yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-port-from-namespace
  namespace: internal
spec:
  podSelector:
    matchLabels: {}
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector: {}
    ports:
    - protocol: TCP
      port: 8080
#spec.podSelector限定了这个namespace里的pod可以访问
kubectl create -f network.yaml

06 Task - 英文

Reconfigure the existing deployment front-end and add a port specifiction named http exposing port 80/tcp of the existing container nginx.

Create a new service named front-end-svc exposing the container prot http.

Configure the new service to also expose the individual Pods via a NodePort on the nodes on which they are scheduled.

kubectl get deploy front-end
kubectl edit deploy front-end -o yaml
#port specification named http
#service.yaml
apiVersion: v1
kind: Service
metadata:
  name: front-end-svc
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    protocol: tcp
    name: http
  selector:
    app: nginx
  type: NodePort  
#
kubectl create -f service.yaml
#
kubectl get svc

#或者一条命令搞定,注意会遗漏port specification named http
kubectl expose deployment front-end --name=front-end-svc --port=80 --tarport=80 --type=NodePort

07 Task - 英文

Create a new nginx Ingress resource as follows:

  • Name: ping
  • Namespace: ing-internal
  • Exposing service hi on path /hi using service port 5678

The avaliability of service hi can be checked using the following command,which should return hi: curl -kL /hi

vi ingress.yaml
#
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ping
  namespace: ing-internal
spec:
  rules:
  - http:
      paths:
      - path: /hi
        pathType: Prefix
        backend:
          service:
            name: hi
            port:
              number: 5678
#              
kubectl create -f ingress.yaml

08 Task - 英文

Scale the deployment presentation to 3 pods.

kubectl get deployment
kubectl scale deployment.apps/presentation --replicas=3

09 Task - 英文

Task

Schedule a pod as follows:

  • name: nginx-kusc00401
  • Image: nginx
  • Node selector: disk-spinning
#yaml
apiVersion: v1
kind: Pod
metadata:
  name: nginx-kusc00401
spec:
  containers:
  - name: nginx
    image: nginx
    imagePullPolicy: IfNotPresent
  nodeSelector:
    disk: spinning
#    
kubectl create -f node-select.yaml

10 Task - 英文

Task Check to see how many nodes are ready (not including nodes tainted NoSchedule)and write the number to /opt/KUSC00402/kusc00402.txt.

kubectl describe nodes | grep ready|wc -l
kubectl describe nodes | grep -i taint | grep -i noschedule |wc -l
echo 3 > /opt/KUSC00402/kusc00402.txt

# 查询集群Ready节点数量
kubectl get node | grep -i ready |wc -l
# 找出节点taints、noSchedule
kubectl describe nodes | grep -i taints | grep -i noschedule |wc -l
#将得到的减数，写入到文件
echo 2 > /opt/KUSC00402/kusc00402.txt

11 Task - 英文

Create a pod named kucc8 with a single app container for each of the following images running inside (there may be between 1 and 4 images specified): nginx + redis + memcached + consul .

kubectl run kucc8 --image=nginx --dry-run -o yaml > kucc8.yaml
# vi kucc8.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  name: kucc8
spec:
  containers:
  - image: nginx
    name: nginx
  - image: redis
    name: redis
  - image: memcached
    name: memcached
  - image: consul
    name: consul
#    
kubectl create -f kucc8.yaml
#12.07

12 Task - 英文

Task Create a persistent volume whit name app-config, of capacity 1Gi and access mode ReadOnlyMany . the type of volume is hostPath and its location is /srv/app-config .

#vi pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: app-config
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadOnlyMany
  hostPath:
    path: /srv/app-config
#
kubectl create -f pv.yaml

13 Task - 英文

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.

vi pvc.yaml
#使用指定storageclass创建一个pvc
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pv-volume
spec:
  accessModes:
    - ReadWriteOnce
  volumeMode: Filesystem  
  resources:
    requests:
      storage: 10Mi
  storageClassName: csi-hostpath-sc

# vi pod-pvc.yaml
apiVersion: v1
kind: Pod
metadata:
  name: web-server
spec:
  containers:
    - name: web-server
      image: nginx
      volumeMounts:
      - mountPath: "/usr/share/nginx/html"
        name: my-volume
  volumes:
    - name: my-volume
      persistentVolumeClaim:
        claimName: pv-volume
# craete       
kubectl create -f pod-pvc.yaml
#edit 修改容量
kubectl edit pvc pv-volume --record

14 Task - 英文

Task Monitor the logs of pod bar and:

  • Extract log lines corresponding to error unable-to-access-website
  • Write them to /opt/KUTR00101/bar
kubectl logs bar | grep 'unable-to-access-website' > /opt/KUTR00101/bar
cat /opt/KUTR00101/bar

15 Task - 英文

Context Without changing its existing containers,an existing Pod needs to be integrated into Kubernetes’s build-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 busybox sidecar container to the existing Pod big-corp-app. The new sidecar container has to run the following command:

/bin/sh -c tail -n+1 -f /var/log/big-corp-app.log

Use a volume mount named logs to make the file /var/log/big-corp-app.log available to the sidecar container.

Don’t modify the existing container. Don’t modify the path of the log file,both containers must access it at /var/log/big-corp-app.log.

#
kubectl get pod big-corp-app -o yaml 
#
apiVersion: v1
kind: Pod
metadata:
  name: big-corp-app
spec:
  containers:
  - name: big-corp-app
    image: busybox
    args:
    - /bin/sh
    - -c
    - >
      i=0;
      while true;
      do
        echo "$(date) INFO $i" >> /var/log/big-corp-app.log;
        i=$((i+1));
        sleep 1;
      done
    volumeMounts:
    - name: logs
      mountPath: /var/log
  - name: count-log-1
    image: busybox
    args: [/bin/sh, -c, 'tail -n+1 -f /var/log/big-corp-app.log']
    volumeMounts:
    - name: logs
      mountPath: /var/log
  volumes:
  - name: logs
    emptyDir: {}

#验证：
kubectl logs big-corp-app -c count-log-1

16 Task - 英文

Form the pod label name-cpu-loader,find pods running high CPU workloads and write the name of the pod consuming most CPU to the file /opt/KUTR00401/KURT00401.txt(which alredy exists).

查看Pod标签为name=cpu-user-loader 的CPU使用率并且把cpu使用率最高的pod名称写入/opt/KUTR00401/KUTR00401.txt文件里

kubectl top pods -l name=name-cpu-loader --sort-by=cpu
echo '排名第一的pod名称' >>/opt/KUTR00401/KUTR00401.txt

17 Task - 英文

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.

Yon can ssh to teh failed node using:

ssh wk8s-node-o

You can assume elevated privileges on the node with the following command:

sudo -i

#名为wk8s-node-1 的节点处于NotReady状态，将其恢复成Ready状态，并且设置为开机自启
# 连接到NotReady节点
ssh wk8s-node-0
#获取权限
sudo -i
# 查看服务是否运行正常
systemctl status kubelet 
#如果服务非正常运行进行恢复
systemctl start kubelet
#设置开机自启
systemctl enable kubelet

18 Task - 英文

Task Set configuration context $kubectl config use-context k8s. Create a deployment as follows: Name: nginxapp Using container nginx with version 1.11.9-alpine. The deployment should contain 3 replicas. Next, deploy the app with new version 1.12.0-alpine by performing a rolling update and record that update.Finally,rollback that update to the previous version 1.11.9-alpine. 解析：部署deploy,然后修改进镜像（滚动更新），然后回滚上一版本

官网搜索Deployment

kubectl config use-context k8s  ##切换上下文
kubectl create deployment nginxapp --image=nginx:1.11.9-alpine  #启动一个deployment并设置镜像
kubectl scale deployment nginxapp --replicas=3  ##扩容为3个副本
kubectl set image deployment/nginxapp nginx=nginx:1.12.0-alpine --record=true #--record加上，现在这样就是滚动更新了
kubectl rollout history deployment/nginxapp #看下滚动历史
kubectl rollout undo deployment/nginxapp  ##执行回滚
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