CKA 真题

# 题目一般都是按名字排序

$ kubectl get pod --sort-by .metadata.name

# 要求是把错误内容输出到某个文件中，可以粘贴，也可以直接重定向文件

$ kubectl logs mypod-798fcd9949-lk9rc | grep error > xx.log

$ cat > pod.yaml << EOF
apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
    env: test
spec:
  containers:
  - name: nginx
    image: nginx
    imagePullPolicy: IfNotPresent
  nodeSelector:
    disktype: ssd
EOF

$ kubectl create -f pod.yaml

$ kubectl get node | grep -w Ready

apiVersion: v1
kind: Pod
metadata:
  name: test-pd
spec:
  containers:
  - image: k8s.gcr.io/test-webserver
    name: test-container
    volumeMounts:
    - mountPath: /cache
      name: cache-volume
  volumes:
  - name: cache-volume
    emptyDir: {}

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: nginx-pod
  name: nginx-pod
spec:
  containers:
  - image: nginx
    name: nginx-pod
    command: ['sh','-c','if [ -f "a.txt" ]; then  echo xx ;fi']
    ports:
    - containerPort: 80
    resources: {}
    volumeMounts:
    - name: workdir
      mountPath: /usr/nginx/html
  dnsPolicy: ClusterFirst
  initContainers:
  - image: busybox
    name: initcheck
    command: ['sh','-c','touch /tmp/index.html']
    volumeMounts:
    - name: workdir
      mountPath: /tmp
  volumes:
  - name: workdir
    emptyDir: {}

apiVersion: v1
kind: Pod
metadata:
  name: nats
  labels:
    app: nats
spec:
  containers:
    - name: nats
      image: nats

---
apiVersion: v1
kind: Service
metadata:
  name: nats
spec:
  selector:
    app: nats
  ports:
    - port: 4222
      nodePort: 32222
  type: NodePort

apiVersion: v1
kind: Pod
metadata:
  name: demo
spec:
  containers:
  - image: nginx
    name: nginx
  - image: redis
    name: redis

$ kubectl top pods --selector="app=demo" | grep -v NAME | sort -k 2 -nr

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: fluentd-elasticsearch
  namespace: kube-system
  labels:
    k8s-app: fluentd-logging
spec:
  selector:
    matchLabels:
      name: fluentd-elasticsearch
  template:
    metadata:
      labels:
        name: fluentd-elasticsearch
    spec:
      tolerations:
      # this toleration is to have the daemonset runnable on master nodes
      # remove it if your masters can't run pods
      - key: node-role.kubernetes.io/master
        effect: NoSchedule
      containers:
      - name: fluentd-elasticsearch
        image: quay.io/fluentd_elasticsearch/fluentd:v2.5.2
        resources:
          limits:
            memory: 200Mi
          requests:
            cpu: 100m
            memory: 200Mi
        volumeMounts:
        - name: varlog
          mountPath: /var/log
        - name: varlibdockercontainers
          mountPath: /var/lib/docker/containers
          readOnly: true
      terminationGracePeriodSeconds: 30
      volumes:
      - name: varlog
        hostPath:
          path: /var/log
      - name: varlibdockercontainers
        hostPath:
          path: /var/lib/docker/containers

$ kubectl scale --replicas=4 deployment demo

$ echo -n 'admin' | base64

YWRtaW4=

$ echo -n '1f2d1e2e67df' | base64

MWYyZDFlMmU2N2Rm

apiVersion: v1
kind: Secret
metadata:
  name: mysecret
type: Opaque
data:
  username: YWRtaW4=
  password: MWYyZDFlMmU2N2Rm

$ kubectl apply -f ./secret.yaml

apiVersion: v1
kind: Pod
metadata:
  name: secret-env-pod
spec:
  containers:
  - name: mycontainer
    image: redis
    env:
      - name: SECRET_USERNAME
        valueFrom:
          secretKeyRef:
            name: mysecret
            key: username
      - name: SECRET_PASSWORD
        valueFrom:
          secretKeyRef:
            name: mysecret
            key: password
  restartPolicy: Never

apiVersion: v1
kind: Pod
metadata:
  name: mypod
spec:
  containers:
  - name: mypod
    image: redis
    volumeMounts:
    - name: foo
      mountPath: "/etc/foo"
      readOnly: true
  volumes:
  - name: foo
    secret:
      secretName: mysecret

$ kubectl set image deployments demo demo=nginx:1.11 --record

$ kubectl rollout undo deployment demo

# 查看 dns
$ kubectl run -it --image busybox:1.28.4  dnstest --rm /bin/sh

# 查看 sevice
$ nslookup svc-demo.kube-system.svc.cluster.local

# 查看 pod
# 查看pod ip时，要把1.2.3.4换成1-2-3-4，否则会报错
$ nslookup 1-2-3-4.default.pod.cluster.local

# 先声明环境变量ETCDCTL_API=3 ，不然etcdctl 是v2版本
$ ETCDCTL_API=3 etcdctl --cacert=/opt/kubernetes/ssl/ca.pem --cert=/opt/kubernetes/ssl/server.pem --key=/opt/kubernetes/ssl/server-key.pem --endpoints=https://192.168.1.36:2379 snapshot save /data/etcd_backup_dir/etcd-snapshot-`date +%Y%m%d`.db

apiVersion: v1
kind: Pod
metadata:
  name: static-web
  labels:
    role: myrole
spec:
  containers:
    - name: web
      image: nginx
      ports:
        - name: web
          containerPort: 80
          protocol: TCP

# 创建 ns
$ kubectl create namespace test

apiVersion: v1
kind: Pod
metadata:
  name: demo
  namespace: test
spec:
  containers:
  - image: nginx
    name: nginx

apiVersion: v1
kind: PersistentVolume
metadata:
  name: example-pv
spec:
  capacity:
    storage: 1Gi
  volumeMode: Filesystem
  accessModes:
  - ReadOnlyMany
  persistentVolumeReclaimPolicy: Delete
  local:
    path: /data
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: kubernetes.io/hostname
          operator: In
          values:
          - test-node

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  containers:
  - name: nginx
    image: nginx
    imagePullPolicy: IfNotPresent

apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    protocol: TCP
  selector:
    app: nginx

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
    env: test
spec:
  containers:
  - name: nginx
    image: nginx
    imagePullPolicy: IfNotPresent
  nodeSelector:
    disktype: ssd

$ kubectl drain ${node-name} --delete-local-data=true --ignore-daemonsets=true