ckad认证考题核心概念

核心概念（13%）

题1：创建命名空间与pod

题目：Create a namespace called 'mynamespace' and a pod with image nginx called nginx on this namespace

题解：

# 创建命令空间
kubectl create namespace mynamespace
# 使用命令创建nginx pod
kubectl run nginx --image=nginx -n mynamespace

题2：利用yaml创建pod

题目：Create the pod that was just described using YAML

题解：

# 使用yaml文件创建pod，两者都可以
kubectl create -f nginx_pod.yaml
# nginx_pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: nginx
  namespace: mynamespace
spec:
  containers:
  - name: nginx
    image: nginx
    
# 除了手敲yaml，官网复制，还可以命令生成
kubectl run nginx --image=nginx --dry-run=client -n mynamespace -o yaml > pod.yaml

题3：使用命令创建执行某一条命令的pod

题目：Create a busybox pod (using kubectl command) that runs the command "env". Run it and see the output

题解：

kubectl run busybox --image=busybox --command -- env
kubectl logs busybox

题4：使用yaml创建执行某一条命令的pod

题目：Create a busybox pod (using YAML) that runs the command "env". Run it and see the output

题解：

kubectl run busybox --image=busybox --command --dry-run=client -o yaml -- env > pod.yaml
# pod.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: busybox
  name: busybox
spec:
  containers:
  - command:
    - env
    image: busybox
    name: busybox
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

kubectl create -f pod.yaml

题5：获取创建命令空间的yaml，但不创建它

题目：Get the YAML for a new namespace called 'myns' without creating it

题解：

kubectl create namespace myns -o yaml --dry-run=client

apiVersion: v1
kind: Namespace
metadata:
  creationTimestamp: null
  name: myns
spec: {}
status: {}

题6：获取ResourceQuota 的yaml，但不创建它

题目：Get the YAML for a new ResourceQuota called 'myrq' with hard limits of 1 CPU, 1G memory and 2 pods without creating it

题解：

kubectl create quota myrq --hard=cpu=1,memory=1G,pods=2 --dry-run=client -o yaml

apiVersion: v1
kind: ResourceQuota
metadata:
  creationTimestamp: null
  name: myrq
spec:
  hard:
    cpu: "1"
    memory: 1G
    pods: "2
status: {}

题7：获取所有命名空间上的 pod

题目：Get pods on all namespaces

题解：

kubectl get po -A

题8：创建pod并开发端口

题目：Create a pod with image nginx called nginx and expose traffic on port 80

题解：

kubectl run nginx --image=nginx --port=80

题9：修改pod的镜像，并观察pod

题目：Change pod's image to nginx:1.7.1. Observe that the container will be restarted as soon as the image gets pulled

题解：

kubectl set image pod/nginx nginx=nginx:1.7.1
kubectl describe po nginx 
kubectl get po nginx -w 

# 也可以使用kubectl edit 修改yaml中的images值

题10：获取nginx pod的ip

题目：Get nginx pod's ip created in previous step

题解：

kubectl get po -o wide | grep nginx
# 可以使用awk取ip，不过做题的时候没必要

题11：创建临时pod访问nginx镜像

题目：use a temp busybox image to wget its '/'

题解：

kubectl run busybox --image=busybox --rm -it -- wget -O- {nginx pod的ip}:80

题12：获取pod的yaml

题目：Get pod's YAML

题解：

kubectl get po nginx -o yaml

题13：获取有关 pod 的信息，包括有关潜在问题

题目：Get information about the pod, including details about potential issues (e.g. pod hasn't started)

题解：

kubectl describe po nginx

题14：获取pod的日志

题目：Get pod logs

题解：

kubectl logs nginx

题15：如果 pod 崩溃并重新启动，则获取有关前一个实例的日志

题目：If pod crashed and restarted, get logs about the previous instance

题解：

kubectl logs nginx -p

题16：在pod中执行命令

题目：Execute a simple shell on the nginx pod

题解：

kubectl exec -it nginx -- /bin/sh

题17：创建一个执行一条命令的pod

题目：Create a busybox pod that echoes 'hello world' and then exits

题解：

kubectl run busybox --image=busybox -it -- echo 'hello world'

题18：同17，但创建的是临时pod

题目：Do the same, but have the pod deleted automatically when it's completed

题解：

kubectl run busybox --image=busybox -it --rm -- /bin/sh -c 'echo hello world'

题19：创建一个pod，并设置env

题目：Create an nginx pod and set an env value as 'var1=val1'. Check the env value existence within the pod

题解：

# 创建
kubectl run nginx --image=nginx --restart=Never --env=var1=val1
# 检查
kubectl exec -it nginx -- env