CKA 模拟真题 Killer.sh | Preview Question 3

Use context: kubectl config use-context k8s-c2-AC

Create a Pod named check-ip in Namespace default using image httpd:2.4.41-alpine . Expose it on port 80 as a ClusterIP Service named check-ip-service . Remember/output the IP of that Service.

Change the Service CIDR to 11.96.0.0/12 for the cluster.

Then create a second Service named check-ip-service2 pointing to the same Pod to check if your settings did take effect. Finally check if the IP of the first Service has changed.

译文

在命名空间default创建一个名为 check-ip 的Pod, 镜像使用 httpd:2.4.41-alpine 。将其作为一个名为 check-ip-service 的ClusterIP服务暴露在80端口。记住/output该服务的IP。

将集群的CIDR更改为 11.96.0.0/12 。

然后创建第二个名为 check-ip-service2 的服务，指向同一个Pod，检查你的设置是否生效。最后检查第一个服务的IP是否有变化。

解答

kubectl config use-context k8s-c2-AC

创建一个pod,并且暴露端口

k run check-ip --image=httpd:2.4.41-alpine

k expose pod check-ip --name check-ip-service --port 80

检查pod和service的IP

k get svc,ep -l run=check-ip

更改service的CIDR

ssh cluster2-controlplane1

root@cluster2-controlplane1:~# vim /etc/kubernetes/manifests/kube-apiserver.yaml

kube-apiserver.yaml

# /etc/kubernetes/manifests/kube-apiserver.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    component: kube-apiserver
    tier: control-plane
  name: kube-apiserver
  namespace: kube-system
spec:
  containers:
  - command:
    - kube-apiserver
    - --advertise-address=192.168.100.21
...
    - --service-account-key-file=/etc/kubernetes/pki/sa.pub
    - --service-cluster-ip-range=11.96.0.0/12             # change
    - --tls-cert-file=/etc/kubernetes/pki/apiserver.crt
    - --tls-private-key-file=/etc/kubernetes/pki/apiserver.key

编辑调度器配置文件

root@cluster2-controlplane1:~# vim /etc/kubernetes/manifests/kube-controller-manager.yaml

kube-controller-manager.yaml

# /etc/kubernetes/manifests/kube-controller-manager.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    component: kube-controller-manager
    tier: control-plane
  name: kube-controller-manager
  namespace: kube-system
spec:
  containers:
  - command:
    - kube-controller-manager
    - --allocate-node-cidrs=true
    - --authentication-kubeconfig=/etc/kubernetes/controller-manager.conf
    - --authorization-kubeconfig=/etc/kubernetes/controller-manager.conf
    - --bind-address=127.0.0.1
    - --client-ca-file=/etc/kubernetes/pki/ca.crt
    - --cluster-cidr=10.244.0.0/16
    - --cluster-name=kubernetes
    - --cluster-signing-cert-file=/etc/kubernetes/pki/ca.crt
    - --cluster-signing-key-file=/etc/kubernetes/pki/ca.key
    - --controllers=*,bootstrapsigner,tokencleaner
    - --kubeconfig=/etc/kubernetes/controller-manager.conf
    - --leader-elect=true
    - --node-cidr-mask-size=24
    - --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt
    - --root-ca-file=/etc/kubernetes/pki/ca.crt
    - --service-account-private-key-file=/etc/kubernetes/pki/sa.key
    - --service-cluster-ip-range=11.96.0.0/12         # change
    - --use-service-account-credentials=true

使用crictl检查api-server和调度器是否重启

root@cluster2-controlplane1:~# crictl ps | grep scheduler

检查已存在的pod和service的IP,发现没有发生变化

k get pod,svc -l run=check-ip

check-ip-0

创建第二个pod,并检查,发现IP已经改变

k expose pod check-ip --name check-ip-service2 --port 80
k get svc,ep -l run=check-ip

check-ip-1