CKA考证

考试报名时间是今年的7月1，拿证时间7月25。因为现在工作中常用到Kubernetes，所以就考虑报了一个CKA，费用2498。有优惠券，可以自己网上查一下。平常写yaml文件，都是查的官网kubernetes.io。不建议不刷题直接考试，之前可以使用本地的Google浏览器保存一些标签，现在改成了官网要求下载的PSI。考试中的一切操作都在这个PSI中。(PSI在Take Exam里面会提示下载和程序包，300M大小)

Take Exam，在预约考试前30分钟变成可点击状态，这里一定要尽快进去验证，准备好清晰度高一些的摄像头、身份证、信用卡或者护照。摄像头如果在检查途中掉了，会直接退出，又得从PSI进入，重新之前的检查操作了。这个过程会要求检查周围环境、桌面环境、个人信息、手上穿戴。要求周围不能有人，桌上不能放东西等等。尽量在考前30分钟就全部准备好，这样更快进入考试。 在预约的考试时间的前30分钟内，要把信息都验证好。如果到了预约的考试时间还没进入考试界面，会提示考试已经结束。这样就要重新预约时间了，次数会扣掉，可以发邮件给官方([email protected])，让他们把次数加回来，一共有两次机会。

PSI界面-考试操作环境 在这个窗口中，左边是题目，右边是提供的一个带界面的ubuntu操作系统，建议整个大点的显示器。 这个里面带的浏览器，有延迟，不好用，而且那个窗口滚动条也细，不好控制，建议网络好的情况下考试。左边有直达官网的链接，每个题目都有，比如PVC,POD,NODE，都会给链接直达官网（不需要文档辅助的大佬可以忽略~~）

真实考题只有17-20题，题目类型都在下面这些题型中囊括了，题目解答放在单独的一篇文档中

Task weight: 1% You have access to multiple clusters from your main terminal through kubectl contexts. Write all those context names into /opt/course/1/contexts. Next write a command to display the current context into /opt/course/1/context_default_kubectl.sh, the command should use kubectl. Finally write a second command doing the same thing into /opt/course/1/context_default_no_kubectl.sh, but without the use of kubectl.

Task weight: 3% Use context: kubectl config use-context k8s-c1-H Create a single Pod of image httpd:2.4.41-alpine in Namespace default. The Pod should be named pod1 and the container should be named pod1-container. This Pod should only be scheduled on a master node, do not add new labels any nodes. Shortly write the reason on why Pods are by default not scheduled on master nodes into /opt/course/2/master_schedule_reason .

Task weight: 1% Use context: kubectl config use-context k8s-c1-H There are two Pods named o3db-* in Namespace project-c13. C13 management asked you to scale the Pods down to one replica to save resources. Record the action.

Task weight: 4% Use context: kubectl config use-context k8s-c1-H Do the following in Namespace default. Create a single Pod named ready-if-service-ready of image nginx:1.16.1-alpine. Configure a LivenessProbe which simply runs true. Also configure a ReadinessProbe which does check if the url http://service-am-i-ready:80 is reachable, you can use wget -T2 -O- http://service-am-i-ready:80 for this. Start the Pod and confirm it isn’t ready because of the ReadinessProbe. Create a second Pod named am-i-ready of image nginx:1.16.1-alpine with label id: cross-server-ready. The already existing Service service-am-i-ready should now have that second Pod as endpoint. Now the first Pod should be in ready state, confirm that.

Task weight: 1% Use context: kubectl config use-context k8s-c1-H There are various Pods in all namespaces. Write a command into /opt/course/5/find_pods.sh which lists all Pods sorted by their AGE (metadata.creationTimestamp). Write a second command into /opt/course/5/find_pods_uid.sh which lists all Pods sorted by field metadata.uid. Use kubectl sorting for both commands.

Task weight: 8% Use context: kubectl config use-context k8s-c1-H Create a new PersistentVolume named safari-pv. It should have a capacity of 2Gi, accessMode ReadWriteOnce, hostPath /Volumes/Data and no storageClassName defined. Next create a new PersistentVolumeClaim in Namespace project-tiger named safari-pvc . It should request 2Gi storage, accessMode ReadWriteOnce and should not define a storageClassName. The PVC should bound to the PV correctly. Finally create a new Deployment safari in Namespace project-tiger which mounts that volume at /tmp/safari-data. The Pods of that Deployment should be of image httpd:2.4.41-alpine.

Task weight: 1% Use context: kubectl config use-context k8s-c1-H The metrics-server hasn’t been installed yet in the cluster, but it’s something that should be done soon. Your college would already like to know the kubectl commands to: show node resource usage show Pod and their containers resource usage Please write the commands into /opt/course/7/node.sh and /opt/course/7/pod.sh.

Task weight: 2% Use context: kubectl config use-context k8s-c1-H Ssh into the master node with ssh cluster1-master1. Check how the master components kubelet, kube-apiserver, kube-scheduler, kube-controller-manager and etcd are started/installed on the master node. Also find out the name of the DNS application and how it’s started/installed on the master node. Write your findings into file /opt/course/8/master-components.txt. The file should be structured like: /opt/course/8/master-components.txt kubelet: [TYPE] kube-apiserver: [TYPE] kube-scheduler: [TYPE] kube-controller-manager: [TYPE] etcd: [TYPE] dns: [TYPE] [NAME]

Choices of [TYPE] are: not-installed, process, static-pod, pod

Task weight: 5% Use context: kubectl config use-context k8s-c2-AC Ssh into the master node with ssh cluster2-master1. Temporarily stop the kube-scheduler, this means in a way that you can start it again afterwards. Create a single Pod named manual-schedule of image httpd:2.4-alpine, confirm its created but not scheduled on any node. Now you’re the scheduler and have all its power, manually schedule that Pod on node cluster2-master1. Make sure it’s running. Start the kube-scheduler again and confirm its running correctly by creating a second Pod named manual-schedule2 of image httpd:2.4-alpine and check if it’s running on cluster2-worker1.

Task weight: 6%Use context: kubectl config use-context k8s-c1-HCreate a new ServiceAccount processor in Namespace project-hamster. Create a Role and RoleBinding, both named processor as well. These should allow the new SA to only create Secrets and ConfigMaps in that Namespace.

Task weight: 4% Use context: kubectl config use-context k8s-c1-H Use Namespace project-tiger for the following. Create a DaemonSet named ds-important with image httpd:2.4-alpine and labels id=ds-important and uuid=18426a0b-5f59-4e10-923f-c0e078e82462. The Pods it creates should request 10 millicore cpu and 10 mebibyte memory. The Pods of that DaemonSet should run on all nodes, master and worker.

Task weight: 6% Use context: kubectl config use-context k8s-c1-H Use Namespace project-tiger for the following. Create a Deployment named deploy-important with label id=very-important (the Pods should also have this label) and 3 replicas. It should contain two containers, the first named container1 with image nginx:1.17.6-alpine and the second one named container2 with image kubernetes/pause. There should be only ever one Pod of that Deployment running on one worker node. We have two worker nodes: cluster1-worker1 and cluster1-worker2. Because the Deployment has three replicas the result should be that on both nodes one Pod is running. The third Pod won’t be scheduled, unless a new worker node will be added. In a way we kind of simulate the behaviour of a DaemonSet here, but using a Deployment and a fixed number of replicas.

Task weight: 4% Use context: kubectl config use-context k8s-c1-H Create a Pod named multi-container-playground in Namespace default with three containers, named c1, c2 and c3. There should be a volume attached to that Pod and mounted into every container, but the volume shouldn’t be persisted or shared with other Pods. Container c1 should be of image nginx:1.17.6-alpine and have the name of the node where its Pod is running available as environment variable MY_NODE_NAME. Container c2 should be of image busybox:1.31.1 and write the output of the date command every second in the shared volume into file date.log. You can use while true; do date >> /your/vol/path/date.log; sleep 1; done for this. Container c3 should be of image busybox:1.31.1 and constantly send the content of file date.log from the shared volume to stdout. You can use tail -f /your/vol/path/date.log for this. Check the logs of container c3 to confirm correct setup.

Task weight: 2% Use context: kubectl config use-context k8s-c1-H You’re ask to find out following information about the cluster k8s-c1-H : How many master nodes are available? How many worker nodes are available? What is the Service CIDR? Which Networking (or CNI Plugin) is configured and where is its config file? Which suffix will static pods have that run on cluster1-worker1? Write your answers into file /opt/course/14/cluster-info, structured like this: /opt/course/14/cluster-info 1: [ANSWER] 2: [ANSWER] 3: [ANSWER] 4: [ANSWER] 5: [ANSWER]

Task weight: 3% Use context: kubectl config use-context k8s-c2-AC Write a command into /opt/course/15/cluster_events.sh which shows the latest events in the whole cluster, ordered by time. Use kubectl for it. Now kill the kube-proxy Pod running on node cluster2-worker1 and write the events this caused into /opt/course/15/pod_kill.log. Finally kill the containerd container of the kube-proxy Pod on node cluster2-worker1 and write the events into /opt/course/15/container_kill.log. Do you notice differences in the events both actions caused?

Task weight: 2% Use context: kubectl config use-context k8s-c1-H Create a new Namespace called cka-master. Write the names of all namespaced Kubernetes resources (like Pod, Secret, ConfigMap…) into /opt/course/16/resources.txt. Find the project-* Namespace with the highest number of Roles defined in it and write its name and amount of Roles into /opt/course/16/crowded-namespace.txt.

Task weight: 3%Use context: kubectl config use-context k8s-c1-HIn Namespace project-tiger create a Pod named tigers-reunite of image httpd:2.4.41-alpine with labels pod=container and container=pod. Find out on which node the Pod is scheduled. Ssh into that node and find the containerd container belonging to that Pod.Using command crictl:Write the ID of the container and the info.runtimeType into /opt/course/17/pod-container.txtWrite the logs of the container into /opt/course/17/pod-container.log

Task weight: 8% Use context: kubectl config use-context k8s-c3-CCC There seems to be an issue with the kubelet not running on cluster3-worker1. Fix it and confirm that cluster has node cluster3-worker1 available in Ready state afterwards. You should be able to schedule a Pod on cluster3-worker1 afterwards. Write the reason of the issue into /opt/course/18/reason.txt.

Task weight: 3% this task can only be solved if questions 18 or 20 have been successfully implemented and the k8s-c3-CCC cluster has a functioning worker node Use context: kubectl config use-context k8s-c3-CCC Do the following in a new Namespace secret. Create a Pod named secret-pod of image busybox:1.31.1 which should keep running for some time, it should be able to run on master nodes as well. There is an existing Secret located at /opt/course/19/secret1.yaml, create it in the secret Namespace and mount it readonly into the Pod at /tmp/secret1. Create a new Secret in Namespace secret called secret2 which should contain user=user1 and pass=1234. These entries should be available inside the Pod’s container as environment variables APP_USER and APP_PASS. Confirm everything is working.

Task weight: 10% Use context: kubectl config use-context k8s-c3-CCC Your coworker said node cluster3-worker2 is running an older Kubernetes version and is not even part of the cluster. Update Kubernetes on that node to the exact version that’s running on cluster3-master1. Then add this node to the cluster. Use kubeadm for this.

Task weight: 2% Use context: kubectl config use-context k8s-c3-CCC Create a Static Pod named my-static-pod in Namespace default on cluster3-master1. It should be of image nginx:1.16-alpine and have resource requests for 10m CPU and 20Mi memory. Then create a NodePort Service named static-pod-service which exposes that static Pod on port 80 and check if it has Endpoints and if its reachable through the cluster3-master1 internal IP address. You can connect to the internal node IPs from your main terminal.

Task weight: 2% Use context: kubectl config use-context k8s-c2-AC Check how long the kube-apiserver server certificate is valid on cluster2-master1. Do this with openssl or cfssl. Write the exipiration date into /opt/course/22/expiration. Also run the correct kubeadm command to list the expiration dates and confirm both methods show the same date. Write the correct kubeadm command that would renew the apiserver server certificate into /opt/course/22/kubeadm-renew-certs.sh.

Task weight: 2% Use context: kubectl config use-context k8s-c2-AC Node cluster2-worker1 has been added to the cluster using kubeadm and TLS bootstrapping. Find the “Issuer” and “Extended Key Usage” values of the cluster2-worker1: kubelet client certificate, the one used for outgoing connections to the kube-apiserver. kubelet server certificate, the one used for incoming connections from the kube-apiserver. Write the information into file /opt/course/23/certificate-info.txt. Compare the “Issuer” and “Extended Key Usage” fields of both certificates and make sense of these.

Task weight: 9% Use context: kubectl config use-context k8s-c1-H There was a security incident where an intruder was able to access the whole cluster from a single hacked backend Pod. To prevent this create a NetworkPolicy called np-backend in Namespace project-snake. It should allow the backend-* Pods only to: connect to db1-* Pods on port 1111 connect to db2-* Pods on port 2222 Use the app label of Pods in your policy. After implementation, connections from backend-* Pods to vault-* Pods on port 3333 should for example no longer work.

Task weight: 8% Use context: kubectl config use-context k8s-c3-CCC Make a backup of etcd running on cluster3-master1 and save it on the master node at /tmp/etcd-backup.db. Then create a Pod of your kind in the cluster. Finally restore the backup, confirm the cluster is still working and that the created Pod is no longer with us.

Use context: kubectl config use-context k8s-c1-H Check all available Pods in the Namespace project-c13 and find the names of those that would probably be terminated first if the Nodes run out of resources (cpu or memory) to schedule all Pods. Write the Pod names into /opt/course/e1/pods-not-stable.txt.

Use context: kubectl config use-context k8s-c1-H There is an existing ServiceAccount secret-reader in Namespace project-hamster. Create a Pod of image curlimages/curl:7.65.3 named tmp-api-contact which uses this ServiceAccount. Make sure the container keeps running. Exec into the Pod and use curl to access the Kubernetes Api of that cluster manually, listing all available secrets. You can ignore insecure https connection. Write the command(s) for this into file /opt/course/e4/list-secrets.sh.

Use context: kubectl config use-context k8s-c2-AC The cluster admin asked you to find out the following information about etcd running on cluster2-master1: Server private key location Server certificate expiration date Is client certificate authentication enabled Write these information into /opt/course/p1/etcd-info.txt Finally you’re asked to save an etcd snapshot at /etc/etcd-snapshot.db on cluster2-master1 and display its status.

Use context: kubectl config use-context k8s-c1-H You’re asked to confirm that kube-proxy is running correctly on all nodes. For this perform the following in Namespace project-hamster: Create a new Pod named p2-pod with two containers, one of image nginx:1.21.3-alpine and one of image busybox:1.31. Make sure the busybox container keeps running for some time. Create a new Service named p2-service which exposes that Pod internally in the cluster on port 3000->80. Find the kube-proxy container on all nodes cluster1-master1, cluster1-worker1 and cluster1-worker2 and make sure that it’s using iptables. Use command crictl for this. Write the iptables rules of all nodes belonging the created Service p2-service into file /opt/course/p2/iptables.txt. Finally delete the Service and confirm that the iptables rules are gone from all nodes.

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.