Linux Foundation CKS 問題集

質問 1：
Context: Cluster: prod Master node: master1 Worker node: worker1
You can switch the cluster/configuration context using the following command:
[desk@cli] $ kubectl config use-context prod
Task: Analyse and edit the given Dockerfile (based on the ubuntu:18:04 image) /home/cert_masters/Dockerfile fixing two instructions present in the file being prominent security/best-practice issues.
Analyse and edit the given manifest file /home/cert_masters/mydeployment.yaml fixing two fields present in the file being prominent security/best-practice issues.
Note: Don't add or remove configuration settings; only modify the existing configuration settings, so that two configuration settings each are no longer security/best-practice concerns. Should you need an unprivileged user for any of the tasks, use user nobody with user id 65535
正解：
1. For Dockerfile: Fix the image version & user name in Dockerfile 2. For mydeployment.yaml : Fix security contexts Explanation
[desk@cli] $ vim /home/cert_masters/Dockerfile
FROM ubuntu:latest # Remove this
FROM ubuntu:18.04 # Add this
USER root # Remove this
USER nobody # Add this
RUN apt get install -y lsof=4.72 wget=1.17.1 nginx=4.2
ENV ENVIRONMENT=testing
USER root # Remove this
USER nobody # Add this
CMD ["nginx -d"]

[desk@cli] $ vim /home/cert_masters/mydeployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
creationTimestamp: null
labels:
app: kafka
name: kafka
spec:
replicas: 1
selector:
matchLabels:
app: kafka
strategy: {}
template:
metadata:
creationTimestamp: null
labels:
app: kafka
spec:
containers:
- image: bitnami/kafka
name: kafka
volumeMounts:
- name: kafka-vol
mountPath: /var/lib/kafka
securityContext:
{"capabilities":{"add":["NET_ADMIN"],"drop":["all"]},"privileged": True,"readOnlyRootFilesystem": False, "runAsUser": 65535} # Delete This
{"capabilities":{"add":["NET_ADMIN"],"drop":["all"]},"privileged": False,"readOnlyRootFilesystem": True, "runAsUser": 65535} # Add This resources: {} volumes:
- name: kafka-vol
emptyDir: {}
status: {}
Pictorial View: [desk@cli] $ vim /home/cert_masters/mydeployment.yaml


質問 2：
Context
The kubeadm-created cluster's Kubernetes API server was, for testing purposes, temporarily configured to allow unauthenticated and unauthorized access granting the anonymous user duster-admin access.
Task
Reconfigure the cluster's Kubernetes API server to ensure that only authenticated and authorized REST requests are allowed.
Use authorization mode Node,RBAC and admission controller NodeRestriction.
Cleaning up, remove the ClusterRoleBinding for user system:anonymous.


正解：






質問 3：
Context
This cluster uses containerd as CRI runtime.
Containerd's default runtime handler is runc. Containerd has been prepared to support an additional runtime handler, runsc (gVisor).
Task
Create a RuntimeClass named sandboxed using the prepared runtime handler named runsc.
Update all Pods in the namespace server to run on gVisor.

正解：










質問 4：
Task
Create a NetworkPolicy named pod-access to restrict access to Pod users-service running in namespace dev-team.
Only allow the following Pods to connect to Pod users-service:


正解：





質問 5：
Cluster: scanner Master node: controlplane Worker node: worker1
You can switch the cluster/configuration context using the following command:
[desk@cli] $ kubectl config use-context scanner
Given: You may use Trivy's documentation.
Task: Use the Trivy open-source container scanner to detect images with severe vulnerabilities used by Pods in the namespace nato.
Look for images with High or Critical severity vulnerabilities and delete the Pods that use those images. Trivy is pre-installed on the cluster's master node. Use cluster's master node to use Trivy.
正解：