Linux Foundation CKS 問題集

質問 1：
Use the kubesec docker images to scan the given YAML manifest, edit and apply the advised changes, and passed with a score of 4 points.
kubesec-test.yaml
apiVersion: v1
kind: Pod
metadata:
name: kubesec-demo
spec:
containers:
- name: kubesec-demo
image: gcr.io/google-samples/node-hello:1.0
securityContext:
readOnlyRootFilesystem: true
Hint: docker run -i kubesec/kubesec:512c5e0 scan /dev/stdin < kubesec-test.yaml
正解：
kubesec scan k8s-deployment.yaml
cat <<EOF > kubesec-test.yaml
apiVersion: v1
kind: Pod
metadata:
name: kubesec-demo
spec:
containers:
- name: kubesec-demo
image: gcr.io/google-samples/node-hello:1.0
securityContext:
readOnlyRootFilesystem: true
EOF
kubesec scan kubesec-test.yaml
docker run -i kubesec/kubesec:512c5e0 scan /dev/stdin < kubesec-test.yaml kubesec http 8080 &
[1] 12345
{"severity":"info","timestamp":"2019-05-12T11:58:34.662+0100","caller":"server/server.go:69","message":"Starting HTTP server on port 8080"} curl -sSX POST --data-binary @test/asset/score-0-cap-sys-admin.yml http://localhost:8080/scan
[
{
"object": "Pod/security-context-demo.default",
"valid": true,
"message": "Failed with a score of -30 points",
"score": -30,
"scoring": {
"critical": [
{
"selector": "containers[] .securityContext .capabilities .add == SYS_ADMIN",
"reason": "CAP_SYS_ADMIN is the most privileged capability and should always be avoided"
},
{
"selector": "containers[] .securityContext .runAsNonRoot == true",
"reason": "Force the running image to run as a non-root user to ensure least privilege"
},
// ...

質問 2：
Analyze and edit the given Dockerfile
FROM ubuntu:latest
RUN apt-get update -y
RUN apt-install nginx -y
COPY entrypoint.sh /
ENTRYPOINT ["/entrypoint.sh"]
USER ROOT
Fixing two instructions present in the file being prominent security best practice issues Analyze and edit the deployment manifest file apiVersion: v1 kind: Pod metadata:
name: security-context-demo-2
spec:
securityContext:
runAsUser: 1000
containers:
- name: sec-ctx-demo-2
image: gcr.io/google-samples/node-hello:1.0
securityContext:
runAsUser: 0
privileged: True
allowPrivilegeEscalation: false
Fixing two fields present in the file being prominent security best practice issues Don't add or remove configuration settings; only modify the existing configuration settings Whenever you need an unprivileged user for any of the tasks, use user test-user with the user id 5487
正解：
FROM debian:latest
MAINTAINER [email protected]
# 1 - RUN
RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -yq apt-utils RUN DEBIAN_FRONTEND=noninteractive apt-get install -yq htop RUN apt-get clean
# 2 - CMD
#CMD ["htop"]
#CMD ["ls", "-l"]
# 3 - WORKDIR and ENV
WORKDIR /root
ENV DZ version1
$ docker image build -t bogodevops/demo .
Sending build context to Docker daemon 3.072kB
Step 1/7 : FROM debian:latest
---> be2868bebaba
Step 2/7 : MAINTAINER [email protected]
---> Using cache
---> e2eef476b3fd
Step 3/7 : RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -yq apt-utils
---> Using cache
---> 32fd044c1356
Step 4/7 : RUN DEBIAN_FRONTEND=noninteractive apt-get install -yq htop
---> Using cache
---> 0a5b514a209e
Step 5/7 : RUN apt-get clean
---> Using cache
---> 5d1578a47c17
Step 6/7 : WORKDIR /root
---> Using cache
---> 6b1c70e87675
Step 7/7 : ENV DZ version1
---> Using cache
---> cd195168c5c7
Successfully built cd195168c5c7
Successfully tagged bogodevops/demo:latest

質問 3：
Create a User named john, create the CSR Request, fetch the certificate of the user after approving it.
Create a Role name john-role to list secrets, pods in namespace john
Finally, Create a RoleBinding named john-role-binding to attach the newly created role john-role to the user john in the namespace john. To Verify: Use the kubectl auth CLI command to verify the permissions.
正解：
se kubectl to create a CSR and approve it.
Get the list of CSRs:
kubectl get csr
Approve the CSR:
kubectl certificate approve myuser
Get the certificate
Retrieve the certificate from the CSR:
kubectl get csr/myuser -o yaml
here are the role and role-binding to give john permission to create NEW_CRD resource:
kubectl apply -f roleBindingJohn.yaml --as=john
rolebinding.rbac.authorization.k8s.io/john_external-rosource-rb created kind: RoleBinding apiVersion: rbac.authorization.k8s.io/v1 metadata:
name: john_crd
namespace: development-john
subjects:
- kind: User
name: john
apiGroup: rbac.authorization.k8s.io
roleRef:
kind: ClusterRole
name: crd-creation
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: crd-creation
rules:
- apiGroups: ["kubernetes-client.io/v1"]
resources: ["NEW_CRD"]
verbs: ["create, list, get"]

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：
Context
A Role bound to a Pod's ServiceAccount grants overly permissive permissions. Complete the following tasks to reduce the set of permissions.
Task
Given an existing Pod named web-pod running in the namespace security.
Edit the existing Role bound to the Pod's ServiceAccount sa-dev-1 to only allow performing watch operations, only on resources of type services.
Create a new Role named role-2 in the namespace security, which only allows performing update operations, only on resources of type namespaces.
Create a new RoleBinding named role-2-binding binding the newly created Role to the Pod's ServiceAccount.

正解：