最新的Linux Foundation Certified Kubernetes Security Specialist (CKS) - CKS免費考試真題

See the Explanation below for complete solution
Explanation:
1) Connect to the correct host
ssh cks000028
sudo -i
(If hostname differs in your exam, use the one shown in the question banner.)
2) Edit the API server static pod manifest
API server is a static pod in kubeadm.
vi /etc/kubernetes/manifests/kube-apiserver.yaml
3) Configure API server to enable auditing
Inside the command: section, ensure ALL of the following flags exist
(add them if missing, modify if present).
3.1 Use the given audit policy file
- --audit-policy-file=/etc/kubernetes/logpolicy/audit-policy.yaml
3.2 Store audit logs at the required location
- --audit-log-path=/var/log/kubernetes/audit-logs.txt
3.3 Retain a maximum of 2 log files
- --audit-log-maxbackup=2
3.4 Retain logs for 10 days
- --audit-log-maxage=10
✅ Example (your file may have more flags - that's fine):
- command:
- kube-apiserver
- --audit-policy-file=/etc/kubernetes/logpolicy/audit-policy.yaml
- --audit-log-path=/var/log/kubernetes/audit-logs.txt
- --audit-log-maxbackup=2
- --audit-log-maxage=10
Save and exit:
:wq
The API server will auto-restart (static pod).
Optional quick check:
docker ps | grep kube-apiserver
4) Edit and EXTEND the audit policy
Open the given basic policy:
vi /etc/kubernetes/logpolicy/audit-policy.yaml
The file already contains rules for what NOT to log.
You must ADD rules BELOW them (do not delete existing ones).
5) Add the required audit rules (EXACT ORDER)
Append the following rules in this order (order matters in audit policies).
5.1 Log namespaces interactions at RequestResponse
- level: RequestResponse
resources:
- group: ""
resources: ["namespaces"]
5.2 Log deployment request bodies in namespace webapps
- level: RequestResponse
namespaces: ["webapps"]
resources:
- group: "apps"
resources: ["deployments"]
5.3 Log ConfigMap and Secret interactions (all namespaces) at Metadata
- level: Metadata
resources:
- group: ""
resources: ["configmaps", "secrets"]
5.4 Log all other requests at Metadata
This must be LAST
- level: Metadata
5.5 Final audit-policy.yaml should END like this
# (existing "do not log" rules above)
- level: RequestResponse
resources:
- group: ""
resources: ["namespaces"]
- level: RequestResponse
namespaces: ["webapps"]
resources:
- group: "apps"
resources: ["deployments"]
- level: Metadata
resources:
- group: ""
resources: ["configmaps", "secrets"]
- level: Metadata
Save and exit:
:wq
6) Make sure API server uses the EXTENDED policy
Touch the manifest to guarantee reload:
touch /etc/kubernetes/manifests/kube-apiserver.yaml
Wait a few seconds.
7) Verify auditing is working
7.1 Check audit log file exists
ls -l /var/log/kubernetes/audit-logs.txt
7.2 Generate test activity
kubectl get namespaces
kubectl get configmaps -A
7.3 Confirm logs are written
tail -n 20 /var/log/kubernetes/audit-logs.txt
You should see audit entries.

See the Explanation belowExplanation:
ETCD secret encryption can be verified with the help of etcdctl command line utility.
ETCD secrets are stored at the path /registry/secrets/$namespace/$secret on the master node.
The below command can be used to verify if the particular ETCD secret is encrypted or not.
# ETCDCTL_API=3 etcdctl get /registry/secrets/default/secret1 [...] | hexdump -C

See the Explanation below
Explanation:
worker1 $ vim /var/lib/kubelet/config.yaml
anonymous:
enabled: true #Delete this
enabled: false #Replace by this
authorization:
mode: AlwaysAllow #Delete this
mode: Webhook #Replace by this
worker1 $ systemctl restart kubelet. # To reload kubelet config
ssh to master1
master1 $ vim /etc/kubernetes/manifests/kube-apiserver.yaml
- -- authorization-mode=Node,RBAC
master1 $ vim /etc/kubernetes/manifests/etcd.yaml
- --client-cert-auth=true
Explanation:
ssh to worker1
worker1 $ vim /var/lib/kubelet/config.yaml
apiVersion: kubelet.config.k8s.io/v1beta1
authentication:
anonymous:
enabled: true #Delete this
enabled: false #Replace by this
webhook:
cacheTTL: 0s
enabled: true
x509:
clientCAFile: /etc/kubernetes/pki/ca.crt
authorization:
mode: AlwaysAllow #Delete this
mode: Webhook #Replace by this
webhook:
cacheAuthorizedTTL: 0s
cacheUnauthorizedTTL: 0s
cgroupDriver: systemd
clusterDNS:
- 10.96.0.10
clusterDomain: cluster.local
cpuManagerReconcilePeriod: 0s
evictionPressureTransitionPeriod: 0s
fileCheckFrequency: 0s
healthzBindAddress: 127.0.0.1
healthzPort: 10248
httpCheckFrequency: 0s
imageMinimumGCAge: 0s
kind: KubeletConfiguration
logging: {}
nodeStatusReportFrequency: 0s
nodeStatusUpdateFrequency: 0s
resolvConf: /run/systemd/resolve/resolv.conf
rotateCertificates: true
runtimeRequestTimeout: 0s
staticPodPath: /etc/kubernetes/manifests
streamingConnectionIdleTimeout: 0s
syncFrequency: 0s
volumeStatsAggPeriod: 0s
worker1 $ systemctl restart kubelet. # To reload kubelet config
ssh to master1
master1 $ vim /etc/kubernetes/manifests/kube-apiserver.yaml

master1 $ vim /etc/kubernetes/manifests/etcd.yaml

See the Explanation below
Explanation:

Create a PSP that will prevent the creation of privileged pods in the namespace.
$ cat clusterrole-use-privileged.yaml
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: use-privileged-psp
rules:
- apiGroups: ['policy']
resources: ['podsecuritypolicies']
verbs: ['use']
resourceNames:
- default-psp
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: privileged-role-bind
namespace: psp-test
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: use-privileged-psp
subjects:
- kind: ServiceAccount
name: privileged-sa
$ kubectl -n psp-test apply -f clusterrole-use-privileged.yaml
After a few moments, the privileged Pod should be created.
Create a new PodSecurityPolicy named prevent-privileged-policy which prevents the creation of privileged pods.
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
name: example
spec:
privileged: false # Don't allow privileged pods!
# The rest fills in some required fields.
seLinux:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
runAsUser:
rule: RunAsAny
fsGroup:
rule: RunAsAny
volumes:
- '*'
And create it with kubectl:
kubectl-admin create -f example-psp.yaml
Now, as the unprivileged user, try to create a simple pod:
kubectl-user create -f- <<EOF
apiVersion: v1
kind: Pod
metadata:
name: pause
spec:
containers:
- name: pause
image: k8s.gcr.io/pause
EOF
The output is similar to this:
Error from server (Forbidden): error when creating "STDIN": pods "pause" is forbidden: unable to validate against any pod security policy: [] Create a new ServiceAccount named psp-sa in the namespace default.
$ cat clusterrole-use-privileged.yaml
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: use-privileged-psp
rules:
- apiGroups: ['policy']
resources: ['podsecuritypolicies']
verbs: ['use']
resourceNames:
- default-psp
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: privileged-role-bind
namespace: psp-test
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: use-privileged-psp
subjects:
- kind: ServiceAccount
name: privileged-sa
$ kubectl -n psp-test apply -f clusterrole-use-privileged.yaml
After a few moments, the privileged Pod should be created.
Create a new ClusterRole named prevent-role, which uses the newly created Pod Security Policy prevent-privileged-policy.
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
name: example
spec:
privileged: false # Don't allow privileged pods!
# The rest fills in some required fields.
seLinux:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
runAsUser:
rule: RunAsAny
fsGroup:
rule: RunAsAny
volumes:
- '*'
And create it with kubectl:
kubectl-admin create -f example-psp.yaml
Now, as the unprivileged user, try to create a simple pod:
kubectl-user create -f- <<EOF
apiVersion: v1
kind: Pod
metadata:
name: pause
spec:
containers:
- name: pause
image: k8s.gcr.io/pause
EOF
The output is similar to this:
Error from server (Forbidden): error when creating "STDIN": pods "pause" is forbidden: unable to validate against any pod security policy: [] Create a new ClusterRoleBinding named prevent-role-binding, which binds the created ClusterRole prevent-role to the created SA psp-sa.
apiVersion: rbac.authorization.k8s.io/v1
# This role binding allows "jane" to read pods in the "default" namespace.
# You need to already have a Role named "pod-reader" in that namespace.
kind: RoleBinding
metadata:
name: read-pods
namespace: default
subjects:
# You can specify more than one "subject"
- kind: User
name: jane # "name" is case sensitive
apiGroup: rbac.authorization.k8s.io
roleRef:
# "roleRef" specifies the binding to a Role / ClusterRole
kind: Role #this must be Role or ClusterRole
name: pod-reader # this must match the name of the Role or ClusterRole you wish to bind to apiGroup: rbac.authorization.k8s.io apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata:
namespace: default
name: pod-reader
rules:
- apiGroups: [""] # "" indicates the core API group
resources: ["pods"]
verbs: ["get", "watch", "list"]

See the Explanation below for complete solution
Explanation:
1) Connect to the correct host
ssh cks000026
sudo -i
2) Identify the misbehaving Pod accessing /dev/mem
This task hints Falco is available → use it first (fast + intended).
2.1 Check Falco logs for /dev/mem access
journalctl -u falco | grep dev/mem
If Falco runs as a pod instead of systemd:
kubectl -n falco logs -l app=falco | grep dev/mem
2.2 Identify the Pod name
From the Falco output, you will see something like:
Pod=ollama-xxxxx Namespace=default File=/dev/mem
Note the exact Pod name (example: ollama-7c9d6f7b6d-abcde)
3) (If Falco logs are unclear) Confirm using Docker runtime
Because the cluster uses Docker, verify which container is accessing /dev/mem.
3.1 List running containers
docker ps
3.2 Inspect suspicious container
(Find container related to ollama)
docker inspect <container_id> | grep ollama
You should confirm it maps to the same Pod you saw in Falco.
4) Identify the Deployment managing the misbehaving Pod
4.1 Get Pod details
kubectl get pod <MISBEHAVING_POD_NAME> -o wide
4.2 Find owning Deployment
kubectl get pod <MISBEHAVING_POD_NAME> -o jsonpath='{.metadata.ownerReference[0].name}' This will output something like:
ollama
That is the Deployment name
5) Scale ONLY that Deployment to zero replicas
Do not edit, delete, or touch anything else
kubectl scale deployment ollama --replicas=0
6) Verify the Pod is terminated
kubectl get pods | grep ollama
Expected: no running Pods
Also confirm replicas:
kubectl get deployment ollama
Replicas should show:
0/0

A service account provides an identity for processes that run in a Pod.
When you (a human) access the cluster (for example, using kubectl), you are authenticated by the apiserver as a particular User Account (currently this is usually admin, unless your cluster administrator has customized your cluster). Processes in containers inside pods can also contact the apiserver. When they do, they are authenticated as a particular Service Account (for example, default).
When you create a pod, if you do not specify a service account, it is automatically assigned the default service account in the same namespace. If you get the raw json or yaml for a pod you have created (for example, kubectl get pods/<podname> -o yaml), you can see the spec.serviceAccountName field has been automatically set.
You can access the API from inside a pod using automatically mounted service account credentials, as described in Accessing the Cluster. The API permissions of the service account depend on the authorization plugin and policy in use.
In version 1.6+, you can opt out of automounting API credentials for a service account by setting automountServiceAccountToken: false on the service account:
apiVersion: v1
kind: ServiceAccount
metadata:
name: build-robot
automountServiceAccountToken: false
...
In version 1.6+, you can also opt out of automounting API credentials for a particular pod:
apiVersion: v1
kind: Pod
metadata:
name: my-pod
spec:
serviceAccountName: build-robot
automountServiceAccountToken: false
...
The pod spec takes precedence over the service account if both specify a automountServiceAccountToken value.