CKS Dumps Questions With Valid Answers

Explanation:
API server:
Ensure the --authorization-mode argument includes RBAC
Turn on Role Based Access Control.Role Based Access Control (RBAC) allows finegrained control over the operations that different entities can perform on different objects in the cluster. It is recommended to use the RBAC authorization mode.
Fix - BuildtimeKubernetesapiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
component: kube-apiserver
tier: control-plane
name: kube-apiserver
namespace: kube-system
spec:
containers:
- command:
+ - kube-apiserver
+ - --authorization-mode=RBAC,Node
image: gcr.io/google_containers/kube-apiserver-amd64:v1.6.0
livenessProbe:
failureThreshold: 8
httpGet:
host: 127.0.0.1
path: /healthz
port: 6443
scheme: HTTPS
initialDelaySeconds: 15
timeoutSeconds: 15
name: kube-apiserver-should-pass
resources:
requests:
cpu: 250m
volumeMounts:
- mountPath: /etc/kubernetes/
name: k8s
readOnly: true
- mountPath: /etc/ssl/certs
name: certs
- mountPath: /etc/pki
name: pki
hostNetwork: true
volumes:
- hostPath:
path: /etc/kubernetes
name: k8s
- hostPath:
path: /etc/ssl/certs
name: certs
- hostPath:
path: /etc/pki
name: pki
Ensure the --authorization-mode argument includes Node
Remediation: Edit the API server pod specification file /etc/kubernetes/manifests/kubeapiserver.
yaml on the master node and set the --authorization-mode parameter to a value that includes Node.
--authorization-mode=Node,RBAC
Audit:
/bin/ps -ef | grep kube-apiserver | grep -v grep
Expected result:
'Node,RBAC' has 'Node'
Ensure that the --profiling argument is set to false
Remediation: Edit the API server pod specification file /etc/kubernetes/manifests/kubeapiserver.
yaml on the master node and set the below parameter.
--profiling=false
Audit:
/bin/ps -ef | grep kube-apiserver | grep -v grep
Expected result:
'false' is equal to 'false'
Fix all of the following violations that were found against the Kubelet:-
uk.co.certification.simulator.questionpool.PList@e3e35a0
Remediation: If using a Kubelet config file, edit the file to set authentication: anonymous:
enabled to false. If using executable arguments, edit the kubelet service file /etc/systemd/system/kubelet.service.d/10-kubeadm.conf on each worker node and set the below parameter in KUBELET_SYSTEM_PODS_ARGS variable.
--anonymous-auth=false
Based on your system, restart the kubelet service. For example:
systemctl daemon-reload
systemctl restart kubelet.service
Audit:
/bin/ps -fC kubelet
Audit Config:
/bin/cat /var/lib/kubelet/config.yaml
Expected result:
'false' is equal to 'false'
2) Ensure that the --authorization-mode argument is set to Webhook.
Audit
docker inspect kubelet | jq -e '.[0].Args[] | match("--authorizationmode= Webhook").string'
Returned Value: --authorization-mode=Webhook
Fix all of the following violations that were found against the ETCD:-
a. Ensure that the --auto-tls argument is not set to true
Do not use self-signed certificates for TLS. etcd is a highly-available key value store used by Kubernetes deployments for persistent storage of all of its REST API objects. These objects are sensitive in nature and should not be available to unauthenticated clients. You should enable the client authentication via valid certificates to secure the access to the etcd service.
Fix - BuildtimeKubernetesapiVersion: v1
kind: Pod
metadata:
annotations:
scheduler.alpha.kubernetes.io/critical-pod: ""
creationTimestamp: null
labels:
component: etcd
tier: control-plane
name: etcd
namespace: kube-system
spec:
containers:
- command:
+ - etcd
+ - --auto-tls=true
image: k8s.gcr.io/etcd-amd64:3.2.18
imagePullPolicy: IfNotPresent
livenessProbe:
exec:
command:
- /bin/sh
- -ec
- ETCDCTL_API=3 etcdctl --endpoints=https://[192.168.22.9]:2379 --
cacert=/etc/kubernetes/pki/etcd/ca.crt
--cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt --
key=/etc/kubernetes/pki/etcd/healthcheck-client.key
get foo
failureThreshold: 8
initialDelaySeconds: 15
timeoutSeconds: 15
name: etcd-should-fail
resources: {}
volumeMounts:
- mountPath: /var/lib/etcd
name: etcd-data
- mountPath: /etc/kubernetes/pki/etcd
name: etcd-certs
hostNetwork: true
priorityClassName: system-cluster-critical
volumes:
- hostPath:
path: /var/lib/etcd
type: DirectoryOrCreate
name: etcd-data
- hostPath:
path: /etc/kubernetes/pki/etcd
type: DirectoryOrCreate
name: etcd-certs
status: {}

Explanation:
1. For Dockerfile: Fix the image version & user name in Dockerfile2. 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"]

Explanation:
Kubernetes auditing provides a security-relevant chronological set of records about a cluster. Kube-apiserver performs auditing. Each request on each stage of its execution generates an event, which is then pre-processed according to a certain policy and written to a backend. The policy determines what’s recorded and the backends persist the records.
You might want to configure the audit log as part of compliance with the CIS (Center for Internet Security) Kubernetes Benchmark controls.
The audit log can be enabled by default using the following configuration in cluster.yml:
services:
kube-api:
audit_log:
enabled: true
When the audit log is enabled, you should be able to see the default values at /etc/kubernetes/audit-policy.yaml
The log backend writes audit events to a file in JSONlines format. You can configure the log audit backend using the following kube-apiserver flags:
--audit-log-path specifies the log file path that log backend uses to write audit events. Not specifying this flag disables log backend. - means standard out
--audit-log-maxage defined the maximum number of days to retain old audit log files
--audit-log-maxbackup defines the maximum number of audit log files to retain
--audit-log-maxsize defines the maximum size in megabytes of the audit log file before it gets rotated
If your cluster's control plane runs the kube-apiserver as a Pod, remember to mount the hostPath to the location of the policy file and log file, so that audit records are persisted.
For example:
--audit-policy-file=/etc/kubernetes/audit-policy.yaml \
--audit-log-path=/var/log/audit.log