Linux Foundation CKS 問題集

質問 1：
You can switch the cluster/configuration context using the following command: [desk@cli] $ kubectl config use-context test-account Task: Enable audit logs in the cluster.
To do so, enable the log backend, and ensure that:
1. logs are stored at /var/log/Kubernetes/logs.txt
2. log files are retained for 5 days
3. at maximum, a number of 10 old audit log files are retained
A basic policy is provided at /etc/Kubernetes/logpolicy/audit-policy.yaml. It only specifies what not to log. Note: The base policy is located on the cluster's master node.
Edit and extend the basic policy to log: 1. Nodes changes at RequestResponse level 2. The request body of persistentvolumes changes in the namespace frontend 3. ConfigMap and Secret changes in all namespaces at the Metadata level Also, add a catch-all rule to log all other requests at the Metadata level Note: Don't forget to apply the modified policy.
正解：
$ vim /etc/kubernetes/log-policy/audit-policy.yaml
- level: RequestResponse
userGroups: ["system:nodes"]
- level: Request
resources:
- group: "" # core API group
resources: ["persistentvolumes"]
namespaces: ["frontend"]
- level: Metadata
resources:
- group: ""
resources: ["configmaps", "secrets"]
- level: Metadata
$ vim /etc/kubernetes/manifests/kube-apiserver.yaml Add these
- --audit-policy-file=/etc/kubernetes/log-policy/audit-policy.yaml
- --audit-log-path=/var/log/kubernetes/logs.txt
- --audit-log-maxage=5
- --audit-log-maxbackup=10
Explanation
[desk@cli] $ ssh master1 [master1@cli] $ vim /etc/kubernetes/log-policy/audit-policy.yaml apiVersion: audit.k8s.io/v1 # This is required.
kind: Policy
# Don't generate audit events for all requests in RequestReceived stage.
omitStages:
- "RequestReceived"
rules:
# Don't log watch requests by the "system:kube-proxy" on endpoints or services
- level: None
users: ["system:kube-proxy"]
verbs: ["watch"]
resources:
- group: "" # core API group
resources: ["endpoints", "services"]
# Don't log authenticated requests to certain non-resource URL paths.
- level: None
userGroups: ["system:authenticated"]
nonResourceURLs:
- "/api*" # Wildcard matching.
- "/version"
# Add your changes below
- level: RequestResponse
userGroups: ["system:nodes"] # Block for nodes
- level: Request
resources:
- group: "" # core API group
resources: ["persistentvolumes"] # Block for persistentvolumes
namespaces: ["frontend"] # Block for persistentvolumes of frontend ns
- level: Metadata
resources:
- group: "" # core API group
resources: ["configmaps", "secrets"] # Block for configmaps & secrets
- level: Metadata # Block for everything else
[master1@cli] $ vim /etc/kubernetes/manifests/kube-apiserver.yaml
apiVersion: v1
kind: Pod
metadata:
annotations:
kubeadm.kubernetes.io/kube-apiserver.advertise-address.endpoint: 10.0.0.5:6443 labels:
component: kube-apiserver
tier: control-plane
name: kube-apiserver
namespace: kube-system
spec:
containers:
- command:
- kube-apiserver
- --advertise-address=10.0.0.5
- --allow-privileged=true
- --authorization-mode=Node,RBAC
- --audit-policy-file=/etc/kubernetes/log-policy/audit-policy.yaml #Add this
- --audit-log-path=/var/log/kubernetes/logs.txt #Add this
- --audit-log-maxage=5 #Add this
- --audit-log-maxbackup=10 #Add this
...
output truncated
Note: log volume & policy volume is already mounted in vim /etc/kubernetes/manifests/kube-apiserver.yaml so no need to mount it. Reference: https://kubernetes.io/docs/tasks/debug-application-cluster/audit/

質問 2：
You can switch the cluster/configuration context using the following command: [desk@cli] $ kubectl config use-context qa Context: A pod fails to run because of an incorrectly specified ServiceAccount Task: Create a new service account named backend-qa in an existing namespace qa, which must not have access to any secret. Edit the frontend pod yaml to use backend-qa service account Note: You can find the frontend pod yaml at /home/cert_masters/frontend-pod.yaml
正解：
[desk@cli] $ k create sa backend-qa -n qa sa/backend-qa created [desk@cli] $ k get role,rolebinding -n qa No resources found in qa namespace. [desk@cli] $ k create role backend -n qa --resource pods,namespaces,configmaps --verb list # No access to secret [desk@cli] $ k create rolebinding backend -n qa --role backend --serviceaccount qa:backend-qa [desk@cli] $ vim /home/cert_masters/frontend-pod.yaml apiVersion: v1 kind: Pod metadata:
name: frontend
spec:
serviceAccountName: backend-qa # Add this
image: nginx
name: frontend
[desk@cli] $ k apply -f /home/cert_masters/frontend-pod.yaml pod created
[desk@cli] $ k create sa backend-qa -n qa serviceaccount/backend-qa created [desk@cli] $ k get role,rolebinding -n qa No resources found in qa namespace. [desk@cli] $ k create role backend -n qa --resource pods,namespaces,configmaps --verb list role.rbac.authorization.k8s.io/backend created [desk@cli] $ k create rolebinding backend -n qa --role backend --serviceaccount qa:backend-qa rolebinding.rbac.authorization.k8s.io/backend created [desk@cli] $ vim /home/cert_masters/frontend-pod.yaml apiVersion: v1 kind: Pod metadata:
name: frontend
spec:
serviceAccountName: backend-qa # Add this
image: nginx
name: frontend
[desk@cli] $ k apply -f /home/cert_masters/frontend-pod.yaml pod/frontend created https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/

質問 3：
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 4：
Secrets stored in the etcd is not secure at rest, you can use the etcdctl command utility to find the secret value for e.g:- ETCDCTL_API=3 etcdctl get /registry/secrets/default/cks-secret --cacert="ca.crt" --cert="server.crt" --key="server.key" Output

Using the Encryption Configuration, Create the manifest, which secures the resource secrets using the provider AES-CBC and identity, to encrypt the secret-data at rest and ensure all secrets are encrypted with the new configuration.
正解：
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

質問 5：
Context: Cluster: gvisor Master node: master1 Worker node: worker1
You can switch the cluster/configuration context using the following command:
[desk@cli] $ kubectl config use-context gvisor
Context: This cluster has been prepared to support runtime handler, runsc as well as traditional one.
Task: Create a RuntimeClass named not-trusted using the prepared runtime handler names runsc. Update all Pods in the namespace server to run on newruntime.
正解：

Explanation
[desk@cli] $vim runtime.yaml
apiVersion: node.k8s.io/v1
kind: RuntimeClass
metadata:
name: not-trusted
handler: runsc
[desk@cli] $ k apply -f runtime.yaml [desk@cli] $ k get pods
NAME READY STATUS RESTARTS AGE
nginx-6798fc88e8-chp6r 1/1 Running 0 11m
nginx-6798fc88e8-fs53n 1/1 Running 0 11m
nginx-6798fc88e8-ndved 1/1 Running 0 11m
[desk@cli] $ k get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 3/3 11 3 5m
[desk@cli] $ k edit deploy nginx