CKS 無料問題集「Linux Foundation Certified Kubernetes Security Specialist (CKS)」
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 12 days.
3. at maximum, a number of 8 old audit logs files are retained.
4. set the maximum size before getting rotated to 200MB
Edit and extend the basic policy to log:
1. namespaces changes at RequestResponse
2. Log the request body of secrets changes in the namespace kube-system.
3. Log all other resources in core and extensions at the Request level.
4. Log "pods/portforward", "services/proxy" at Metadata level.
5. Omit the Stage RequestReceived
All other requests at the Metadata level
1. logs are stored at /var/log/kubernetes-logs.txt.
2. Log files are retained for 12 days.
3. at maximum, a number of 8 old audit logs files are retained.
4. set the maximum size before getting rotated to 200MB
Edit and extend the basic policy to log:
1. namespaces changes at RequestResponse
2. Log the request body of secrets changes in the namespace kube-system.
3. Log all other resources in core and extensions at the Request level.
4. Log "pods/portforward", "services/proxy" at Metadata level.
5. Omit the Stage RequestReceived
All other requests at the Metadata level
正解：
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
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
Two tools are pre-installed on the cluster's worker node:
Using the tool of your choice (including any non pre-installed tool), analyze the container's behavior for at least 30 seconds, using filters that detect newly spawning and executing processes.
Store an incident file at /opt/KSRS00101/alerts/details, containing the detected incidents, one per line, in the following format:
The following example shows a properly formatted incident file:
Using the tool of your choice (including any non pre-installed tool), analyze the container's behavior for at least 30 seconds, using filters that detect newly spawning and executing processes.
Store an incident file at /opt/KSRS00101/alerts/details, containing the detected incidents, one per line, in the following format:
The following example shows a properly formatted incident file:
正解：
You can switch the cluster/configuration context using the following command: [desk@cli] $ kubectl config use-context dev A default-deny NetworkPolicy avoid to accidentally expose a Pod in a namespace that doesn't have any other NetworkPolicy defined.
Task: Create a new default-deny NetworkPolicy named deny-network in the namespace test for all traffic of type Ingress + Egress The new NetworkPolicy must deny all Ingress + Egress traffic in the namespace test.
Apply the newly created default-deny NetworkPolicy to all Pods running in namespace test.
You can find a skeleton manifests file at /home/cert_masters/network-policy.yaml
Task: Create a new default-deny NetworkPolicy named deny-network in the namespace test for all traffic of type Ingress + Egress The new NetworkPolicy must deny all Ingress + Egress traffic in the namespace test.
Apply the newly created default-deny NetworkPolicy to all Pods running in namespace test.
You can find a skeleton manifests file at /home/cert_masters/network-policy.yaml
正解：
master1 $ k get pods -n test --show-labels
NAME READY STATUS RESTARTS AGE LABELS
test-pod 1/1 Running 0 34s role=test,run=test-pod
testing 1/1 Running 0 17d run=testing
$ vim netpol.yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: deny-network
namespace: test
spec:
podSelector: {}
policyTypes:
- Ingress
- Egress
master1 $ k apply -f netpol.yaml
Explanation
controlplane $ k get pods -n test --show-labels
NAME READY STATUS RESTARTS AGE LABELS
test-pod 1/1 Running 0 34s role=test,run=test-pod
testing 1/1 Running 0 17d run=testing
master1 $ vim netpol1.yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: deny-network
namespace: test
spec:
podSelector: {}
policyTypes:
- Ingress
- Egress
master1 $ k apply -f netpol1.yaml Reference: https://kubernetes.io/docs/concepts/services-networking/network-policies/ Explanation controlplane $ k get pods -n test --show-labels NAME READY STATUS RESTARTS AGE LABELS test-pod 1/1 Running 0 34s role=test,run=test-pod testing 1/1 Running 0 17d run=testing master1 $ vim netpol1.yaml apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata:
name: deny-network
namespace: test
spec:
podSelector: {}
policyTypes:
- Ingress
- Egress
master1 $ k apply -f netpol1.yaml Reference: https://kubernetes.io/docs/concepts/services-networking/network-policies/
NAME READY STATUS RESTARTS AGE LABELS
test-pod 1/1 Running 0 34s role=test,run=test-pod
testing 1/1 Running 0 17d run=testing
$ vim netpol.yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: deny-network
namespace: test
spec:
podSelector: {}
policyTypes:
- Ingress
- Egress
master1 $ k apply -f netpol.yaml
Explanation
controlplane $ k get pods -n test --show-labels
NAME READY STATUS RESTARTS AGE LABELS
test-pod 1/1 Running 0 34s role=test,run=test-pod
testing 1/1 Running 0 17d run=testing
master1 $ vim netpol1.yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: deny-network
namespace: test
spec:
podSelector: {}
policyTypes:
- Ingress
- Egress
master1 $ k apply -f netpol1.yaml Reference: https://kubernetes.io/docs/concepts/services-networking/network-policies/ Explanation controlplane $ k get pods -n test --show-labels NAME READY STATUS RESTARTS AGE LABELS test-pod 1/1 Running 0 34s role=test,run=test-pod testing 1/1 Running 0 17d run=testing master1 $ vim netpol1.yaml apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata:
name: deny-network
namespace: test
spec:
podSelector: {}
policyTypes:
- Ingress
- Egress
master1 $ k apply -f netpol1.yaml Reference: https://kubernetes.io/docs/concepts/services-networking/network-policies/
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/
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/
You must complete this task on the following cluster/nodes: Cluster: immutable-cluster Master node: master1 Worker node: worker1 You can switch the cluster/configuration context using the following command: [desk@cli] $ kubectl config use-context immutable-cluster Context: It is best practice to design containers to be stateless and immutable. Task: Inspect Pods running in namespace prod and delete any Pod that is either not stateless or not immutable. Use the following strict interpretation of stateless and immutable: 1. Pods being able to store data inside containers must be treated as not stateless. Note: You don't have to worry whether data is actually stored inside containers or not already. 2. Pods being configured to be privileged in any way must be treated as potentially not stateless or not immutable.
正解：
Reference: https://kubernetes.io/docs/concepts/policy/pod-security-policy/ https://cloud.google.com/architecture/best-practices-for-operating-containers