Configuring a Pod Security Policy¶
A pod security policy (PSP) is a cluster-level resource that controls sensitive security aspects of the pod specification. The PodSecurityPolicy object in Kubernetes defines a group of conditions that a pod must comply with to be accepted by the system, as well as the default values of related fields.
By default, the PSP access control component is enabled for clusters of v1.17.17 and a global default PSP named psp-global is created. You can modify the default policy (but not delete it). You can also create a PSP and bind it to the RBAC configuration.
Note
In addition to the global default PSP, the system configures independent PSPs for system components in namespace kube-system. Modifying the psp-global configuration does not affect pod creation in namespace kube-system.
In Kubernetes 1.25, PSP has been removed and replaced by Pod Security Admission. For details, see Configuring Pod Security Admission.
Modifying the Global Default PSP¶
Before modifying the global default PSP, ensure that a CCE cluster has been created and connected by using kubectl.
Run the following command:
kubectl edit psp psp-global
Modify the parameters as required. For details, see PodSecurityPolicy.
Example of Enabling Unsafe Sysctls in Pod Security Policy¶
You can configure allowed-unsafe-sysctls for a node pool. For CCE v1.17.17 and later versions, add configurations in allowedUnsafeSysctls of the pod security policy to make the configuration take effect. For details, see PodSecurityPolicy.
In addition to modifying the global pod security policy, you can add new pod security policies. For example, enable the net.core.somaxconn unsafe sysctls. The following is an example of adding a pod security policy:
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
annotations:
seccomp.security.alpha.kubernetes.io/allowedProfileNames: '*'
name: sysctl-psp
spec:
allowedUnsafeSysctls:
- net.core.somaxconn
allowPrivilegeEscalation: true
allowedCapabilities:
- '*'
fsGroup:
rule: RunAsAny
hostIPC: true
hostNetwork: true
hostPID: true
hostPorts:
- max: 65535
min: 0
privileged: true
runAsGroup:
rule: RunAsAny
runAsUser:
rule: RunAsAny
seLinux:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
volumes:
- '*'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: sysctl-psp
rules:
- apiGroups:
- "*"
resources:
- podsecuritypolicies
resourceNames:
- sysctl-psp
verbs:
- use
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: sysctl-psp
roleRef:
kind: ClusterRole
name: sysctl-psp
apiGroup: rbac.authorization.k8s.io
subjects:
- kind: Group
name: system:authenticated
apiGroup: rbac.authorization.k8s.io
Restoring the Original PSP¶
If you have modified the default pod security policy and want to restore the original pod security policy, perform the following operations.
Create a policy description file named policy.yaml. policy.yaml is an example file name. You can rename it as required.
vi policy.yaml
The content of the description file is as follows:
apiVersion: policy/v1beta1 kind: PodSecurityPolicy metadata: name: psp-global annotations: seccomp.security.alpha.kubernetes.io/allowedProfileNames: '*' spec: privileged: true allowPrivilegeEscalation: true allowedCapabilities: - '*' volumes: - '*' hostNetwork: true hostPorts: - min: 0 max: 65535 hostIPC: true hostPID: true runAsUser: rule: 'RunAsAny' seLinux: rule: 'RunAsAny' supplementalGroups: rule: 'RunAsAny' fsGroup: rule: 'RunAsAny' --- kind: ClusterRole apiVersion: rbac.authorization.k8s.io/v1 metadata: name: psp-global rules: - apiGroups: - "*" resources: - podsecuritypolicies resourceNames: - psp-global verbs: - use --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: psp-global roleRef: kind: ClusterRole name: psp-global apiGroup: rbac.authorization.k8s.io subjects: - kind: Group name: system:authenticated apiGroup: rbac.authorization.k8s.io
Run the following command:
kubectl apply -f policy.yaml