Note
本教程仅适用于新集群。
Pod 安全准入（PSA）在 v1.23 及更高版本默认启用， 因为它升级到测试版（beta）。 Pod 安全准入是在创建 Pod 时应用 Pod 安全标准的准入控制器。 本教程将向你展示如何在集群级别实施 baseline Pod 安全标准， 该标准将标准配置应用于集群中的所有名称空间。
在你的工作站中安装以下内容：
KinD kubectlPod 安全准入 允许你使用以下模式应用内置的 Pod 安全标准: enforce、audit 和 warn。
要收集信息以便选择最适合你的配置的 Pod 安全标准，请执行以下操作：
kind create cluster --name psa-wo-cluster-pss --image kindest/node:v1.23.0
输出类似于：
Creating cluster "psa-wo-cluster-pss" ...将 kubectl 上下文设置为新集群：
✓ Ensuring node image (kindest/node:v1.23.0)
✓ Preparing nodes
✓ Writing configuration
✓ Starting control-plane ️
✓ Installing CNI
✓ Installing StorageClass
Set kubectl context to "kind-psa-wo-cluster-pss"
You can now use your cluster with:
kubectl cluster-info --context kind-psa-wo-cluster-pss
Thanks for using kind!
kubectl cluster-info --context kind-psa-wo-cluster-pss
输出类似于：
Kubernetes control plane is running at https://127.0.0.1:61350获取集群中的名字空间列表：
CoreDNS is running at https://127.0.0.1:61350/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
kubectl get ns
输出类似于：
NAME STATUS AGE使用
default Active 9m30s
kube-node-lease Active 9m32s
kube-public Active 9m32s
kube-system Active 9m32s
local-path-storage Active 9m26s
--dry-run=server 来了解应用不同的 Pod 安全标准时会发生什么： kubectl label --dry-run=server --overwrite ns --all \
pod-security.kubernetes.io/enforce=privileged
输出类似于：
namespace/default labeled
namespace/kube-node-lease labeled
namespace/kube-public labeled
namespace/kube-system labeled
namespace/local-path-storage labeled
kubectl label --dry-run=server --overwrite ns --all \
pod-security.kubernetes.io/enforce=baseline
输出类似于：
namespace/default labeled
namespace/kube-node-lease labeled
namespace/kube-public labeled
Warning: existing pods in namespace "kube-system" violate the new PodSecurity enforce level "baseline:latest"
Warning: etcd-psa-wo-cluster-pss-control-plane (and 3 other pods): host namespaces, hostPath volumes
Warning: kindnet-vzj42: non-default capabilities, host namespaces, hostPath volumes
Warning: kube-proxy-m6hwf: host namespaces, hostPath volumes, privileged
namespace/kube-system labeled
namespace/local-path-storage labeled
kubectl label --dry-run=server --overwrite ns --all \
pod-security.kubernetes.io/enforce=restricted
输出类似于：
namespace/default labeled
namespace/kube-node-lease labeled
namespace/kube-public labeled
Warning: existing pods in namespace "kube-system" violate the new PodSecurity enforce level "restricted:latest"
Warning: coredns-7bb9c7b568-hsptc (and 1 other pod): unrestricted capabilities, runAsNonRoot != true, seccompProfile
Warning: etcd-psa-wo-cluster-pss-control-plane (and 3 other pods): host namespaces, hostPath volumes, allowPrivilegeEscalation != false, unrestricted capabilities, restricted volume types, runAsNonRoot != true
Warning: kindnet-vzj42: non-default capabilities, host namespaces, hostPath volumes, allowPrivilegeEscalation != false, unrestricted capabilities, restricted volume types, runAsNonRoot != true, seccompProfile
Warning: kube-proxy-m6hwf: host namespaces, hostPath volumes, privileged, allowPrivilegeEscalation != false, unrestricted capabilities, restricted volume types, runAsNonRoot != true, seccompProfile
namespace/kube-system labeled
Warning: existing pods in namespace "local-path-storage" violate the new PodSecurity enforce level "restricted:latest"
Warning: local-path-provisioner-d6d9f7ffc-lw9lh: allowPrivilegeEscalation != false, unrestricted capabilities, runAsNonRoot != true, seccompProfile
namespace/local-path-storage labeled
从前面的输出中，你会注意到应用 privileged Pod 安全标准不会显示任何名字空间的警告。 然而，baseline 和 restricted 标准都有警告，特别是在 kube-system 名字空间中。
在本节中，你将以下 Pod 安全标准应用于最新（latest）版本：
enforce 模式下的 baseline 标准。warn 和 audit 模式下的 restricted 标准。baseline Pod 安全标准提供了一个方便的中间立场，能够保持豁免列表简短并防止已知的特权升级。
此外，为了防止 kube-system 中的 Pod 失败，你将免除该名字空间应用 Pod 安全标准。
在你自己的环境中实施 Pod 安全准入时，请考虑以下事项：
restricted）可能是更好的选择。kube-system 名字空间进行赦免会允许 Pod 在其中以 privileged 模式运行。 对于实际使用，Kubernetes 项目强烈建议你应用严格的 RBAC 策略来限制对 kube-system 的访问， 遵循最小特权原则。mkdir -p /tmp/pss在创建集群时配置 API 服务器使用此文件：
cat <<EOF > /tmp/pss/cluster-level-pss.yaml
apiVersion: apiserver.config.k8s.io/v1
kind: AdmissionConfiguration
plugins:
- name: PodSecurity
configuration:
apiVersion: pod-security.admission.config.k8s.io/v1beta1
kind: PodSecurityConfiguration
defaults:
enforce: "baseline"
enforce-version: "latest"
audit: "restricted"
audit-version: "latest"
warn: "restricted"
warn-version: "latest"
exemptions:
usernames: []
runtimeClasses: []
namespaces: [kube-system]
EOF
cat <<EOF > /tmp/pss/cluster-config.yaml
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
kubeadmConfigPatches:
- |
kind: ClusterConfiguration
apiServer:
extraArgs:
admission-control-config-file: /etc/config/cluster-level-pss.yaml
extraVolumes:
- name: accf
hostPath: /etc/config
mountPath: /etc/config
readOnly: false
pathType: "DirectoryOrCreate"
extraMounts:
- hostPath: /tmp/pss
containerPath: /etc/config
# optional: if set, the mount is read-only.
# default false
readOnly: false
# optional: if set, the mount needs SELinux relabeling.
# default false
selinuxRelabel: false
# optional: set propagation mode (None, HostToContainer or Bidirectional)
# see https://kubernetes.io/docs/concepts/storage/volumes/#mount-propagation
# default None
propagation: None
EOF
说明：
如果你在 macOS 上使用 Docker Desktop 和 KinD， 你可以在菜单项 Preferences > Resources > File Sharing 下添加 /tmp 作为共享目录。 创建一个使用 Pod 安全准入的集群来应用这些 Pod 安全标准：
kind create cluster --name psa-with-cluster-pss --image kindest/node:v1.23.0 --config /tmp/pss/cluster-config.yaml
输出类似于：
Creating cluster "psa-with-cluster-pss" ...将 kubectl 指向集群
✓ Ensuring node image (kindest/node:v1.23.0)
✓ Preparing nodes
✓ Writing configuration
✓ Starting control-plane ️
✓ Installing CNI
✓ Installing StorageClass
Set kubectl context to "kind-psa-with-cluster-pss"
You can now use your cluster with:
kubectl cluster-info --context kind-psa-with-cluster-pss
Have a question, bug, or feature request? Let us know! https://kind.sigs.k8s.io/#community
kubectl cluster-info --context kind-psa-with-cluster-pss
输出类似于：
Kubernetes control plane is running at https://127.0.0.1:63855创建以下 Pod 规约作为在 default 名字空间中的一个最小配置：
CoreDNS is running at https://127.0.0.1:63855/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
cat <<EOF > /tmp/pss/nginx-pod.yaml在集群中创建 Pod：
apiVersion: v1
kind: Pod
metadata:
name: nginx
spec:
containers:
- image: nginx
name: nginx
ports:
- containerPort: 80
EOF
kubectl apply -f /tmp/pss/nginx-pod.yaml
输出类似于：
Warning: would violate PodSecurity "restricted:latest": allowPrivilegeEscalation != false (container "nginx" must set securityContext allowPrivilegeEscalation=false), unrestricted capabilities (container "nginx" must set securityContext.capabilities.drop=["ALL"]), runAsNonRoot != true (pod or container "nginx" must set securityContext.runAsNonRoot=true), seccompProfile (pod or container "nginx" must set securityContext seccompProfile.type to "RuntimeDefault" or "Localhost")
pod/nginx created
运行 kind delete cluster --name psa-with-cluster-pss 和 kind delete cluster --name psa-wo-cluster-pss 来删除你创建的集群。