使用集合让一切井井有条 根据您的偏好保存内容并对其进行分类。

使用 CIS Kubernetes 基准政策限制条件

政策控制器附带默认的限制条件模板库,您可以将该库与 CIS 软件包搭配使用,从而根据CIS Kubernetes 基准来审核集群的合规性。此基准是一系列关于配置 Kubernetes 以支持可靠的安全状况的建议。

此限制条件软件包在以下网域中处理并强制执行政策:

  • RBAC 和服务帐号
  • Pod 安全政策
  • 网络政策和 CNI
  • 密文管理
  • 常规政策

这些政策尚未通过 CIS 认证。

该软件包包含以下限制条件,以满足 CIS 基准中相应控制措施的要求:

限制条件 对照组 ID 对照组说明 参照
psp-privileged-container 5.2.1 尽可能减少特权容器的准许
psp-host-namespace 5.2.2 尽可能减少希望共享主机进程 ID 命名空间的容器的准许
5.2.3 尽可能减少希望共享主机 IPC 命名空间的容器的准许
psp-host-network-ports 5.2.4 尽可能减少希望共享主机网络命名空间的容器的准许
psp-allow-privilege-escalation-container 5.2.5 尽可能减少具有 allowPrivilegeEscalation 的容器的准许
psp-pods-must-run-as-nonroot 5.2.6 尽可能减少根容器的准许
psp-capabilities 5.2.7 尽可能减少具有 NET_RAW 功能的容器的准许
5.2.8 尽可能减少具有附加功能的容器的准许
5.2.9 尽可能减少具有分配的功能的容器的准许
require-namespace-network-policies 5.3.2 确保所有命名空间都定义了网络政策
no-secrets-as-env-vars 5.4.1 优先将 Secret 用作文件而不是用作环境变量
psp-seccomp-default 5.7.2 确保在 pod 定义中将 seccomp 配置文件设置为 docker/default
pods-require-security-context 5.7.3 将安全上下文应用到您的 Pod 和容器

准备工作

  1. 安装并初始化 Google Cloud CLI,它提供了以下说明中使用的 gcloudkubectl 命令。如果您使用 Cloud Shell,则系统会预安装 Google Cloud CLI。
  2. 在集群上安装政策控制器以及默认的限制条件模板库。您还必须启用对参照限制条件的支持,因为此捆绑包包含一览表中列出的参照限制条件。

为参照限制条件配置政策控制器

  1. 在文件中,将以下 YAML 清单保存为 policycontroller-config.yaml。清单将政策控制器配置为监视特定种类的对象。

    apiVersion: config.gatekeeper.sh/v1alpha1
    kind: Config
    metadata:
      name: config
      namespace: "gatekeeper-system"
    spec:
      sync:
        syncOnly:
          - group: ""
            version: "v1"
            kind: "Namespace"
          - group: "networking.k8s.io"
            version: "v1"
            kind: "NetworkPolicy"
    
  2. 应用 policycontroller-config.yaml 清单:

    kubectl apply -f policycontroller-config.yaml
    

使用政策控制器审核 CIS 政策

政策控制器允许您为 Kubernetes 集群强制执行政策。为了帮助测试您的工作负载及其对上表中列出的 CIS 政策的合规性,您可以在“审核”模式下部署这些限制条件以发现违规行为,更重要的是让您有机会在 Kubernetes 集群上强制执行之前处理这些违规行为。

您可以在 spec.enforcementAction 设置为 dryrun 的情况下,使用 kubectl、kptConfig Sync 应用这些政策。

kubectl

  1. (可选)使用 kubectl 预览政策限制条件:

    kubectl kustomize https://github.com/GoogleCloudPlatform/acm-policy-controller-library.git/bundles/cis-k8s-v1.5.1
    
  2. 使用 kubectl 应用政策限制条件:

    kubectl apply -k https://github.com/GoogleCloudPlatform/acm-policy-controller-library.git/bundles/cis-k8s-v1.5.1
    

    输出如下所示:

    k8snoenvvarsecrets.constraints.gatekeeper.sh/cis-k8s-v1.5.1-no-secrets-as-env-vars created
    k8spspallowprivilegeescalationcontainer.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-allow-privilege-escalation created
    k8spspallowedusers.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-pods-must-run-as-nonroot created
    k8spspcapabilities.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-capabilities created
    k8spsphostnamespace.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-host-namespace created
    k8spsphostnetworkingports.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-host-network-ports created
    k8spspprivilegedcontainer.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-privileged-container created
    k8spspseccomp.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-seccomp-default created
    k8spodsrequiresecuritycontext.constraints.gatekeeper.sh/cis-k8s-v1.5.1-pods-require-security-context created
    k8sprohibitrolewildcardaccess.constraints.gatekeeper.sh/cis-k8s-v1.5.1-prohibit-role-wildcard-access created
    k8srequirenamespacenetworkpolicies.constraints.gatekeeper.sh/cis-k8s-v1.5.1-require-namespace-network-policies created
    k8srestrictrolebindings.constraints.gatekeeper.sh/cis-k8s-v1.5.1-restrict-clusteradmin-rolebindings created
    
  3. 验证政策限制条件是否已安装,并检查集群中是否存在违规行为:

    kubectl get -k https://github.com/GoogleCloudPlatform/acm-policy-controller-library.git/bundles/cis-k8s-v1.5.1
    

    输出类似于以下内容:

    NAME                                                                                 ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8snoenvvarsecrets.constraints.gatekeeper.sh/cis-k8s-v1.5.1-no-secrets-as-env-vars   dryrun               0
    
    NAME                                                                                                              ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8spspallowprivilegeescalationcontainer.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-allow-privilege-escalation   dryrun               0
    
    NAME                                                                                       ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8spspallowedusers.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-pods-must-run-as-nonroot   dryrun               0
    
    NAME                                                                           ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8spspcapabilities.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-capabilities   dryrun               0
    
    NAME                                                                              ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8spsphostnamespace.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-host-namespace   dryrun               0
    
    NAME                                                                                        ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8spsphostnetworkingports.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-host-network-ports   dryrun               0
    
    NAME                                                                                          ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8spspprivilegedcontainer.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-privileged-container   dryrun               0
    
    NAME                                                                         ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8spspseccomp.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-seccomp-default   dryrun               0
    
    NAME                                                                                                   ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8spodsrequiresecuritycontext.constraints.gatekeeper.sh/cis-k8s-v1.5.1-pods-require-security-context   dryrun               0
    
    NAME                                                                                                   ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8sprohibitrolewildcardaccess.constraints.gatekeeper.sh/cis-k8s-v1.5.1-prohibit-role-wildcard-access   dryrun               0
    
    NAME                                                                                                             ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8srequirenamespacenetworkpolicies.constraints.gatekeeper.sh/cis-k8s-v1.5.1-require-namespace-network-policies   dryrun               0
    
    NAME                                                                                                  ENFORCEMENT-ACTION   TOTAL-VIOLATIONS
    k8srestrictrolebindings.constraints.gatekeeper.sh/cis-k8s-v1.5.1-restrict-clusteradmin-rolebindings   dryrun               0
    

kpt

  1. 安装并设置 kpt。在这些说明中,kpt 用于自定义和部署 Kubernetes 资源。

  2. 使用 kpt 从 GitHub 下载 CIS 政策软件包:

    kpt pkg get https://github.com/GoogleCloudPlatform/acm-policy-controller-library.git/bundles/cis-k8s-v1.5.1
    
  3. 运行 set-enforcement-action kpt 函数将政策的强制执行操作设置为 dryrun

    kpt fn eval cis-k8s-v1.5.1 -i gcr.io/kpt-fn/set-enforcement-action:v0.1 \
      -- enforcementAction=dryrun
    
  4. 使用 kpt 初始化工作目录,此操作会创建一个资源来跟踪更改:

    cd cis-k8s-v1.5.1
    kpt live init
    
  5. 使用 kpt 应用政策限制条件:

    kpt live apply
    

    输出如下所示:

    k8spspseccomp.constraints.gatekeeper.sh/psp-seccomp-docker-default created
    k8spodsrequiresecuritycontext.constraints.gatekeeper.sh/pods-require-security-context created
    k8sprohibitrolewildcardaccess.constraints.gatekeeper.sh/prohibit-role-wildcard-access created
    k8srequirenamespacenetworkpolicies.constraints.gatekeeper.sh/require-namespace-network-policies created
    k8snoenvvarsecrets.constraints.gatekeeper.sh/no-secrets-as-env-vars created
    k8spspallowprivilegeescalationcontainer.constraints.gatekeeper.sh/psp-allow-privilege-escalation-container created
    k8spspallowedusers.constraints.gatekeeper.sh/psp-pods-must-run-as-nonroot created
    k8spsphostnetworkingports.constraints.gatekeeper.sh/psp-host-network-ports created
    k8srestrictrolebindings.constraints.gatekeeper.sh/restrict-clusteradmin-rolebindings created
    k8spspcapabilities.constraints.gatekeeper.sh/psp-capabilities created
    k8spsphostnamespace.constraints.gatekeeper.sh/psp-host-namespace created
    k8spspprivilegedcontainer.constraints.gatekeeper.sh/psp-privileged-container created
    13 resource(s) applied. 13 created, 0 unchanged, 0 configured, 0 failed
    
  6. 验证政策限制条件是否已安装,并检查集群中是否存在违规行为:

    kpt live status --output table --poll-until current
    

    状态为 CURRENT,即确认限制条件成功安装。

Config Sync

  1. 安装并设置 kpt。在这些说明中,kpt 用于自定义和部署 Kubernetes 资源。

  2. 如果您是第一次使用 Anthos Config Management,请启用 Anthos Config Management

使用 Config Sync 将政策部署到其集群的运维人员可以按照以下说明操作:

  1. 更改为 Config Sync 的同步目录:

    cd SYNC_ROOT_DIR
    
  2. 创建一个专用的 policies 目录:

    mkdir -p policies
    
  3. 使用 kpt 从 GitHub 下载 CIS 政策软件包:

    kpt pkg get https://github.com/GoogleCloudPlatform/acm-policy-controller-library.git/bundles/cis-k8s-v1.5.1 policies/cis-k8s-v1.5.1
    
  4. 运行 set-enforcement-action kpt 函数将政策的强制执行操作设置为 dryrun

    kpt fn eval policies/cis-k8s-v1.5.1 -i gcr.io/kpt-fn/set-enforcement-action:v0.1 -- enforcementAction=dryrun
    
  5. (可选)预览将创建的政策限制条件:

    kpt live init policies/cis-k8s-v1.5.1
    kpt live apply --dry-run policies/cis-k8s-v1.5.1
    

    输出如下所示:

    Dry-run strategy: client
    inventory update started
    inventory update finished
    apply phase started
    k8snoenvvarsecrets.constraints.gatekeeper.sh/cis-k8s-v1.5.1-no-secrets-as-env-vars apply successful
    k8spspallowprivilegeescalationcontainer.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-allow-privilege-escalation apply successful
    k8spspallowedusers.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-pods-must-run-as-nonroot apply successful
    k8spspcapabilities.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-capabilities apply successful
    k8spsphostnamespace.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-host-namespace apply successful
    k8spsphostnetworkingports.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-host-network-ports apply successful
    k8spspprivilegedcontainer.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-privileged-container apply successful
    k8spspseccomp.constraints.gatekeeper.sh/cis-k8s-v1.5.1-psp-seccomp-default apply successful
    k8spodsrequiresecuritycontext.constraints.gatekeeper.sh/cis-k8s-v1.5.1-pods-require-security-context apply successful
    k8sprohibitrolewildcardaccess.constraints.gatekeeper.sh/cis-k8s-v1.5.1-prohibit-role-wildcard-access apply successful
    k8srequirenamespacenetworkpolicies.constraints.gatekeeper.sh/cis-k8s-v1.5.1-require-namespace-network-policies apply successful
    k8srestrictrolebindings.constraints.gatekeeper.sh/cis-k8s-v1.5.1-restrict-clusteradmin-rolebindings apply successful
    apply phase finished
    inventory update started
    inventory update finished
    apply result: 12 attempted, 12 successful, 0 skipped, 0 failed
    
  6. 如果 Config Sync 的同步目录使用 Kustomize,请将 policies/cis-k8s-v1.5.1 添加到根 kustomization.yaml。否则,请移除 policies/cis-k8s-v1.5.1/kustomization.yaml 文件:

    rm SYNC_ROOT_DIR/policies/cis-k8s-v1.5.1/kustomization.yaml
    
  7. 将更改推送到 Config Sync 代码库:

    git add SYNC_ROOT_DIR/policies/cis-k8s-v1.5.1
    git commit -m 'Adding CIS policy audit enforcement'
    git push
    
  8. 验证安装状态:

    watch gcloud beta container fleet config-management status --project PROJECT_ID
    

    状态 SYNCED 用于确认政策的安装情况。

查看违规问题

在审核模式下安装政策限制条件后,您可以使用政策控制器信息中心在界面中查看集群的违规问题。

您还可以使用 kubectl 来通过以下命令查看针对集群的违规行为:

kubectl get constraint -l policycontroller.gke.io/bundleName=cis-k8s-v1.5.1 -o json | jq -cC '.items[]| [.metadata.name,.status.totalViolations]'

如果存在违规行为,您可以使用以下命令查看每个限制条件的违规消息列表:

kubectl get constraint -l policycontroller.gke.io/bundleName=cis-k8s-v1.5.1 -o json | jq -C '.items[]| select(.status.totalViolations>0)| [.metadata.name,.status.violations[]?]'

实施 CIS 政策

查看集群中的政策违规后,下一步就是强制执行这些政策,以使准入控制器阻止任何不合规的资源应用于集群。

kubectl

  1. 使用 kubectl 将政策的强制执行操作设置为 deny

    kubectl get constraint -l policycontroller.gke.io/bundleName=cis-k8s-v1.5.1 -o json | jq '.items[].spec.enforcementAction="deny"' | kubectl apply -f -
    
  2. 验证政策限制条件强制执行措施是否已更新:

    kubectl get -k https://github.com/GoogleCloudPlatform/acm-policy-controller-library.git/bundles/cis-k8s-v1.5.1
    

kpt

  1. 运行 set-enforcement-action kpt 函数将政策的强制执行操作设置为 deny

    kpt fn eval -i gcr.io/kpt-fn/set-enforcement-action:v0.1 -- enforcementAction=deny
    
  2. 应用政策限制条件:

    kpt live apply
    

Config Sync

使用 Config Sync 将政策部署到其集群的运维人员可以按照以下说明操作:

  1. 更改为 Config Sync 的同步目录:

    cd SYNC_ROOT_DIR
    
  2. 运行 set-enforcement-action kpt 函数将政策的强制执行操作设置为 deny

    kpt fn eval policies/cis-k8s-v1.5.1 -i gcr.io/kpt-fn/set-enforcement-action:v0.1 -- enforcementAction=deny
    
  3. 将更改推送到 Config Sync 代码库:

    git add SYNC_ROOT_DIR/policies/cis-k8s-v1.5.1
    git commit -m 'Enforcing CIS policies for GKE'
    git push
    
  4. 验证安装状态:

    gcloud alpha anthos config sync repo list --project PROJECT_ID
    

    SYNCED 列中显示的代码库将确认政策的安装情况。

测试政策执行情况

执行快速测试以确认政策执行和对集群上不合规资源的阻止。

使用以下命令在集群上创建不合规的资源:

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  namespace: default
  name: wp-non-compliant
  labels:
    app: wordpress
spec:
  containers:
    - image: wordpress
      name: wordpress
      ports:
      - containerPort: 80
        name: wordpress
EOF

准入控制器应生成一个错误,其中列出了此资源违反政策的行为。 例如:

Error from server (Forbidden): error when creating "STDIN": admission webhook "validation.gatekeeper.sh" denied the request:
[cis-k8s-v1.5.1-psp-pods-must-run-as-nonroot] Container wordpress is attempting to run without a required securityContext/runAsNonRoot or securityContext/runAsUser != 0
[cis-k8s-v1.5.1-psp-allow-privilege-escalation] Privilege escalation container is not allowed: wordpress
[cis-k8s-v1.5.1-psp-seccomp-default] Seccomp profile 'not configured' is not allowed for container 'wordpress'. Found at: no explicit profile found. Allowed profiles: {"RuntimeDefault", "docker/default", "runtime/default"}
[cis-k8s-v1.5.1-psp-capabilities] container  is not dropping all required capabilities. Container must drop all of ["NET_RAW"] or "ALL"
[cis-k8s-v1.5.1-pods-require-security-context] securityContext must be defined for all Pod containers