# 生成 K8s 审计日志

默认 Kubernetes 集群不会生成审计日志信息。通过以下配置，可以开启 Kubernetes 的审计日志功能。

!!! note

    公有云环境中可能无法控制 Kubernetes 审计日志输出及输出路径。

1. 准备审计日志的 Policy 文件
2. 配置 API 服务器，开启审计日志
3. 重启并验证

## 准备审计日志 Policy 文件

<details>
  <summary>点击查看 policy.yaml 完整内容</summary>

  <pre><code>apiVersion: audit.k8s.io/v1
kind: Policy
rules:
  # The following requests were manually identified as high-volume and low-risk,
  # so drop them.
  - level: None
    users: ["system:kube-proxy"]
    verbs: ["watch"]
    resources:
      - group: "" # core
        resources: ["endpoints", "services", "services/status"]
  - level: None
    # Ingress controller reads `configmaps/ingress-uid` through the unsecured port.
    # TODO(#46983): Change this to the ingress controller service account.
    users: ["system:unsecured"]
    namespaces: ["kube-system"]
    verbs: ["get"]
    resources:
      - group: "" # core
        resources: ["configmaps"]
  - level: None
    users: ["kubelet"] # legacy kubelet identity
    verbs: ["get"]
    resources:
      - group: "" # core
        resources: ["nodes", "nodes/status"]
  - level: None
    userGroups: ["system:nodes"]
    verbs: ["get"]
    resources:
      - group: "" # core
        resources: ["nodes", "nodes/status"]
  - level: None
    users:
      - system:kube-controller-manager
      - system:kube-scheduler
      - system:serviceaccount:kube-system:endpoint-controller
    verbs: ["get", "update"]
    namespaces: ["kube-system"]
    resources:
      - group: "" # core
        resources: ["endpoints"]
  - level: None
    users: ["system:apiserver"]
    verbs: ["get"]
    resources:
      - group: "" # core
        resources: ["namespaces", "namespaces/status", "namespaces/finalize"]
  # Don't log HPA fetching metrics.
  - level: None
    users:
      - system:kube-controller-manager
    verbs: ["get", "list"]
    resources:
      - group: "metrics.k8s.io"
  # Don't log these read-only URLs.
  - level: None
    nonResourceURLs:
      - /healthz*
      - /version
      - /swagger*
  # Don't log events requests.
  - level: None
    resources:
      - group: "" # core
        resources: ["events"]
  # Secrets, ConfigMaps, TokenRequest and TokenReviews can contain sensitive & binary data,
  # so only log at the Metadata level.
  - level: Metadata
    resources:
      - group: "" # core
        resources: ["secrets", "configmaps", "serviceaccounts/token"]
      - group: authentication.k8s.io
        resources: ["tokenreviews"]
    omitStages:
      - "RequestReceived"
  # Get responses can be large; skip them.
  - level: Request
    verbs: ["get", "list", "watch"]
    resources:
      - group: "" # core
      - group: "admissionregistration.k8s.io"
      - group: "apiextensions.k8s.io"
      - group: "apiregistration.k8s.io"
      - group: "apps"
      - group: "authentication.k8s.io"
      - group: "authorization.k8s.io"
      - group: "autoscaling"
      - group: "batch"
      - group: "certificates.k8s.io"
      - group: "extensions"
      - group: "metrics.k8s.io"
      - group: "networking.k8s.io"
      - group: "policy"
      - group: "rbac.authorization.k8s.io"
      - group: "settings.k8s.io"
      - group: "storage.k8s.io"
    omitStages:
      - "RequestReceived"
  # Default level for known APIs
  - level: RequestResponse
    resources:
      - group: "" # core
      - group: "admissionregistration.k8s.io"
      - group: "apiextensions.k8s.io"
      - group: "apiregistration.k8s.io"
      - group: "apps"
      - group: "authentication.k8s.io"
      - group: "authorization.k8s.io"
      - group: "autoscaling"
      - group: "batch"
      - group: "certificates.k8s.io"
      - group: "extensions"
      - group: "metrics.k8s.io"
      - group: "networking.k8s.io"
      - group: "policy"
      - group: "rbac.authorization.k8s.io"
      - group: "settings.k8s.io"
      - group: "storage.k8s.io"
    omitStages:
      - "RequestReceived"
  # Default level for all other requests.
  - level: Metadata
    omitStages:
      - "RequestReceived"
  </code></pre>
</details>

将以上审计日志文件放到 __/etc/kubernetes/audit-policy/__ 文件夹下，并取名为 __apiserver-audit-policy.yaml__ 。

## 配置 API 服务器

打开 API 服务器的配置文件 kube-apiserver.yaml ，一般会在 __/etc/kubernetes/manifests/__ 文件夹下，并添加以下配置信息：

这一步操作前请备份 kube-apiserver.yaml ，并且备份的文件不能放在 __/etc/kubernetes/manifests/__ 下，建议放在 __/etc/kubernetes/tmp__ 。

1. 在 __spec.containers.command__ 下添加命令：

    ```yaml
    --audit-log-maxage=30
    --audit-log-maxbackup=10
    --audit-log-maxsize=100
    --audit-log-path=/var/log/audit/kube-apiserver-audit.log
    --audit-policy-file=/etc/kubernetes/audit-policy/apiserver-audit-policy.yaml
    ```

2. 在 __spec.containers.volumeMounts__ 下添加：

    ```yaml
    - mountPath: /var/log/audit
      name: audit-logs
    - mountPath: /etc/kubernetes/audit-policy
      name: audit-policy
    ```

3. 在 __spec.volumes__ 下添加：

    ```yaml
    - hostPath:
        path: /var/log/kubernetes/audit
        type: ""
      name: audit-logs
    - hostPath:
        path: /etc/kubernetes/audit-policy
        type: ""
      name: audit-policy
    ```

## 测试并验证

稍等一会，API 服务器会自动重启，执行以下命令查看 __/var/log/kubernetes/audit__ 目录下是否有审计日志生成，若有，则表示 K8s 审计日志成功开启。

```shell
ls /var/log/kubernetes/audit
```

如果想关闭，去掉 __spec.containers.command__ 中的相关命令即可。