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在 Kubernetes 的世界中，我们使用 YAML 文件，对其进行部署以创建各种 Kubernetes 对象，但挑战在于编写它们时是否遵循最佳实践？我们使用的是正确的标准配置集吗？在部署应用程序甚至 Helm 图表之前，可以检查 YAML 吗？所有这些问题的答案都是肯定的，我们可以。2020年10月28日，StackRox 引入了一个名为 KubeLinter 的新开源工具，旨在识别 YAML 文件中的任何错误配置。

根据定义，KubeLinter 是一个静态分析工具，用于检查 Kubernetes YAML 文件和 Helm 图表，以确保其中所代表的应用程序遵循最佳实践。将 YAML 文件提供给该工具后，它将通过内置检查运行，然后详细报告任何错误以及解决这些错误的补救措施。关于此工具的最好之处在于它是可配置和可扩展的：可以启用或禁用内置检查，并且您可以定义和使用自己的自定义检查。

用法

我将在 Mac 上安装 KubeLinter，但只需下载适用于您操作系统的发行版，即可将相同的说明用于Linux。

你可以从https://github.com/stackrox/kube-linter/releases/下载 KubeLinter CLI，如下所示：

$ curl -LO https://github.com/stackrox/kube-linter/releases/download/0.1.1/kube-linter-darwin.zip
$ unzip kube-linter-darwin.zip
$ mv kube-linter /usr/local/bin#check if it's working
$ kube-linter version
0.1.1

现在，为了简单地检查单个 YAML 文件，只需提供 YAML 文件名。假设 deploy.yaml 您要检查以下文件，以检查其当前目录中保存的最佳安全性和配置做法：

apiVersion: apps/v1
kind: Deployment
metadata:name: portainernamespace: portainerlabels:io.portainer.kubernetes.application.stack: portainerapp.kubernetes.io/name: portainerapp.kubernetes.io/instance: portainerapp.kubernetes.io/version: "2.0.0"
spec:replicas: 1strategy:type: "Recreate"selector:matchLabels:app.kubernetes.io/name: portainerapp.kubernetes.io/instance: portainertemplate:metadata:labels:app.kubernetes.io/name: portainerapp.kubernetes.io/instance: portainerspec:serviceAccountName: portainer-sa-clusteradminvolumes:- name: "data"persistentVolumeClaim:claimName: portainercontainers:- name: portainerimage: "portainer/portainer-ce:latest"imagePullPolicy: IfNotPresentargs:  [ '--tunnel-port','30776' ]volumeMounts:- name: datamountPath: /dataports:- name: httpcontainerPort: 9000protocol: TCP- name: tcp-edgecontainerPort: 8000protocol: TCPlivenessProbe:httpGet:path: /port: 9000readinessProbe:httpGet:path: /port: 9000resources:{}

让我们进行测试 kube-linter lint deploy.yaml。我们应该得到如下输出：

deploy.yaml: (object: portainer/portainer apps/v1, Kind=Deployment) container "portainer" does not have a read-only root file system (check: no-read-only-root-fs, remediation: Set readOnlyRootFilesystem to true in your container's securityContext.)deploy.yaml: (object: portainer/portainer apps/v1, Kind=Deployment) serviceAccount "portainer-sa-clusteradmin" not found (check: non-existent-service-account, remediation: Make sure to create the service account, or to refer to an existing service account.)deploy.yaml: (object: portainer/portainer apps/v1, Kind=Deployment) container "portainer" is not set to runAsNonRoot (check: run-as-non-root, remediation: Set runAsUser to a non-zero number, and runAsNonRoot to true, in your pod or container securityContext. See https://kubernetes.io/docs/tasks/configure-pod-container/security-context/ for more details.)deploy.yaml: (object: portainer/portainer apps/v1, Kind=Deployment) container "portainer" has cpu request 0 (check: unset-cpu-requirements, remediation: Set your container's CPU requests and limits depending on its requirements. See https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#requests-and-limits for more details.)deploy.yaml: (object: portainer/portainer apps/v1, Kind=Deployment) container "portainer" has cpu limit 0 (check: unset-cpu-requirements, remediation: Set your container's CPU requests and limits depending on its requirements. See https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#requests-and-limits for more details.)deploy.yaml: (object: portainer/portainer apps/v1, Kind=Deployment) container "portainer" has memory request 0 (check: unset-memory-requirements, remediation: Set your container's memory requests and limits depending on its requirements. See https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#requests-and-limits for more details.)deploy.yaml: (object: portainer/portainer apps/v1, Kind=Deployment) container "portainer" has memory limit 0 (check: unset-memory-requirements, remediation: Set your container's memory requests and limits depending on its requirements. See https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#requests-and-limits for more details.)Error: found 7 lint errors

检测类型

如您所见，YAML 文件中发现了错误，每个错误都有明确的补救步骤。

如果您想看一下内置检查，可以在https://github.com/stackrox/kube-linter/blob/main/docs/genic/checks.md中列出所有这些检查，或者也可以使用 KubeLinter 查看清单：

$ kube-linter checks list
Name: dangling-service
Description: Alert on services that don't have any matching deployments
Remediation: Make sure your service's selector correctly matches the labels on one of your deployments.
Template: dangling-service
Parameters: map[]
Enabled by default: true------------------------------Name: default-service-account
Description: Alert on pods that use the default service account
Remediation: Create a dedicated service account for your pod. See https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/ for more details.
Template: service-account
Parameters: map[serviceAccount:^(|default)$]
Enabled by default: false
|
|
|
and many more

忽略检测

您可以使用以下注释忽略针对 YAML 文件的特定检查，也可以根据需要忽略检查组：

ignore-check.kube-linter.io/<check-name>

例如：

ignore-check.kube-linter.io/unset-cpu-requirements

您可以像上面这样在上面的部署文件示例中添加忽略检查规则：

metadata:name: portainernamespace: portainerlabels:io.portainer.kubernetes.application.stack: portainerapp.kubernetes.io/name: portainerapp.kubernetes.io/instance: portainerapp.kubernetes.io/version: "2.0.0"annotations:ignore-check.kube-linter.io/unset-cpu-requirements : "cpu requirements not required"

现在，当您 kube-linter lint deploy.yaml 再次运行时，您应该不会看到与 CPU 要求相关的错误提示。

使用配置运行

KubeLinter 也可以使用配置运行，您可以在其中提供要包含/排除的所有检测信息。以下是存储库中的示例配置：

# customChecks defines custom checks.
customChecks:
- name: "required-label-app"template: "required-label"params:key: "app"
checks:# if doNotAutoAddDefaults is true, default checks are not automatically added.doNotAutoAddDefaults: false# addAllBuiltIn, if set, adds all built-in checks. This allows users to# explicitly opt-out of checks that are not relevant using Exclude.# Takes precedence over doNotAutoAddDefaults, if both are set.addAllBuiltIn: false# include explicitly adds checks, by name. You can reference any of the built-in checks.# Note that customChecks defined above are included automatically.include:- "required-label-owner"# exclude explicitly excludes checks, by name. exclude has the highest priority: if a check is# in exclude, then it is not considered, even if it is in include as well.exclude:- "privileged"

如果你运行kubelinter --config config lint deploy.yaml，其中 config 与上述配置的文件，你应该可以看到添加了需要标签的检查：

deploy.yaml: (object: portainer/portainer apps/v1, Kind=Deployment) no label matching "owner=<any>" found (check: required-label-owner, remediation: Add an email annotation to your object with information about the object's owner.)

当内置到 CI 管道中时，KubeLinter 可以证明是非常有用的工具。可以检查和验证推送到存储库中的编排文件，以获取最佳实践和安全考虑，并在检测到问题时生成警报。

这样，可以将部署到集群的应用程序进行健康的就绪检查。该项目处于 Alpha 阶段，但有望作为 CI 集成工具在实际部署到生产之前验证所有部署。