ValidatingWebhookConfiguration 设计说明
ValidatingWebhookConfiguration的设计主要作用是在Kubernetes中实现请求的验证功能。它允许管理员定义一组验证webhooks，用于检查和修改Kubernetes对象的请求是否符合指定的规则。ValidatingWebhookConfiguration的设计主要目的是增强Kubernetes集群的安全性和可靠性。
摘要
ValidatingWebhookConfiguration的主要作用包括：
- 请求验证：通过配置验证webhooks，可以对将被提交到Kubernetes集群中的请求进行验证。例如，可以验证请求的结构、格式、内容和安全性等方面。
- 实施策略规则：ValidatingWebhookConfiguration允许管理员创建和配置验证规则，以根据需要对请求进行校验。这些验证规则可以基于资源对象的类型、注解、标签或其他属性等进行定义。
- 集中化管理：ValidatingWebhookConfiguration提供了集中化的管理和配置验证webhooks的机制。管理员可以通过创建和管理ValidatingWebhookConfiguration对象来集中管理整个集群中的请求验证逻辑，而无需分散在各个应用或服务中实现验证逻辑。
- 增加安全性：通过ValidatingWebhookConfiguration，可以防止恶意或无效的请求被提交到Kubernetes集群中。管理员可以定义一组验证规则，以确保请求的正确性、合规性和安全性，从而增加集群的安全性。
- 增强可靠性：ValidatingWebhookConfiguration可以在请求提交到集群之前对其进行验证，并拒绝不符合验证规则的请求。这样可以减少不正确或不完整的请求进入集群，增加系统的可靠性。
总结： 通过ValidatingWebhookConfiguration的设计，管理员可以根据自定义的验证规则对Kubernetes集群中的请求进行验证。它可以帮助提高集群的安全性和可靠性，保证被提交的请求符合指定的规则，从而提供更加稳定和安全的应用部署和管理环境。
自定义策略
ValidatingWebhookConfiguration 允许您定义验证失败处理策略，以控制当 Kubernetes 中的验证 Webhook 失败时的行为。
验证 Webhook 是在提交到 Kubernetes API 服务器之前对请求进行验证的一种机制。它可以用于检查请求的数据和结构是否符合特定的规则或策略。如果验证不通过，请求将被拒绝并返回错误消息。
当一个验证 Webhook 失败时，可以通过 ValidatingWebhookConfiguration 来定义处理策略。以下是一些常见的处理策略：
- Ignore：忽略验证失败，允许请求继续进行处理。这意味着不会阻止请求的提交，即使验证失败。这种策略可能会导致安全风险，因为请求可能会绕过验证。
- Fail：请求失败，并返回一个错误消息，拒绝请求。这是最常见的处理策略，它确保只有符合验证规则的请求才被接受。
- Warn：请求失败，并返回一个警告消息，但仍允许请求继续。这种策略可以在验证失败的情况下提供一些提示，但不会阻止请求的提交。
- Custom：自定义策略允许您通过指定自定义的处理函数来处理验证失败情况。这样，您可以定义自己的处理逻辑，例如记录验证失败日志、发送通知等。
可以根据您的需求选择适合的处理策略。建议在生产环境中使用严格的处理策略，例如 Fail 或 Warn，以确保请求的安全性和符合预期的验证规则。同时，您还可以根据验证失败的原因，通过日志记录和监控来进一步调查和处理验证失败情况。
CA 配置
- CA Bundle验证：Kubernetes可以配置一个包含所有信任的CA证书的CA Bundle集合，用于验证webhook服务的证书。当Kubernetes与验证webhook服务建立TLS连接时，会使用配置的CA Bundle集合来验证验证webhook服务证书的合法性。
Simply put
The primary purpose of ValidatingWebhookConfiguration is to enable request validation in Kubernetes. It allows administrators to define a collection of validating webhooks that can inspect and modify requests to Kubernetes objects, ensuring they adhere to specific rules. The design of ValidatingWebhookConfiguration serves to enhance the security and reliability of Kubernetes clusters.
The key roles and benefits of ValidatingWebhookConfiguration design include:
- Request Validation: By configuring validating webhooks, requests submitted to the Kubernetes cluster can be validated. This enables validation of request structure, format, content, and security aspects, among others.
- Enforcement of Policy Rules: ValidatingWebhookConfiguration facilitates the creation and configuration of validation rules to ensure requests comply with specific requirements. These rules can be based on resource object types, annotations, labels, or other attributes as defined by administrators.
- Centralized Management: ValidatingWebhookConfiguration provides a centralized mechanism for administrators to manage and configure validating webhooks. It allows them to centrally control and enforce request validation logic across the cluster, rather than implementing validation logic in multiple applications or services.
- Enhanced Security: ValidatingWebhookConfiguration helps prevent malicious or invalid requests from being submitted to the Kubernetes cluster. Administrators can define a set of validation rules to ensure the correctness, compliance, and security of requests, thereby boosting cluster security.
- Improved Reliability: ValidatingWebhookConfiguration allows requests to be validated before they are submitted to the cluster, rejecting any requests that do not meet the validation rules. This reduces the likelihood of incorrect or incomplete requests entering the cluster, thus enhancing system reliability.
In summary, the design of ValidatingWebhookConfiguration enables request validation in Kubernetes by defining and enforcing validation rules. It contributes to a more secure and reliable environment for deploying and managing applications within the cluster.
Example
下面是一个ValidatingWebhookConfiguration在Kubernetes上的使用示例：
- 创建一个验证webhook的服务：
apiVersion: v1
kind: Service
metadata:
name: validation-webhook-service
spec:
selector:
app: validation-webhook
ports:
- name: http
port: 8080
- 创建ValidatingWebhookConfiguration对象：
apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingWebhookConfiguration
metadata:
name: example-validation-webhook
webhooks:
- name: example-validation-webhook
clientConfig:
url: https://validation-webhook-service/validate
caBundle: >
rules:
- apiGroups: [""]
apiVersions: ["v1"]
operations: ["CREATE", "UPDATE"]
resources: ["pods"]
failurePolicy: Fail
- 在
clientConfig中，指定了验证webhook服务的URL，其中https://validation-webhook-service/validate是上一步创建的服务的URL。同时，caBundle字段中需要填入用于验证Webhook服务证书的 CA Bundle。 - 在
rules中，指定了要应用验证规则的资源对象，这里例子中指定了只对Pod资源进行验证。 failurePolicy指定了验证失败的处理策略，这里例子中设置为Fail，即验证失败时拒绝请求。- 部署ValidatingWebhookConfiguration对象到Kubernetes集群：
kubectlapply-fvalidating-webhook-config.yaml
- 等待Webhook生效并验证请求：
- 部署完成后，ValidatingWebhookConfiguration将在Kubernetes控制平面生效。
- 当有创建或更新Pod的请求时，Kubernetes将在发送请求之前将其发送至验证webhook服务进行验证。
- 验证结果将在验证webhook服务的日志中可见，同时根据验证的 policy，可以阻止或允许请求进入集群。
这个示例演示了如何在Kubernetes中配置并使用ValidatingWebhookConfiguration来验证Pod资源的请求。您可以根据特定的需求和场景，修改验证规则和逻辑来满足您的需求。
On the other hand
Once upon a time in a distant future, there was a planet called K8s. The inhabitants of K8s were highly advanced and had created a system called ValidatingWebhookConfiguration to ensure the safety and validity of their virtual world.
The ValidatingWebhookConfiguration acted like a sentinel, constantly scanning incoming information and verifying its authenticity. It was designed to protect K8s from any malicious or suspicious activities that could threaten the stability of their world.
Like a great wizard, the ValidatingWebhookConfiguration used its magic to cast spells and incantations on the data, analyzing its every aspect and ensuring it met the highest standards of quality. Any information that did not pass the tests was immediately flagged and reported back to the inhabitants of K8s for further investigation.
Thanks to the powerful ValidatingWebhookConfiguration, the people of K8s could rest easy knowing that their virtual world was secure from any threats lurking in the shadows. It was a crucial piece of technology that ensured their peace of mind and allowed them to focus on creating even greater wonders and innovations for their future.