中文
策略管理
Mixer 为应用程序和基础架构后端之间提供了一个通用的策略控制层，负责先决条件检查（如认证授权）、配额管理并从 Envoy 代理中收集遥测数据等。
Mixer 是高度模块化和可扩展的组件。他的一个关键功能就是把不同后端的策略和遥测收集系统的细节抽象出来，使得 Istio 的其余部分对这些后端不知情。Mixer 处理不同基础设施后端的灵活性是通过使用通用插件模型实现的。每个插件都被称为 Adapter，Mixer通过它们与不同的基础设施后端连接，这些后端可提供核心功能，例如日志、监控、配额、ACL 检查等。通过配置能够决定在运行时使用的确切的适配器套件，并且可以轻松扩展到新的或定制的基础设施后端。
实现原理
- 通过全局 Adapters 为请求引入新的属性
- 通过解析（Resolution）识别要用于处理请求的配置资源
- 处理属性，生成 Adapter 参数
- 分发请求到各个 Adapters 后端处理
流量限制示例
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apiVersion: "config.istio.io/v1alpha2"
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kind: memquota
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metadata:
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name: handler
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namespace: istio-system
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spec:
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quotas:
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- name: requestcount.quota.istio-system
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maxAmount: 5000
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validDuration: 1s
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# The first matching override is applied.
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# A requestcount instance is checked against override dimensions.
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overrides:
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# The following override applies to 'ratings' when
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# the source is 'reviews'.
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- dimensions:
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destination: ratings
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source: reviews
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maxAmount: 1
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validDuration: 1s
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# The following override applies to 'ratings' regardless
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# of the source.
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- dimensions:
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destination: ratings
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maxAmount: 100
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validDuration: 1s
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---
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apiVersion: "config.istio.io/v1alpha2"
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kind: quota
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metadata:
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name: requestcount
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namespace: istio-system
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spec:
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dimensions:
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source: source.labels["app"] | source.service | "unknown"
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sourceVersion: source.labels["version"] | "unknown"
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destination: destination.labels["app"] | destination.service | "unknown"
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destinationVersion: destination.labels["version"] | "unknown"
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---
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apiVersion: "config.istio.io/v1alpha2"
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kind: rule
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metadata:
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name: quota
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namespace: istio-system
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spec:
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actions:
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- handler: handler.memquota
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instances:
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- requestcount.quota
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---
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apiVersion: config.istio.io/v1alpha2
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kind: QuotaSpec
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metadata:
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name: request-count
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namespace: istio-system
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spec:
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rules:
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- quotas:
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- charge: 1
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quota: requestcount
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---
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apiVersion: config.istio.io/v1alpha2
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kind: QuotaSpecBinding
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metadata:
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name: request-count
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namespace: istio-system
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spec:
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quotaSpecs:
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- name: request-count
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namespace: istio-system
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services:
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- name: ratings
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- name: reviews
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- name: details
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- name: productpage
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