Istio：服务发现和Pilot的架构机制

刺骨的言语ヽ痛彻心扉 2023-06-29 10:43 8阅读 0赞

# 大纲 #

> Istio架构&Pilot介绍  
> Istio服务发现  
> Istio服务配置  
> stio服务发现&规则管理与Kubernetes结合  
> ShowCase

Istio架构&Pilot介绍

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70][] Istio架构

## Pilot功能 ##

>  *  服务发现
>  *  服务配置

# Istio服务发现 #

## 服务发现基本原理     ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 1][]

> a.app 88.88.88.66  
> a.app 88.88.88.77  
> a.app 88.88.88.88
> 
>   
> b.app 88.88.88.99  
> b.app 88.88.88.55

## SpringCloud的服务(注册与)发现流程 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 2][]

>  *  **服务注册表：**如Springcloud中一般Eureka服务；
>  *  **服务注册：**服务配置文件中配置服务名和本实例地址，实例启动时自动注册到服务注册表；
>  *  **服务发现：**访问目标服务时连服务注册表，获取服务实例列表。根据LB根据策略选择一个服务实例，建立连接去访问。

## Istio服务发现流程 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 3][] Istio服务发现流程

>  *  **服务注册表：** Pilot 从平台获取服务发现数据， 并提供统一的服务发现接口。
>  *  **服务注册：**无
>  *  **服务发现：** Envoy 实现服务发现，动态更新负载均衡池。在服务请求时使用对应的负载均衡策略将请求路由到对应的后端。

## Pilot服务发现机制的Adapter机制 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 4][]

## Istio服务发现实现：基于 Eureka ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 5][]

> 1. Pilot 实现若干服务发现的接口定义  
> 2. Controller使用EurekaClient来获取服务列表， 提供转换后的标准的服务发现接口和数据结构；  
> 3. Discoveryserver基于Controller上维护的服务发现数据， 发布成gRPC协议的服务供Envoy使用。  
> 4. 当 有 服 务 访 问 时 ， Envoy 在 处 理Outbound请求时， 根据配置的LB策略，选择一个服务实例发起访问

## Istio 服务发现实现：基于Kubernetes ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 6][]

> 1. Pilot 实现若干服务发现的接口定义  
> 2. Pilot 的Controller List/WatchKubeAPIserver上service、endpoint等资源对象并转换成标准格式。  
> 3. Envoy从Pilot获取xDS，动态更新  
> 4. 当有服务访问时， Envoy在处理Outbound请求时，根据配置的LB策略，选择一个服务实例发起访问。

## Kubernetes & Istio 服务模型 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 7][]

## Kuberntes的服务发现 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 8][]

## Istio Upon Kubernetes场景 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 9][] Istio Upon Kubernetes场景

## Istio （ upon Kubernetes）服务发现和配置 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 10][] Istio （ upon Kubernetes）服务发现和配置

# Istio服务配置管理 #

## Istio 服务访问规则维护和工作机制 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 11][] Istio 服务访问规则维护和工作机制

>  *  1. 配置：管理员通过Pilot配置治理规则
>  *  2. 下发： Envoy从Pilot获取治理规则
>  *  3. 执行：在流量访问的时候执行治理规则

## Istio治理规则 ##

>  *  VirtualService
>  *   DestinationRule
>  *  Gateway
>  *   ServiceEntry
>  *   …
> 
> [https://istio.io/docs/reference/config/istio.networking.v1alpha3/][https_istio.io_docs_reference_config_istio.networking.v1alpha3]

## Istio流量规则： VirtualService ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 12][] Istio流量规则： VirtualService

## Istio流量规则： DestinationRule ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 13][] Istio流量规则： DestinationRule

## Istio流量规则： ServiceEntry & Gateway ##

> **ServiceEntry：**
> 
>  *  功能： Mesh外的服务加入到服务发现中，向Mesh里面的服务一样的被治理
>  *  机制： 将ServiceEntry描述的服务加入到服务发现中；对这些服务的outbound流量进行拦截，进而进行治理
> 
> **Gateway：**
> 
>  *  功能：将mesh内的一个服务发布成可供外部访问。
>  *  机制：在入口处部署一个ingress的Envoy，在其上执行服务治理。

## Istio配置规则维护和下发流程 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 14][]

## 治理规则定义 Istio VS Envoy     ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 15][] Istio 规则

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 16][] Envoy规则

## Istio治理能力执行位置 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 17][]

# Istio服务发现&规则管理与Kubernetes结合 #

## Kubernetes & Istio 结合 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 18][]

## 服务发现和配置管理： Istio+K8S ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 19][]

## 服务发现和配置管理： Spring Cloud+K8S ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZseTkxMDkwNQ_size_16_color_FFFFFF_t_70 20][]

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[https_istio.io_docs_reference_config_istio.networking.v1alpha3]: https://istio.io/docs/reference/config/istio.networking.v1alpha3/
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