Details of istio micro service governance grid traffic management core resource controller

Istio Microservice governance grid traffic management core resource controller details

1.Istio Traffic management core resource controller

Istio There are four common traffic management resources ：

• Gateway（ Gateway resources ）
• VirtualService（ Virtual service resources ）
• DestinationRule（ Target rule resource ）
• ServiceEntry（ Service portal resources ）

Istio Forwarding traffic in 、 Access control 、 Grayscale publishing and other functions are realized by writing these four resource layout files .

2.Gateway Gateway resources

2.1.Gateway The concept of resources

Gateway Gateway resources are mainly used to provide an external access portal for services in the grid , Be similar to Ingress resources , Publish applications in the grid in the Internet environment .

Gateway Gateway resources need to be configured VirtualService Resources can complete the rule configuration information exposed by the application ,Gateway And VirtualService The defined forwarding rules will eventually be configured in Istio Of Ingressgateway In service .

Gateway Gateway resources can manage the traffic at the entrance and exit , Forward requests to specific applications , According to the direction of inflow and outflow, it can be divided into the following two types ：

• IngressGateway： It is mainly responsible for receiving external traffic requests , Then forward the traffic to an application in the grid .
• EngressGateway： Services inside the grid need to access external applications .

Gateway The flow forwarding diagram of is shown in the figure below .

2.2.Gateway Resource list file

apiVersion: networking.istio.io/v1alpha3
kind: Gateway							# The resource type is Gateway
metadata:
  name: httpbin-gateway					# The name of the resource 
spec:
  selector:							# Define selector 
    istio: ingressgateway				# relation istio Of ingressgateway
  servers:								# Define the service list 
  - port:								# Define the port number used by the service 
      number: 80						# The port number is 80
      name: http						# The name of the port 
      protocol: HTTP					# Port protocol 
    hosts:								# Allowed hosts , It can also be a single domain name 
    - "*"

3.VirtualService Virtual service resources

3.1.VirtualService The concept of resources

VirtualService Resources are mainly used to define the routing rules of traffic , The traffic is forwarded to the corresponding according to the satisfied conditions Pod resources ,VirtualService Need and Gateway Associated use of resources ,Gateway The resource is equivalent to configuring the listening port , Be similar to Nginx Medium Server Configuration block , and VirtualService It is mainly used to forward traffic requests to service providers Service Resources , amount to Nginx Medium Location Configuration block ,VirtualService The resource will configure the forwarding information in Istio Of IngressGateway in .

Traffic requests will arrive first IngressGateway, configurable VirtualService Forwarding rules , Forward the request to the service provider Service Resources .

VirtualService Resources can be configured DestinationRule Resources do some flow control 、 Grayscale publishing and other functions .

VirtualService Resources are Istio Very important resources in , Just deploy the application in the grid , Will create VirtualService resources .

3.2.VirtualService Resource list file

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService			# The controller type is VirtualService
metadata:
 name: httpbin					# Controller name 
spec:
 hosts:						# Define host information , It can be a domain name 
 - "*"
 gateways:						# Associated corresponding gateways resources 
 - httpbin-gateway
 http:							# Definition http Traffic routing ordered list rule 
 - route:						# The default rules , You can redirect or forward traffic 
   - destination:				 # Define rules for traffic forwarding 
       host: httpbin			 # there host Is to forward traffic to Service resources , Fill in Service The name of the resource 
       port:					# Fill in Service The port of the resource 
         number: 8000

4.DestinationRule Target rule resource

4.1.DestinationRule The concept of resources

DestinationRule The functions of resources are very rich , It mainly deals with the traffic and defines the routing address of the virtual service , Can cooperate with VirtualService Resources realize the forwarding control of traffic 、 Grayscale publishing and so on , Depending on the supported policy , The application's Pod Resources are grouped , Forward different traffic to different Pod Resource group , To achieve the gray release of the program .

DestinationRule Support multiple load balancing strategies ： Random 、 The weight 、 Minimum requests, etc .

4.2.DestinationRule Resource list file

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule			# Define the type of resource as DestinationRule
metadata:
  name: reviews					# Define the name of the resource 
spec:
  host: reviews
  trafficPolicy:
    tls:
      mode: istio_MUTUAL
  subsets:						# Define subsets, that is, various routing rules 
  - name: v1					# Rule name 
    labels:						#Pod label 
      version: v1
  - name: v2
    labels:
      version: v2
  - name: v3
    labels:
      version: v3

5.ServiceEntry Service portal resources

ServiceEntry The main function of resources is to make Istio Applications in the grid connect to applications outside the cluster ,ServiceEntry The configuration information of will be saved in EngressGateway in .