K8S中ingress-nginx通过header路由到不同后端
公司使用ingress-nginx作为网关的项目，需要在相同域名、uri，根据header将请求转发到不同的后端中 在稳定发布的情况下，ingress-nginx是没有语法直接支持根据header做转发的。但是这个可以利用灰度发布的特性实现header路由功能 package mainimport "github.com/gin-gonic/gin" func main ( ) { r := gin. Default ( ) r. GET ( "/app" , func ( context * gin. Context) { context. JSON ( 200 , gin. H{ "message" : "app1" } ) } ) r. Run ( ":8080" )
}
使用Dockerfile构建镜像 这里构建 goapp1:v1，goapp2:v1两个镜像（goapp2请将main.go修改 “message”: “app2”） FROM golang:1.17.13
RUN mkdir -p /go/app/; \cd /go/app/; \go mod init app1;\GOPROXY="https://goproxy.cn,direct" go get github.com/gin-gonic/gin@v1.6.3
WORKDIR /go/app/
COPY main.go /go/app
EXPOSE 8080
CMD go run main.go
使用灰度发布的特性进行header的路由
此解决方案参考：https://v2-1.docs.kubesphere.io/docs/zh-CN/quick-start/ingress-canary/ 注：本人使用低版本ingress-nginx，高版本的请大家自行修改不同之处 首先部署goapp1:v1 和 goapp2:v1 的deployment和service apiVersion : apps/v1
kind : Deployment
metadata : name : goapp1namespace : default
spec : replicas : 1 selector : matchLabels : app : goapp1template : metadata : labels : app : goapp1spec : containers : - image : goapp1: v1imagePullPolicy : IfNotPresentname : goapp1ports : - containerPort : 80 protocol : TCP
---
apiVersion : v1
kind : Service
metadata : name : goapp1namespace : default
spec : ports : - port : 8080 protocol : TCPtargetPort : 8080 selector : app : goapp1
部署稳定发布版本的ingress，路由至goapp1 apiVersion : networking.k8s.io/v1
kind : Ingress
metadata : name : goapp1 namespace : defaultannotations : kubernetes.io/ingress.class : nginx
spec : rules : - host : test.comhttp : paths : - path : /app pathType : Prefixbackend : service : name : goapp1port : number : 8080 部署canary版本的ingress，路由至goapp2 这里可见 域名都是 test.com，uri都是 /app 注解： nginx.ingress.kubernetes.io/canary: “true” # 启用canary灰度发布特性 nginx.ingress.kubernetes.io/canary-by-header: canary # 通过header可选择是否转发至canary版本的后端 apiVersion : networking.k8s.io/v1
kind : Ingress
metadata : name : goapp2namespace : defaultannotations : kubernetes.io/ingress.class : nginxnginx.ingress.kubernetes.io/canary : "true" nginx.ingress.kubernetes.io/canary-by-header : canary
spec : rules : - host : test.comhttp : paths : - path : /app pathType : Prefixbackend : service : name : goapp2port : number : 8080
for i in { 1 .. 20 } ; do curl test.com:31132/app -H "canary: never" ; echo -e "" ;
done
for i in { 1 .. 20 } ; do curl test.com:31132/app -H "canary: always" ; echo -e "" ;
done
效果如下，可以看到可以通过header控制发送请求到不同后端，能够满足需求 第二种方法可通过在k8s集群部署一个nginx， 通过nginx进行分流 流量路径如下： ingress-nginx --> nginx --> goapp1或goapp2 这里nginx写法有比较多，我选择最简单的通过if判断$http_my_header 在使用$http_my_header之前，需要对ingress-nginx和nginx添加参数，允许header中存在下划线 kubectl edit cm ingress-nginx-controller
------------------
apiVersion: v1
data:allow-snippet-annotations: "true" enable-underscores-in-headers: "true" ignore-invalid-headers: "false"
kind: ConfigMap
部署nginx，nginx中开启允许header下划线的参数：underscores_in_headers on; apiVersion : apps/v1
kind : Deployment
metadata : name : nginxnamespace : default
spec : replicas : 1 selector : matchLabels : app : nginxtemplate : metadata : labels : app : nginxspec : containers : - name : nginximage : nginx: 1.24.0ports : - containerPort : 80 volumeMounts : - name : nginxmountPath : /etc/nginx/nginx.confsubPath : nginx.confvolumes : - name : nginxconfigMap : name : nginxitems : - key : nginx.confpath : nginx.conf
---
apiVersion : v1
kind : Service
metadata : name : nginxnamespace : default
spec : selector : app : nginxports : - protocol : TCPport : 80 targetPort : 80
---
apiVersion : v1
data : nginx.conf : | user nginx;worker_processes auto; error_log /var/log/nginx/error.log notice;pid /var/run/nginx.pid;events { worker_connections 1024;} http { upstream upstream_server1 { server goapp1: 8080;} upstream upstream_server2 { server goapp2: 8080;} include /etc/nginx/mime.types;default_type application/octet- stream;log_format main '$remote_addr - $remote_user [ $time_local] "$request" ''$status $body_bytes_sent "$http_referer" ''"$http_user_agent" "$http_x_forwarded_for" "$http_my_header"';access_log /var/log/nginx/access.log main;sendfile on;keepalive_timeout 65;server { underscores_in_headers on; listen 80;server_name test.com;location /app { if ($http_my_header = "value1") { proxy_pass http: //upstream_server1;} if ($http_my_header = "value2") { proxy_pass http: //upstream_server2;} } } } kind : ConfigMap
metadata : name : nginxnamespace : default
上面的配置判断 $http_my_header是 value1 还是 value2，再转发到不同的upstream 测试 curl test.com/app -H "my_header:value1"
curl test.com/app -H "my_header:value2"
