34、k8s-service类型-第五种-ExternalName-将外部服务接入到集群内部
概念:ExternalName类型的service用于引入集群外的服务、它通过externalname属性指定外部一个服务的地址、然后在集群内部访问此service就可以访问到外部的服务了
案例
1、新建ExternalName的yaml文件:vim service-externalname.yaml
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apiVersion: v1
kind: Service
metadata:
name: service-externalname
namespace: dev
spec:
type: ExternalName
externalName: www.baidu.com
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2、创建externalname:kubectl create -f service-externalname.yaml
3、查看:kubectl get svc service-externalname -ndev
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NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service-externalname ExternalName <none> www.baidu.com <none> 46s
#其中EXTERNAL-IP 是指向外部的地址
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4、查看详情:kubectl describe svc service-externalname -ndev
5、域名解析访问:dig @10.96.0.10 service-externalname.dev.svc.cluster.local
·注意这个10.96.0.10 IP是域名解析服务通过进到pod里面获取:查看pod里面的文件:cat /etc/resolv.conf
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; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.14 <<>> @10.96.0.10 service-externalname.dev.svc.cluster.local
; (1 server found)
;; global options: +cmd
;; Got answer:
;; WARNING: .local is reserved for Multicast DNS
;; You are currently testing what happens when an mDNS query is leaked to DNS
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10492
;; flags: qr aa rd; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;service-externalname.dev.svc.cluster.local. IN A
;; ANSWER SECTION:
service-externalname.dev.svc.cluster.local. 30 IN CNAME www.baidu.com. #这里就是访问的外部地址
www.baidu.com. 30 IN CNAME www.a.shifen.com.
www.a.shifen.com. 30 IN A 14.119.104.254
www.a.shifen.com. 30 IN A 14.119.104.189
;; Query time: 35 msec
;; SERVER: 10.96.0.10#53(10.96.0.10)
;; WHEN: Mon Sep 04 23:22:33 CST 2023
;; MSG SIZE rcvd: 247
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