[{"createTime":1735734952000,"id":1,"img":"hwy_ms_500_252.jpeg","link":"https://activity.huaweicloud.com/cps.html?fromacct=261f35b6-af54-4511-a2ca-910fa15905d1&utm_source=V1g3MDY4NTY=&utm_medium=cps&utm_campaign=201905","name":"华为云秒杀","status":9,"txt":"华为云38元秒杀","type":1,"updateTime":1735747411000,"userId":3},{"createTime":1736173885000,"id":2,"img":"txy_480_300.png","link":"https://cloud.tencent.com/act/cps/redirect?redirect=1077&cps_key=edb15096bfff75effaaa8c8bb66138bd&from=console","name":"腾讯云秒杀","status":9,"txt":"腾讯云限量秒杀","type":1,"updateTime":1736173885000,"userId":3},{"createTime":1736177492000,"id":3,"img":"aly_251_140.png","link":"https://www.aliyun.com/minisite/goods?userCode=pwp8kmv3","memo":"","name":"阿里云","status":9,"txt":"阿里云2折起","type":1,"updateTime":1736177492000,"userId":3},{"createTime":1735660800000,"id":4,"img":"vultr_560_300.png","link":"https://www.vultr.com/?ref=9603742-8H","name":"Vultr","status":9,"txt":"Vultr送$100","type":1,"updateTime":1735660800000,"userId":3},{"createTime":1735660800000,"id":5,"img":"jdy_663_320.jpg","link":"https://3.cn/2ay1-e5t","name":"京东云","status":9,"txt":"京东云特惠专区","type":1,"updateTime":1735660800000,"userId":3},{"createTime":1735660800000,"id":6,"img":"new_ads.png","link":"https://www.iodraw.com/ads","name":"发布广告","status":9,"txt":"发布广告","type":1,"updateTime":1735660800000,"userId":3},{"createTime":1735660800000,"id":7,"img":"yun_910_50.png","link":"https://activity.huaweicloud.com/discount_area_v5/index.html?fromacct=261f35b6-af54-4511-a2ca-910fa15905d1&utm_source=aXhpYW95YW5nOA===&utm_medium=cps&utm_campaign=201905","name":"底部","status":9,"txt":"高性能云服务器2折起","type":2,"updateTime":1735660800000,"userId":3}]
<>环境：
k8s+docker
<>问题描述:
由于pod生命周期问题，或程序问题引起，pod重启，或删除后重新被deployment拉起以后，pod本身ip发生改变，nginx代理到前端，或者后端的service名称无法正常解析到新的pod
ip。
<>dns解析原理
这是nginx本身域名解析存在问题，由于只有在通过nginx第一次向proxy_pass后端对应的域名做代理数据转发时，这里nginx会通过操作系统配置的DNS服务器解析域名，此时才会缓存域名对应的IP，且会缓存很长时间，甚至一个月，由此导致pod重启后，不会重新解析到新的ip而导致nginx返回504的原因
<>解析图如下：
<>变更nginx配置遇到的坑
官网文档给了一个nginx自定dns服务器的配置：
resolver kube-dns.kube-system.svc.cluster.local valid=5s;
resolver_timeout 3s;
第一行：即重新指定DNS服务器， valid控制dns缓存时间，覆盖ttl值
第二行：控制域名解析超时时间。
我将这两行配置写入配置文件后，根据解析原理来说，nginx会先找系统本身的dns服务器去做对应，解析，而
