线上nginx的一次“no live upstreams while connecting to upstream ”分析-飞翔的单车-51CTO博客 https://blog.51cto.com/xiaosu/1689992
记一次生产环境Nginx间歇性502的事故分析过程 | XieZefan's Blog https://xiezefan.me/2017/09/27/nginx-502-bug-trace/
解决TIME_WAIT过多造成的问题 - 大东东东 - 博客园 https://www.cnblogs.com/dadonggg/p/8778318.html
netstat -n | awk '/^tcp/ {++state[$NF]} END {for(key in state) print key,"\t",state[key]}'