nginx反向代理出现502错误，日志显示no live upstreams

出现oa单在签核的时候出现502错误，查看nginx错误日志出现no live upstreams while connecting to upstream

解决方案：

原upstream配置

 upstream oa{
    ip_hash;
    server   10.0.2.30:80;
    server   10.0.2.17:80;
    check interval=3000 rise=2 fall=2 timeout=1000 type=http;
}

修改后upstream配置

upstream oa{
    ip_hash;
    server   10.0.2.30:80 max_fails=3 fail_timeout=5s;
    server   10.0.2.17:80 max_fails=3 fail_timeout=5s;
    check interval=3000 rise=2 fall=2 timeout=1000 type=http;
}