Centos haproxy获得的502错误太多

我的haproxy日志中出现了很多

“状态”：“502”

错误，同时使用相同的url请求很好，状态为“200”

有线的事情是请求时间为零，似乎永远不要尝试建立连接

{“时间戳”：“2021-05-27T13:28:13+08:00”，“远程地址”： “101.200.28.###”、“请求uri”： “/pinsurvey/api/v1/projects/”，“协议”：“HTTP/1.1”，“请求方法”： “获取”、“发送状态”：“502”、“正文字节”： “568”、“http_x_forwarded_”：“112.103.45.###”、“http_referer”： "https://servicewechat.com/wx0aa7dbf32636dc01/42/page-frame.html“，“请求时间”： “0.000”，“上游响应时间”：“0.000: 0.000“，“上游地址”：“本地主机：本地主机”，“上游连接时间”：“0.000: 0.000“，“http_user_agent”：“Mozilla/5.0（Linux；Android 10；HRY-AL00Ta构建/HONORHRY-AL00Ta；wv）AppleWebKit/537.36（KHTML，类似 Gecko）版本/4.0 Chrome/78.0.3904.62 XWEB/2797 MMWEBDK/20210302 Mobile Safari/537.36 MMWEBID/7133 微传感器/8.0.3.1880（0x2800033D）过程/appbrand0微信/arm64 微信NetType/WIFI语言/zh_CN ABI/arm64微程序环境/android“}

这是我的haproxy.cfg文件：

global
    log         /dev/log local0

    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     30000
    user        haproxy
    group       haproxy
    daemon

    stats socket /var/lib/haproxy/stats


defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000

listen stats                      
    mode  http
    bind  *:7992
    stats refresh 30s
    stats uri /stats              
    stats realm HAProxy Stats

#---------------------------------------------------------------------
# main frontend which proxys to the backends
#---------------------------------------------------------------------
frontend  main
    bind  *:7879
    # ez-admin-api
    acl ez_admin_acl path_beg -i /ez-admin/
    use_backend ez_admin if ez_admin_acl

    # pinsurvey-api
    acl pinsurvey_acl path_beg -i /pinsurvey/
    use_backend pinsurvey if pinsurvey_acl

    # ez-datamanagement-api
    acl ez_datamanagement_acl path_beg -i /ez-datamanagement/
    use_backend ez_datamanagement if ez_datamanagement_acl

    default_backend             ez_admin

backend ez_admin
    http-request replace-path /ez-admin/(.*) /\1
    balance  roundrobin
    server   ez_admin_22 127.0.0.1:7807 check
    server   ez_admin_142 172.17.28.73:7807 check

backend pinsurvey
    http-request replace-path /pinsurvey/(.*) /\1
    balance  roundrobin
    server   pinsurvey_159 172.17.28.66:7878 check
    server   pinsurvey_52 172.17.28.52:7878 check
    server   pinsurvey_124 123.56.241.124:7878 check
    server   pinsurvey_30 182.92.201.30:7878 check
    server   pinsurvey_34 172.17.117.34:7878 check

backend ez_datamanagement
    http-request replace-path /ez-datamanagement/(.*) /\1
    balance  roundrobin
    server   ez_datamanagement_1 192.168.10.219:7801 check