Load-Balancing
HAproxy 503 Service Unavailable No server is available to handle this request
我是這種負載平衡方案的新手，我的任務是弄清楚如何使這種負載平衡起作用。
我的環境：
Centos 6.4 64 Bit Webserver: Lighttpd All running in ESXI virtual IP: 192.168.1.6 LB1: 192.168.1.4 LB2: 192.168.1.5 Webserver 1: 192.168.1.12 Webserver 2: 192.168.1.13 Gateway: 192.168.1.1嘗試在使用 HAproxy 和 keepalived 進行生產之前在實驗室中執行測試。這是我的keepalived設置：
！keepalived的配置文件
global_defs { notification_email { myemail@gmail.com } notification_email_from keepalived@domain.local smtp_server 192.168.1.4 smtp_connect_timeout 30 router_id 192.168.1.1 } vrrp_script chk_haproxy { script "killall -0 haproxy" interval 1 # check every second weight 2 # add 2 points of prio if OK } vrrp_instance VI_1 { state MASTER interface eth0 virtual_router_id 51 priority 101 #priority 101 for master advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.1.6 } track_script { chk_haproxy } }這是我對 HAproxy 的設置
#--------------------------------------------------------------------- # Example configuration for a possible web application. See the # full configuration options online. # # http://haproxy.1wt.eu/download/1.4/doc/configuration.txt # #--------------------------------------------------------------------- #--------------------------------------------------------------------- # Global settings #--------------------------------------------------------------------- global # to have these messages end up in /var/log/haproxy.log you will # need to: # # 1) configure syslog to accept network log events. This is done # by adding the '-r' option to the SYSLOGD_OPTIONS in # /etc/sysconfig/syslog # # 2) configure local2 events to go to the /var/log/haproxy.log # file. A line like the following can be added to # /etc/sysconfig/syslog # # local2.* /var/log/haproxy.log # log 127.0.0.1 local2 chroot /var/lib/haproxy pidfile /var/run/haproxy.pid maxconn 4000 user haproxy group haproxy daemon # turn on stats unix socket stats socket /var/lib/haproxy/stats #--------------------------------------------------------------------- # common defaults that all the 'listen' and 'backend' sections will # use if not designated in their block #--------------------------------------------------------------------- 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 #--------------------------------------------------------------------- # main frontend which proxys to the backends #--------------------------------------------------------------------- frontend main *:80 # acl url_static path_beg -i /static /images /javascript /stylesheets # acl url_static path_end -i .jpg .gif .png .css .js # use_backend static if url_static # default_backend view #--------------------------------------------------------------------- # static backend for serving up images, stylesheets and such #--------------------------------------------------------------------- #backend static # balance roundrobin # server static 127.0.0.1:4331 check #--------------------------------------------------------------------- # round robin balancing between the various backends #--------------------------------------------------------------------- backend app mode tcp balance roundrobin server server1 192.168.1.12:80 check inter 2000 rise 2 fall 5 server server2 192.168.1.13:80 check inter 2000 rise 2 fall 5當我啟動 HAproxy 時，我得到了這個錯誤，我不太確定從哪裡開始尋找修復它。也許做過很多次的人可以幫我解釋一下？
503 Service Unavailable No server is available to handle this request.但是手動連接到 webserver1 和 webserver2 就可以了。
我想要的只是對位於 HAproxy 後面的網路伺服器進行簡單的負載平衡。絕對感謝任何建議或建議。請幫忙？非常感謝。
我從未使用過 HAproxy，但快速搜尋讓我認為您需要
default_backend app立即在下面添加frontend main *:80。在將後端和前端連接在一起的配置中，我看不到任何地方。
問題出在您的 HAProxy 配置中。當我從您的配置中刪除所有評論時，我會得到：
global log 127.0.0.1 local2 chroot /var/lib/haproxy pidfile /var/run/haproxy.pid maxconn 4000 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 frontend main *:80 backend app mode tcp balance roundrobin server server1 192.168.1.12:80 check inter 2000 rise 2 fall 5 server server2 192.168.1.13:80 check inter 2000 rise 2 fall 5現在您可以清楚地看到根本沒有前端的配置。請求通過 HAProxy 到達，
frontend main但 HAProxy 不知道哪些伺服器可以可靠地處理它，因此將返回 503。
default_backend您必須使用或使用 acl將後端連結到前端。您也應該使用統計資訊，不僅使用套接字，還使用受保護的 Web 界面。我可以向您顯示有關 haproxy 背後的集群的資訊，哪些伺服器處於離線狀態，哪些有任何問題，關於響應時間等等。對調試非常有用。