所有后端服务器都必须启动haproxy吗？

我想先从以下配置HAProxy的负载均衡器：所有后端服务器都必须启动haproxy吗？

global 
    log 127.0.0.1 local0 
    log 127.0.0.1 local0 notice 

resolvers docker 
    nameserver dnsmasq 1.2.3.4:53 

defaults 
    mode http 
    log global 
    option httplog 
    option dontlognull 

frontend ft_radix_real 
    bind *:61616 
    maxconn 6000 
    acl is_websocket hdr(Upgrade) -i WebSocket 
    acl is_websocket hdr_beg(Host) -i ws 
    use_backend bk_radix_real if is_websocket 

backend bk_radix_real 
    balance roundrobin 
    option forwardfor 
    server radix-real-1 1.2.3.4:1884 check resolvers docker resolve-prefer ipv4 
    server radix-real-2 1.2.3.4:1884 check resolvers docker resolve-prefer ipv4 
    server radix-real-3 1.2.3.4:1884 check resolvers docker resolve-prefer ipv4 
    server radix-real-4 1.2.3.4:1884 check resolvers docker resolve-prefer ipv4 

listen stats 
    mode http 
    option httplog 
    option dontlognull 
    bind *:1936 
    stats enable 
    stats scope ft_radix_real 
    stats scope bk_radix_real 
    stats uri/
    stats realm Haproxy\ Statistics 
    stats auth admin:admin

当所有后端服务器均达到这种配置工作。但是，即使某些（不是全部）后端服务器未运行，我也希望能够启动Haproxy。我检查了配置文件，但找不到解决方案。可能吗？

来源

2016-01-06 gray_malkin