我已经在另外两台真实服务器上使用 ldirectord 设置了负载平衡器，以及由它管理的主动-被动 mysql 服务。
LVS 以直接路由模式运行，因此客户端请求被直接路由到当前活动的真实服务器。
真实服务器ip：192.168.3.41
虚拟ip：192.168.3.100
客户端ip（我的工作站）：192.168.100.117
我还在我们的本地办公室网关和负载均衡器之间建立了一个 OpenVPN PtP 隧道，以便远程管理主机。
负载均衡器 VPN IP：172.16.3.1
客户端 VPN 端点 IP：172.16.3.2
这就是问题所在：如果我尝试使用真实 ip 连接到 mysql，一切正常，但我需要能够使用虚拟 ip 进行连接，但这样做不行。
进行了一些网络故障排除，似乎在调用虚拟 IP 时，返回的数据包没有被路由到 VPN 隧道中，真实服务器正确回复，但当返回负载均衡器时数据包流停止。
在客户端上启动 NetCat 监听任意端口，并尝试使用其真实 IP 作为源 IP 从真实服务器进行连接，但不能使用虚拟 IP 作为源。
此外，如果我尝试使用相同的虚拟 IP 连接到在负载均衡器本身上运行的服务（端口 80 上的 lighttpd），它就可以工作了！
出于这个原因，我怀疑与 ldirectord 有关的事情，但我无法弄清楚是什么！
总结一下：
客户端在端口 3306 上调用 192.168.3.41：工作正常。
客户端在端口 80 上调用 192.168.3.100（负载均衡器上的本地 lighttpd）：工作正常。
客户端在端口 3306 上调用 192.168.3.100：不工作，数据包从真实服务器返回到负载均衡器，未被路由到 vpn。
这些是我的负载均衡器配置：
前向链：
Chain FORWARD (policy DROP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
95M 68G ACCEPT all -- * * 192.168.3.0/24 0.0.0.0/0
58M 8719M ACCEPT all -- tun+ * 0.0.0.0/0 0.0.0.0/0
17M 16G ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0
后路由链：
Chain POSTROUTING (policy ACCEPT 1377K packets, 84M bytes)
pkts bytes target prot opt in out source destination
862K 51M MASQUERADE all -- * * 192.168.3.0/24 0.0.0.0/0
101K 6159K MASQUERADE all -- * bond1 172.16.3.0/24 0.0.0.0/0
BOND 1 接口：
# ifconfig bond1
bond1 Link encap:Ethernet HWaddr 00:22:19:d5:6d:da
inet addr:192.168.3.11 Bcast:192.168.3.255 Mask:255.255.255.0
UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1
RX packets:28854406358 errors:0 dropped:356 overruns:0 frame:0
TX packets:27339806726 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:11071114840327 (10.0 TiB) TX bytes:6071397046829 (5.5 TiB)
TUN 0 接口：
# ifconfig tun0
tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
inet addr:172.16.3.1 P-t-P:172.16.3.2 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:6047779884 errors:0 dropped:0 overruns:0 frame:0
TX packets:7219390246 errors:0 dropped:3234101 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:1060763811007 (987.9 GiB) TX bytes:5651690621029 (5.1 TiB)
路由表：
# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
172.16.3.2 0.0.0.0 255.255.255.255 UH 0 0 0 tun0
192.168.100.0 172.16.3.2 255.255.255.0 UG 0 0 0 tun0
192.168.3.0 0.0.0.0 255.255.255.0 U 0 0 0 bond1
172.16.3.0 172.16.3.2 255.255.255.0 UG 0 0 0 tun0
0.0.0.0 xxx.xxx.xxx.xxx 0.0.0.0 UG 0 0 0 bond0
内核参数：
# sysctl -a|grep forw
net.ipv4.conf.all.forwarding = 1
net.ipv4.conf.all.mc_forwarding = 0
net.ipv4.conf.default.forwarding = 1
net.ipv4.conf.default.mc_forwarding = 0
net.ipv4.conf.lo.forwarding = 1
net.ipv4.conf.lo.mc_forwarding = 0
net.ipv4.conf.eth0.forwarding = 1
net.ipv4.conf.eth0.mc_forwarding = 0
net.ipv4.conf.eth1.forwarding = 1
net.ipv4.conf.eth1.mc_forwarding = 0
net.ipv4.conf.eth2.forwarding = 1
net.ipv4.conf.eth2.mc_forwarding = 0
net.ipv4.conf.eth3.forwarding = 1
net.ipv4.conf.eth3.mc_forwarding = 0
net.ipv4.conf.bond0.forwarding = 1
net.ipv4.conf.bond0.mc_forwarding = 0
net.ipv4.conf.bond1.forwarding = 1
net.ipv4.conf.bond1.mc_forwarding = 0
net.ipv4.conf.bond2.forwarding = 1
net.ipv4.conf.bond2.mc_forwarding = 0
net.ipv4.conf.tun0.forwarding = 1
net.ipv4.conf.tun0.mc_forwarding = 0
net.ipv4.ip_forward = 1
# sysctl -a|grep arp
net.ipv4.conf.all.proxy_arp = 0
net.ipv4.conf.all.arp_filter = 0
net.ipv4.conf.all.arp_announce = 0
net.ipv4.conf.all.arp_ignore = 0
net.ipv4.conf.all.arp_accept = 0
net.ipv4.conf.default.proxy_arp = 0
net.ipv4.conf.default.arp_filter = 0
net.ipv4.conf.default.arp_announce = 0
net.ipv4.conf.default.arp_ignore = 0
net.ipv4.conf.default.arp_accept = 0
net.ipv4.conf.lo.proxy_arp = 0
net.ipv4.conf.lo.arp_filter = 0
net.ipv4.conf.lo.arp_announce = 0
net.ipv4.conf.lo.arp_ignore = 0
net.ipv4.conf.lo.arp_accept = 0
net.ipv4.conf.eth0.proxy_arp = 0
net.ipv4.conf.eth0.arp_filter = 0
net.ipv4.conf.eth0.arp_announce = 0
net.ipv4.conf.eth0.arp_ignore = 0
net.ipv4.conf.eth0.arp_accept = 0
net.ipv4.conf.eth1.proxy_arp = 0
net.ipv4.conf.eth1.arp_filter = 0
net.ipv4.conf.eth1.arp_announce = 0
net.ipv4.conf.eth1.arp_ignore = 0
net.ipv4.conf.eth1.arp_accept = 0
net.ipv4.conf.eth2.proxy_arp = 0
net.ipv4.conf.eth2.arp_filter = 0
net.ipv4.conf.eth2.arp_announce = 0
net.ipv4.conf.eth2.arp_ignore = 0
net.ipv4.conf.eth2.arp_accept = 0
net.ipv4.conf.eth3.proxy_arp = 0
net.ipv4.conf.eth3.arp_filter = 0
net.ipv4.conf.eth3.arp_announce = 0
net.ipv4.conf.eth3.arp_ignore = 0
net.ipv4.conf.eth3.arp_accept = 0
net.ipv4.conf.bond0.proxy_arp = 0
net.ipv4.conf.bond0.arp_filter = 0
net.ipv4.conf.bond0.arp_announce = 0
net.ipv4.conf.bond0.arp_ignore = 0
net.ipv4.conf.bond0.arp_accept = 0
net.ipv4.conf.bond1.proxy_arp = 0
net.ipv4.conf.bond1.arp_filter = 0
net.ipv4.conf.bond1.arp_announce = 0
net.ipv4.conf.bond1.arp_ignore = 0
net.ipv4.conf.bond1.arp_accept = 0
net.ipv4.conf.bond2.proxy_arp = 0
net.ipv4.conf.bond2.arp_filter = 0
net.ipv4.conf.bond2.arp_announce = 0
net.ipv4.conf.bond2.arp_ignore = 0
net.ipv4.conf.bond2.arp_accept = 0
net.ipv4.conf.tun0.proxy_arp = 0
net.ipv4.conf.tun0.arp_filter = 0
net.ipv4.conf.tun0.arp_announce = 0
net.ipv4.conf.tun0.arp_ignore = 0
net.ipv4.conf.tun0.arp_accept = 0
提前感谢你的帮助。