我正在学习在单台机器上使用 keepalived；只是为了确保转发正常。
我已经启动了一个模拟网络服务器，监听 192.168.56.200:8080。它只回复主机名。
$ curl http://192.168.56.200:8080/
controller-1
现在我已经配置了keepalived（/etc/keepalived/keepalived.conf）：
virtual_server 192.168.111.1 8082 {
delay_loop 30
lb_algo rr
lb_kind DR
persistence_timeout 50
protocol TCP
real_server 192.168.56.200 8080 {
weight 1
TCP_CHECK {
}
}
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 1
priority 100
virtual_ipaddress {
192.168.111.1/24
}
}
但它似乎不起作用：
$ curl http://192.168.111.1:8082/
curl: (7) couldn't connect to host
$ telnet 192.168.111.1 8082
Trying 192.168.111.1...
telnet: Unable to connect to remote host: Connection refused
确实，根据 netstat -apn | grep 8082 显示，没有人在监听端口 8082，不过 keepalived 可能应该监听。
我的配置有什么问题？
更多有用的信息：
$ ip a
...
2: eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 08:00:27:4e:4b:c6 brd ff:ff:ff:ff:ff:ff
inet 192.168.111.1/24 scope global eth0
inet6 fe80::a00:27ff:fe4e:4bc6/64 scope link
valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
link/ether 08:00:27:9d:c4:b0 brd ff:ff:ff:ff:ff:ff
inet 192.168.56.200/24 scope global eth1
inet6 fe80::a00:27ff:fe9d:c4b0/64 scope link
valid_lft forever preferred_lft forever
和系统日志：
Aug 10 22:58:36 controller-1 Keepalived: Starting Keepalived v1.2.2 (12/23,2011)
Aug 10 22:58:36 controller-1 Keepalived: Starting Healthcheck child process, pid=5257
Aug 10 22:58:36 controller-1 Keepalived: Starting VRRP child process, pid=5258
Aug 10 22:58:36 controller-1 Keepalived_healthcheckers: Initializing ipvs 2.6
Aug 10 22:58:36 controller-1 Keepalived_healthcheckers: Registering Kernel netlink reflector
Aug 10 22:58:36 controller-1 Keepalived_healthcheckers: Registering Kernel netlink command channel
Aug 10 22:58:36 controller-1 Keepalived_healthcheckers: Opening file '/etc/keepalived/keepalived.conf'.
Aug 10 22:58:36 controller-1 Keepalived_healthcheckers: Configuration is using : 8775 Bytes
Aug 10 22:58:36 controller-1 Keepalived_vrrp: Registering Kernel netlink reflector
Aug 10 22:58:36 controller-1 Keepalived_vrrp: Registering Kernel netlink command channel
Aug 10 22:58:36 controller-1 Keepalived_vrrp: Registering gratutious ARP shared channel
Aug 10 22:58:36 controller-1 Keepalived_vrrp: Initializing ipvs 2.6
Aug 10 22:58:36 controller-1 Keepalived_vrrp: Opening file '/etc/keepalived/keepalived.conf'.
Aug 10 22:58:36 controller-1 Keepalived_vrrp: Configuration is using : 59356 Bytes
Aug 10 22:58:36 controller-1 Keepalived_vrrp: Using LinkWatch kernel netlink reflector...
Aug 10 22:58:36 controller-1 Keepalived_healthcheckers: Using LinkWatch kernel netlink reflector...
Aug 10 22:58:36 controller-1 Keepalived_healthcheckers: Activating healtchecker for service [192.168.56.200]:8080
Aug 10 22:58:37 controller-1 ntpd[1318]: Deleting interface #22 eth0, 192.168.111.1#123, interface stats: received=0, sent=0, dropped=0, active_time=76 secs
Aug 10 22:58:37 controller-1 ntpd[1318]: peers refreshed
Aug 10 22:58:37 controller-1 Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE
Aug 10 22:58:38 controller-1 Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE
Aug 10 22:58:38 controller-1 avahi-daemon[775]: Joining mDNS multicast group on interface eth0.IPv4 with address 192.168.111.1.
Aug 10 22:58:38 controller-1 avahi-daemon[775]: New relevant interface eth0.IPv4 for mDNS.
Aug 10 22:58:38 controller-1 avahi-daemon[775]: Registering new address record for 192.168.111.1 on eth0.IPv4.
Aug 10 22:58:40 controller-1 ntpd[1318]: Listen normally on 23 eth0 192.168.111.1 UDP 123
Aug 10 22:58:40 controller-1 ntpd[1318]: peers refreshed
Aug 10 22:58:40 controller-1 ntpd[1318]: new interface(s) found: waking up resolver
Aug 10 22:58:42 controller-1 ntpd_intres[1320]: host name not found: 0.ubuntu.pool.ntp.org
Aug 10 22:58:42 controller-1 ntpd_intres[1320]: host name not found: 1.ubuntu.pool.ntp.org
Aug 10 22:58:42 controller-1 ntpd_intres[1320]: host name not found: 2.ubuntu.pool.ntp.org
Aug 10 22:58:42 controller-1 ntpd_intres[1320]: host name not found: 3.ubuntu.pool.ntp.org
Aug 10 22:58:42 controller-1 ntpd_intres[1320]: host name not found: ntp.ubuntu.com
在 sysctl 中，ip_forward 和 ip_nonlocal_bind 已启用。
答案1
您的服务器应用程序需要监听0.0.0.0:8080，而不仅仅是监听192.168.56.200:8080。
使用它来验证服务器正在监听的位置：
netstat -nlta | grep 8080
您可能会发现这一点：
tcp 0 0 192.168.56.200:8080 0.0.0.0:* LISTEN
这表示服务明确侦听该地址，而不是系统上可能配置的任何其他地址。您还可以使用指令在notify_状态更改时发出活动信号（例如，重新启动服务，以便它知道新的 IP 地址）。
notify_master "/etc/init.d/service start"
notify_backup "/etc/init.d/service stop"
notify_fault "/etc/init.d/service stop"