[LVS] 用keepalived实现LVS NAT模式高可用性
默认前提是LVS已经可以正常工作了。
因为是NAT模式，RS的路由要指向LVS的接口地址，所以需要一个统一的后台浮动地址，使得RS都指向这个浮动IP.
否则在切换时，会导致RS回包到DOWN掉的LVS上，使得请求超时失败。
1. 下载相关软件包
#wget http://www.keepalived.org/software/keepalived-1.1.15.tar.gz
2. 安装Keepalived
#tar zxvf keepalived-1.1.15.tar.gz
#cd keepalived-1.1.15
#./configure --with-kernel-dir=/kernel/path&& make && make install
#find / -name keepalived# 查看keepalived位置
#cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
#cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
#mkdir /etc/keepalived
#cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/
#cp /usr/local/sbin/keepalived /usr/sbin/
#service keepalived start|stop #做成系统启动服务方便管理.
如果自己手工编译keepalived的话最好加上--with-kernel-dir=/kernel/path参数，如果keepalived找不到内核源码，在编译时会不编译lvs支持。
仔细看./configure 最后的提示：
找不到内核源码提示如下：
Keepalived configuration
------------------------
Keepalived version : 1.1.15
Compiler : gcc
Compiler flags : -g -O2
Extra Lib : -lpopt -lssl -lcrypto
Use IPVS Framework : No
IPVS sync daemon support : No
Use VRRP Framework : Yes
Use LinkWatch : No
Use Debug flags : No
找到内核源码提示如下：
Keepalived configuration
------------------------
Keepalived version : 1.1.15
Compiler : gcc
Compiler flags : -g -O2
Extra Lib : -lpopt -lssl -lcrypto
Use IPVS Framework : Yes
IPVS sync daemon support : Yes
Use VRRP Framework : Yes
Use LinkWatch : No
Use Debug flags : No
3. 再两台LVS上配置keepalived.conf:
# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state MASTER #备份服务器上将MASTER改为BACKUP
interface eth11
virtual_router_id 51
priority 100 # 备份服务上将100改为99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
11.11.11.15
}
}
vrrp_instance VI_2 {
state MASTER
interface eth12
virtual_router_id 50
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
22.22.22.2
}
}
virtual_server 11.11.11.15 80 {
delay_loop 6 #(每隔10秒查询realserver状态)
lb_algo rr #(lvs 算法)
lb_kind NAT
nat_mask 255.255.255.0
persistence_timeout 50 #(同一IP的连接60秒内被分配到同一台realserver)
protocol TCP #(用TCP协议检查realserver状态)
real_server 22.22.22.23 80 {
weight 1 #(权重)
TCP_CHECK {
connect_timeout 3 #(3秒无响应超时)
nb_get_retry 3
delay_before_retry 3
}
}
real_server 22.22.22.24 80 {
weight 1
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
4. 查看lvs服务是否正常
a) 首先在两台LVS上开启keepalived，执行 "ip addr", 观察Master上的浮动IP是否存在。
b) 关闭Master的keepalived 服务，在BACKUP上执行“ip addr”，观察浮动IP是否切换过来了。
c) 从Client端，访问LVS vIP,切换两台LVS的主备状态，观察请求是否可以切换。
5. 拓扑：
外网 外网浮动VIP 内网 内网浮动IP
Client 11.11.11.11
LVS1 11.11.11.12 11.11.11.15 22.22.22.22 22.22.22.2
LVS1 11.11.11.13 22.22.22.25
Server1 22.22.22.23
Server2 22.22.22.24
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