这篇文档只讨论keepalived的基本应用，不深入讨论结合lvs的应用
OS：centos 5.10
主机A：
eth0： 192.168.1.204
vip： 192.168.1.207
tomcat+nginx
主机B
eth0： 192.168.1.206
vip： 192.168.1.207
tomcat+nginx
实现目标：平时主机A提供服务，B待命，当A主机当机或者nginx或者tomcat故障的时候，由主机B来充当web服务。当A主机恢复的时候，B的承担服务的责任再次交还给主机A。
这个方案虽然主机B提供服务器的概率不高，但实际效果还是很有效的，也不失为一个初级的热备方案
1：首相A,B俩主机时间同步
2：安装keepalived
yum -y install gcc make openssl openssl-devel wget kernel-devel |
wget http://www.keepalived.org/software/keepalived-1.2.13.tar.gz |
编译安装
./configure --prefix=/usr/local/keepalived --with-kernel-dir=/usr/src/kernels/2.6.18-371.8.1.el5-x86_64/ --disable-lvs |
或者（1.2.13版本）
./configure --prefix=/usr/local/keepalived --with-kernel-dir=/usr/src/kernels/2.6.18-371.8.1.el5-x86_64/ --disable-fwmark --disable-lvs make make install |
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/ cp keepalived/etc/init.d/keepalived.rh.init /etc/init.d/keepalived cp keepalived/etc/init.d/keepalived.sysconfig /etc/sysconfig/keepalived |
chmod +x /etc/init.d/keepalived chkconfig --add keepalived chkconfig --level 3 keepalived on |
主机A配置：
vim /etc/keepalived/keepalived.conf |
global_defs
{
notification_email
{
username@email.com
}
notification_email_from username@email.com
smtp_server 127.0.0.1
stmp_connect_timeout 30
router_id c3_204 #这个名字根据自己需要随便取
}
vrrp_script chk_nginx {
script "killall -0 nginx" #检查nginx进程
interval 1 #检查频率 1秒
weight -2 #如果发现nginx进程不在，优先级降低2
}
vrrp_script chk_tomcat {
script "killall -0 java" #检查tomcat进程
interval 1 #检查频率 1秒
weight -2 #如果发现tomcat进程不在，优先级降低2
}
vrrp_instance shengzc {
state BACKUP
interface eth0
virtual_router_id 100 #这个ID A B主机必须保持一致
priority 151 #优先级，越大优先级越大
advert_int 1
track_interface {
eth0
}
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.1.207
#192.168.1.207 dev eth0 label eth0:1 #如果想直接通过ifconfig显示eth0:1信息，用这个语法
}
track_script {
chk_nginx
chk_tomcat
}
} |
主机B配置：
vim /etc/keepalived/keepalived.conf |
global_defs
{
notification_email
{
username@email.com
}
notification_email_from username@email.com
smtp_server 127.0.0.1
stmp_connect_timeout 30
router_id c5_206 #这个名字根据自己需要随便取
}
vrrp_script chk_nginx {
script "killall -0 nginx" #检查nginx进程
interval 1 #检查频率 1秒
weight -2 #如果发现nginx进程不在，优先级降低2
}
vrrp_script chk_tomcat {
script "killall -0 java" #检查tomcat进程
interval 1 #检查频率 1秒
weight -2 #如果发现tomcat进程不在，优先级降低2
}
vrrp_instance shengzc {
state BACKUP
interface eth0
virtual_router_id 100 #这个ID A B主机必须保持一致
priority 150 #优先级，越大优先级越大
advert_int 1
track_interface {
eth0
}
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.1.207
#192.168.1.207 dev eth0 label eth0:1 #如果想直接通过ifconfig显示eth0:1信息，用这个语法
}
track_script {
chk_nginx
chk_tomcat
}
} |
iptables设置：
vim /etc/sysconfig/iptables |
注意添加
-A RH-Firewall-1-INPUT -p vrrp -j ACCEPT |
否则会出现
May 14 11:16:37 s3 Keepalived_vrrp[7591]: VRRP_Instance(shengzc) Received lower prio advert, forcing new election
May 14 11:16:37 s3 Keepalived_vrrp[7591]: VRRP_Instance(shengzc) Sending gratuitous ARPs on eth0 for 192.168.1.207
类似这样的错误
好了，同时启动A B主机的keepalived
/etc/init.d/keepalived start |
可以测试关掉A机器的nginx进程 tomcat进程 或者断网 是否能切换到B机器那儿去