Keepalived 安装配置详解
Keepalived 是一个基于 Linux 平台的高可用性解决方案，可以实现服务器的负载均衡和高可用性。下面是 Keepalived 的安装配置详解。
一、安装 Keepalived
Keepalived 可以通过 yum 安装或源码编译安装。yum 安装命令为：
```
yum install keepalived
```
源码编译安装需要先安装依赖软件包，然后下载 Keepalived 的源码，编译安装。命令为：
```
yum install -y openssl-devel libnl libnl-devel libnfnetlink-devel
wget http://www.keepalived.org/software/keepalived-1.2.13.tar.gz
tar -zvxf keepalived-1.2.13.tar.gz
cd keepalived-1.2.13
./configure --prefix=/usr/local/keepalived
make && make install
```
在安装完成后，需要将 Keepalived 的配置文件和启动脚本复制到相应的目录中：
```
cp /root/keepalived-1.2.13/keepalived/etc/init.d/keepalived.init /etc/rc.d/init.d/keepalived
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
mkdir /etc/keepalived/
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
echo "/etc/init.d/keepalived start" >> /etc/rc.local
```
二、配置 Keepalived
Keepalived 的配置文件为 `/etc/keepalived/keepalived.conf`，其中包含了全局定义、VRRP 实例和脚本检查等信息。配置文件的格式为：
```
global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_haproxy {
script "killall -0 haproxy"
interval 1
weight -10
rise 1
fall 2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_haproxy
}
virtual_ipaddress {
192.168.13.200
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
```
在配置文件中，我们定义了一个 VRRP 实例 VI_1，它的状态为 MASTER，接口为 eth0，虚拟路由器 ID 为 51，优先级为 100 IOCTL 时间间隔为 1 秒。我们还定义了一个脚本检查 chk_haproxy，它每秒钟检查一次 Haproxy 的状态。
三、启动 Keepalived
在配置完成后，我们需要启动 Keepalived 服务：
```
chmod +x /etc/rc.d/init.d/keepalived
chkconfig keepalived on
service keepalived start
```
四、常见问题
在使用 Keepalived 时，可能会遇到一些常见的问题，例如无法启动 Keepalived 服务、无法连接虚拟 IP 等。这些问题通常是由于配置文件错误或网络连接问题引起的。
Keepalived 是一个功能强大且灵活的高可用性解决方案，通过正确的安装和配置，可以实现服务器的负载均衡和高可用性。
