使用 keepalived 设置虚拟 IP 环境

原文地址：https://blog.csdn.net/kongxx/article/details/73173762

使用 keepalived 设置虚拟 IP 环境
准备
准备两个机器，IP地址信息如下：

host1： 192.168.56.103
host2： 192.168.56.104
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为了测试需要，分别在两个机器上安装apache并启动httpd服务，使下面两个url均可访问
- http://192.168.56.103
- http://192.168.56.104

安装 keepalived
在两台机器上分别安装 keepalived

$ sudo yum install -y keepalived
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配置 keepalived
host1 上 keepalived 配置
$ cat /etc/keepalived/keepalived.conf
vrrp_instance VI_1 {
state MASTER
interface eth2
virtual_router_id 51
priority 101
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.56.105
}
}
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host2 上 keepalived 配置
$ cat /etc/keepalived/keepalived.conf
vrrp_instance VI_1 {
state MASTER
interface eth2
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.56.105
}
}
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启动 keepalived 服务
$ sudo service keepalived start
$ sudo chkconfig keepalived on
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测试
服务启动后，先访问下面的虚拟地址访问http服务器

http://192.168.56.105
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查看IP地址信息
host1 上 IP 地址信息

$ ip addr show eth2
3: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 08:00:27:32:83:82 brd ff:ff:ff:ff:ff:ff
inet 192.168.56.103/24 brd 192.168.56.255 scope global eth2
inet 192.168.56.105/32 scope global eth2
inet6 fe80::a00:27ff:fe32:8382/64 scope link
valid_lft forever preferred_lft forever
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其中可以看到 inet 192.168.56.105/32 scope global eth2，说明现在host1是作为虚拟IP的master来运行的。
host2 上 IP 地址信息

$ ip addr show eth2
3: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 08:00:27:ec:90:7b brd ff:ff:ff:ff:ff:ff
inet 192.168.56.104/24 brd 192.168.56.255 scope global eth2
inet6 fe80::a00:27ff:feec:907b/64 scope link
valid_lft forever preferred_lft forever
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此时host2上ip地址信息中不包含虚拟IP “192.168.56.105” 信息。
验证 IP 地址 Failover
现在手动停止host1上的 keepalived 服务

$ sudo service keepalived stop
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host1 上 IP 地址信息

$ ip addr show eth2
3: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 08:00:27:32:83:82 brd ff:ff:ff:ff:ff:ff
inet 192.168.56.103/24 brd 192.168.56.255 scope global eth2
inet6 fe80::a00:27ff:fe32:8382/64 scope link
valid_lft forever preferred_lft forever
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此时 host1 上 ip 地址信息中不再包含虚拟IP “192.168.56.105” 信息。
host2 上 IP 地址信息

$ ip addr show eth2
3: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 08:00:27:ec:90:7b brd ff:ff:ff:ff:ff:ff
inet 192.168.56.104/24 brd 192.168.56.255 scope global eth2
inet 192.168.56.105/32 scope global eth2
inet6 fe80::a00:27ff:feec:907b/64 scope link
valid_lft forever preferred_lft forever
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现在可以看到 host2 上 ip 地址信息中已经包含虚拟IP “192.168.56.105” 信息了。
此时如果再把 host1 上的 keepalived 服务启动，会发现虚拟IP “192.168.56.105” 又重新绑定到 host1 上了。
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作者：kongxx
来源：CSDN
原文：https://blog.csdn.net/kongxx/article/details/73173762
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