192.168.25.100 vip 虚拟ip
192.168.25.134 (nginx+keepalived）主
192.168.25.135（nginx+keepalived）备
134、135两台服务器nginx配置
server {
listen 80;
server_name localhost;
location /{
root html;
index index.html index.htm;
}
}
分别为134和135两台服务器安装keepalived，安装步骤见 Keepalived安装部署
配置192.168.25.134（主） Keepalived
进入keepalived核心配置文件所在位置
cd /etc/keepalived
vim keepalived.conf
global_defs {
router_id keep_134
}
vrrp_instance VI_1 {
# 表示状态是MASTER主机还是备用机BACKUP
state MASTER
# 该实例绑定的网卡
interface ens33
# 保证主备节点一致即可
virtual_router_id 51
# 权重，master权重一般高于backup，如果有多个，那就是选举，谁的权重高，谁就当选
priority 100
# 主备之间同步检查时间间隔，单位秒
advert_int 2
# 认证权限密码，防止非法节点进入
authentication {
auth_type PASS
auth_pass 1111
}
# 虚拟出来的ip，可以有多个（vip）
virtual_ipaddress {
192.168.25.100
}
}
配置interface绑定网卡时可以通过ip addr 查看网卡名称
[root@localhost sbin]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:34:0a:45 brd ff:ff:ff:ff:ff:ff
inet 192.168.25.134/24 brd 192.168.25.255 scope global noprefixroute dynamic ens33
valid_lft 1572sec preferred_lft 1572sec
inet6 fe80::8693:c0a4:8360:c07f/64 scope link noprefixroute
valid_lft forever preferred_lft forever
启动keepalived
cd /usr/local/keepalived/sbin
./keepalived
查看vip 在网卡ens33下，多了一个192.168.25.100，这个就是虚拟ip
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:34:0a:45 brd ff:ff:ff:ff:ff:ff
inet 192.168.25.134/24 brd 192.168.25.255 scope global noprefixroute dynamic ens33
valid_lft 1644sec preferred_lft 1644sec
inet 192.168.25.100/32 scope global ens33
valid_lft forever preferred_lft forever
inet6 fe80::8693:c0a4:8360:c07f/64 scope link noprefixroute
valid_lft forever preferred_lft forever
访问虚拟ip192.168.25.100，会跳到134这台nginx上
在这里插入图片描述
配置192.168.25.135（备
global_defs {
router_id keep_135
}
vrrp_instance VI_1 {
# 备用机设置为BACKUP
state BACKUP
interface ens33
virtual_router_id 51
# 权重低于MASTER
priority 80
advert_int 2
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
# 注意：主备两台的vip都是一样的，绑定到同一个vip
192.168.25.100
}
}
查看135的ip addr 发现是正常的 ens下只有192.168.25.135这一个IP
[root@localhost sbin]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:74:a0:91 brd ff:ff:ff:ff:ff:ff
inet 192.168.25.135/24 brd 192.168.25.255 scope global noprefixroute dynamic ens33
valid_lft 1424sec preferred_lft 1424sec
inet6 fe80::b4c1:b3db:5c81:2e92/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
link/ether 02:42:71:96:f7:b8 brd ff:ff:ff:ff:ff:ff
inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
valid_lft forever preferred_lft forever
inet6 fe80::42:71ff:fe96:f7b8/64 scope link
valid_lft forever preferred_lft forever
5: veth49aea05@if4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default
link/ether f6:14:c1:e5:c5:d2 brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet6 fe80::f414:c1ff:fee5:c5d2/64 scope link
valid_lft forever preferred_lft forever
现在需要模拟134这台机器的keepalive宕机，ps -ef | grep keepalived 查看进程号，再kill -9 进程号 这时再访问192.168.25.100时，访问会落到192.168.25.135备用机上
在这里插入图片描述
这时再查看135上的ip addr，ens33下包含192.168.25.135和虚拟ip 192.168.25.100
[root@localhost etc]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:74:a0:91 brd ff:ff:ff:ff:ff:ff
inet 192.168.25.135/24 brd 192.168.25.255 scope global noprefixroute dynamic ens33
valid_lft 1375sec preferred_lft 1375sec
inet 192.168.25.100/32 scope global ens33
valid_lft forever preferred_lft forever
inet6 fe80::b4c1:b3db:5c81:2e92/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
link/ether 02:42:71:96:f7:b8 brd ff:ff:ff:ff:ff:ff
inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
valid_lft forever preferred_lft forever
inet6 fe80::42:71ff:fe96:f7b8/64 scope link
valid_lft forever preferred_lft forever
5: veth49aea05@if4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default
link/ether f6:14:c1:e5:c5:d2 brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet6 fe80::f414:c1ff:fee5:c5d2/64 scope link
valid_lft forever preferred_lft forever
这样就实现了双机主备，但实际开发中，很少使用这种方式来搭建集群，虚拟ip也需要购买，可以构建nginx集群外加负载均衡器即可
