keepalived高可用安装
1）环境准备
| 主机名 | 角色 | 外网ip |
|---|---|---|
| lb01 | keepalived-master | eth0:10.0.0.5 |
| lb01 | keepalived-slave | eth0:10.0.0.6 |
2）在lb01和lb02上分别安装keepalived
[root@lb01 ~]# yum install -y keepalived
[root@lb02 ~]# yum install -y keepalived
3）keepalived工作原理
- vrrp 虚拟路由冗余协议 诞生是为公司网站网络设备做高可用 3层路由
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4）keepalived文件详解
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配置keepalived
手动测试添加ip地址
ip addr add 10.0.0.3/24 dev eth0:1
ip addr del 10.0.0.3/24 dev eth0:1
lb01（主）配置如下
[root@lb01 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id lb01 #主备不能一样
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3/24 dev eth0 label eth0:1
#10.0.0.3/24 直接写ip，需要手动添加10.0.0.3（vip）
}
}
lb02(备)配置如下
[root@lb02 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id lb02 #主备不能一样
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3/24 dev eth0 label eth0:1
}
}
测试
lb01 lb02操作如下
1）重启keepalived
systemctl restart keepalived
- lb01检查是否有vip
[root@lb01 ~]# ip a|grep 0.3 inet 10.0.0.3/24 scope global secondary eth0:1
3）lb02检查是否有vip
[root@lb02 ~]# ip a|grep 0.3
[root@lb02 ~]#
4）关闭lb01的keepalived
systemctl stop keepalived
5 ) lb01检查是否有vip
[root@lb01 ~]# ip a|grep 0.3
[root@lb01 ~]#
6）lb02检查是否有vip
[root@lb02 ~]# ip a|grep 0.3
inet 10.0.0.3/24 scope global secondary eth0:1
总结
当keepalived出故障和断网的时候自动切换到备用负载均衡。keepalived基于服务器，nginx挂了 不会自动切换。下面我们需要解决这件事
keepalived随着nginx关闭而关闭
1.解决什么问题？
1）keepalived基于服务器，nginx挂了 不会自动切换
lb01 lb02操作如下
2.写脚本--lb01 lb02都要写--监视nginx,当nginx被关闭后自动关闭keepalived
[root@lb01 ~]# vim /server/scripts/chk.sh
#!/bin/bash
##脚本:检查nginx是否运行 如果不运行 关闭keepalived
#检查进程数量
count=`ps -ef |grep -c '[n]ginx'`
#检查端口数量
#count=ss -lntup |grep nginx
#count=ps -ef |grep nginx|grep -v grep
#count=ss -lntup |grep -c nginx
#检查端口
#count=lsof -i:80
if [ $count -eq 0 ];then
systemctl stop keepalived
fi
3.配置keepalived配置文件
lb01操作如下
! Configuration File for keepalived
global_defs {
router_id lb01
}
vrrp_script chk_lb {
script "/server/scripts/chk.sh"
interval 2
weight 1
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3/24 dev eth0 label eth0:1
}
track_script {
chk_lb
}
}
lb02配置如下
[root@lb02 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id lb01
}
vrrp_script chk_lb {
script "/server/scripts/chk.sh"
interval 2
weight 1
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3/24 dev eth0 label eth0:1
}
track_script {
chk_lb
}
启动高可用和负载均衡服务
1）启动nginx keepalived
systemctl restart nginx keepalived
2）检查进程---是否启动
[root@lb01 ~]# ps -ef|grep nginx
root 7979 1 0 15:31 ? 00:00:00 nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf
nginx 7980 7979 0 15:31 ? 00:00:00 nginx: worker process
root 8011 7219 0 15:32 pts/0 00:00:00 grep --color=auto nginx
[root@lb01 ~]# ps -ef|grep keepalived
root 7982 1 0 15:31 ? 00:00:00 /usr/sbin/keepalived -D
root 7983 7982 0 15:31 ? 00:00:00 /usr/sbin/keepalived -D
root 7984 7982 0 15:31 ? 00:00:00 /usr/sbin/keepalived -D
root 8033 7219 0 15:32 pts/0 00:00:00 grep --color=auto keepalived
3)检查是否有vip
[root@lb01 ~]# ip a|grep 0.3
inet 10.0.0.3/24 scope global secondary eth0:1 ##ip现在是在lb01上的
[root@lb02 ~]# ip a|grep 0.3
[root@lb02 ~]#
测试
1）关闭lb01上的nginx,并检查进程
[root@lb01 ~]# systemctl stop nginx
[root@lb01 ~]# ps -ef|grep nginx
root 8931 7219 0 15:38 pts/0 00:00:00 grep --color=auto nginx
[root@lb01 ~]# ps -ef|grep keepalived
root 8933 7219 0 15:38 pts/0 00:00:00 grep --color=auto keepalived
[root@lb01 ~]# ip a|grep 0.3
[root@lb01 ~]#
2）lb02检查
[root@lb02 ~]# ip a|grep 0.3
inet 10.0.0.3/24 scope global secondary eth0:1
总结
写个监控nginx服务的脚本，然后在keepalived中使用。这样就可以当nginx出现故障的时候，就关闭keepalived.实现高可用。
keepalived双主模式
解决了什么问题
1）一台主一台备用，只有主故障了以后才会访问备的。这就导致主，压力太大。备压力太小。所有我们需要让他们互为主备。
修改配置文件
lb01配置如下
! Configuration File for keepalived
global_defs {
router_id lb01
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3/24 dev eth0 label eth0:1
}
}
vrrp_instance VI_2 {
state MASTER
interface eth0
virtual_router_id 52
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.4/24 dev eth0 label eth0:2
}
}
lb02配置如下
! Configuration File for keepalived
global_defs {
router_id lb01
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3/24 dev eth0 label eth0:1
}
}
vrrp_instance VI_2 {
state BACKUP
interface eth0
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.4/24 dev eth0 label eth0:2
}
}
测试双主模式
systemctl restart keepalived ##重启keepalived
[root@lb01 ~]# ip a|egrep '0.3|0.4' ##检查lb01 vip
inet 10.0.0.3/24 scope global secondary eth0:1
[root@lb02 ~]# ip a|egrep '0.3|0.4' ##检查lb02 vip
inet 10.0.0.4/24 scope global secondary eth0:2
[root@lb02 ~]# systemctl stop keepalived ##关闭lb02的高可用后
[root@lb02 ~]# ip a|egrep '0.3|0.4' ##lb02的vip 已经不存在了
[root@lb02 ~]#
[root@lb01 ~]# ip a|egrep '0.3|0.4' ##全都跑到了lb01上来了
inet 10.0.0.3/24 scope global secondary eth0:1
inet 10.0.0.4/24 scope global secondary eth0:2
每个域名绑定对应ip
修改配置文件
lb01 lb02都一样
upstream web_pools {
## server 10.0.0.7:80 weight=1 max_fails=3 fail_timeout=10s;
## server 10.0.0.8:80 weight=1 max_fails=3 fail_timeout=10s;
# ip_hash;#加上他用户第一次访问哪台服务器以后就会一直访问那台
server 10.0.0.7:80 weight=1 max_fails=3 fail_timeout=10s;
server 10.0.0.8:80 weight=1 max_fails=3 fail_timeout=10s;
}
server {
listen 10.0.0.3:80;
server_name www.oldboy.com;
location / {
proxy_pass http://web_pools;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $remote_addr;
}
}
server {
listen 10.0.0.4:80;
server_name blog.oldboy.com;
location / {
proxy_pass http://web_pools;
proxy_set_header Host $http_host;
proxy_set_header X-Forwarded-For $remote_addr;
}
}
检查语法却报错
##nginx: [emerg] bind() to 10.0.0.4:80 failed (99: Cannot assign requested address)
把这个10.0.0.4的ip绑定到这台机器 失败了
nginx无法把本地不存在的ip地址进行绑定
修改内核信息
/etc/sysctl.conf
net.ipv4.ip_nonlocal_bind = 1
#生效
sysctl -p
等于修改这个文件
[root@lb01 ~]# cat /proc/sys/net/ipv4/ip_nonlocal_bind
1
然后就可以重启成功了，关于ip的变动需要使用restart 重启