Keepalived 是一种高性能的服务器高可用或热备解决方案， Keepalived 可以用来防止服务器单点故障的发生，通过配合 Nginx 可以实现 web 前端服务的高可用。
| 主机名 | IP地址 | 虚拟IP | 角色 |
| lb01 | 192.168.203.150 | 192.168.203.88 | keepalived（Master） |
| lb02 | 192.168.203.148 | 192.168.203.89 | keepalived（Backup） |
| web1 | 192.168.203.136 | nginx | |
| web2 | 192.168.203.135 | nginx |
需要准备的依赖包和安装包
[root@web1 ~]# ls | grep tar*
keepalived-2.0.2.tar.gz
libevent-2.1.12-stable.tar.gz
nginx-1.6.0.tar.gz
openssl-1.0.1h.tar.gz
pcre-8.35.tar.gz
zlib-1.2.8.tar.gz安装openssl
[root@web1 ~]# tar -xf openssl-1.0.1h.tar.gz
[root@web1 ~]# cd openssl-1.0.1h/
[root@web1 openssl-1.0.1h]# ./config --prefix=/usr/local/openssl
[root@web1 openssl-1.0.1h]# make && make install安装pcre
[root@web1 ~]# tar -xf pcre-8.35.tar.gz
[root@web1 ~]# cd pcre-8.35/
[root@web1 pcre-8.35]# ./configure --prefix=/usr/local/pcre
[root@web1 pcre-8.35]# make && make install安装zlib
[root@web1 ~]# tar -xf zlib-1.2.8.tar.gz
[root@web1 ~]# cd zlib-1.2.8/
[root@web1 zlib-1.2.8]# ./configure --prefix=/usr/local/zlib
[root@web1 zlib-1.2.8]# make && make install
安装Nginx
[root@web1 src]# wget http://nginx.org/download/nginx-1.6.0.tar.gz
[root@web1 src]# tar -xf nginx-1.6.0.tar.gz
[root@web1 src]# cd nginx-1.6.0/
[root@web1 nginx-1.6.0]# ./configure --prefix=/usr/local/nginx --with-openssl=../openssl-1.0.1h --with-pcre=../pcre-8.35 --with-zlib=../zlib-1.2.8 --with-http_ssl_module
[root@web1 nginx-1.6.0]# make && make install
[root@web1 nginx-1.6.0]# useradd www -s /sbin/nologin -M # 创建用户修改Nginx配置文件
[root@web1 conf]# egrep -v "#|^$" nginx.conf
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
server {
listen 80;
server_name 192.168.203.136;
charset utf-8;
location / {
root html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}
[root@web1 conf]#启动Nginx
[root@web1 ~]# /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
[root@web1 ~]# /usr/local/nginx/sbin/nginx -s reload
查看nginx进程启动情况
[root@web1 ~]# ps -ef | grep nginx
root 54235 1 0 17:51 ? 00:00:00 nginx: master process /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
www 54244 54235 0 17:51 ? 00:00:00 nginx: worker process
root 54258 8945 0 17:51 pts/0 00:00:00 grep --color=auto nginx
[root@web1 ~]# 基于域名配置nginx虚拟主机
[root@web1 nginx]# cd html
[root@web1 html]# mkdir www
[root@web1 html]# vim www/index.html
192.168.203.136 www.chd.comm
[root@web1 html]# cd ..
[root@web1 nginx]# sbin/nginx -t # 检查语句
nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful
[root@web1 nginx]# sbin/nginx # 启动nginx
[root@web1 nginx]# sbin/nginx -s reload # 重启nginx
[root@web1 nginx]# ps -ef |grep nginx # 查看nginx进程号
nobody 509 130219 0 15:19 ? 00:00:00 nginx: worker process
root 512 111842 0 15:19 pts/2 00:00:00 grep --color=auto nginx
root 130219 1 0 14:34 ? 00:00:00 nginx: master process /usr/local/nginx/sbin/nginx
[root@web1 nginx]# echo "192.168.203.136 www.chd.com mail.chd.com mail.cnd.com" >>/etc/hosts 将解析追加到hosts文件中
[root@web1 nginx]# tail -1 /etc/hosts # 查看hosts文件最后一行内容
192.168.203.136 www.chd.com ftp.chd.com mail.chd.com
[root@web1 nginx]#打开浏览器，输入IP地址访问Nginx
Nginx开机自启动
[root@web1 ~]# vim /etc/rc.local
/usr/local/nginx/sbin/nginx
配置一个简单的负载均衡
修改lb01服务器的nginx.conf主配置文件
[root@web1 nginx]# cat conf/nginx.conf | grep -v "^#"
user www www;
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
gzip on;
upstream webServer {
server 192.168.203.135:80 weight=5;
server 192.168.203.136:80 weight=6;
}
server {
listen 80;
server_name www.chd.cn;
charset utf-8;
#access_log logs/host.access.log main;
location / {
proxy_pass http://webServer;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}修改lb02服务器的nginx.conf主配置文件
[root@web2 nginx]# cat conf/nginx.conf | grep -v "^#"
user www www;
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
gzip on;
upstream webServer {
server 192.168.203.135:80 weight=5;
server 192.168.203.136:80 weight=6;
}
server {
listen 80;
server_name 192.168.203.148;
charset utf-8;
#access_log logs/host.access.log main;
location / {
root html;
index index.html index.htm;
proxy_pass http://webServer;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}验证：在解析www.chd.cn服务器的时候会在web1和web2之间切换
[root@lb01 nginx]# curl www.chd.cn
192.168.203.135 www.chd.com
[root@lb01 nginx]# curl www.chd.cn
192.168.203.136 www.chd.com配置keepalived负载均衡
安装Keepalived
1.yum安装：
yum install keepalived -y # 推荐使用yum安装，简单、快捷、高效
2.源码包安装：
[root@lb01 ~]# ls | grep keepalived*
keepalived-2.0.2.tar.gz
[root@lb01 ~]# tar -xf keepalived-2.0.2.tar.gz
[root@lb01 ~]# cd keepalived-2.0.2/
[root@lb01 keepalived-2.0.2]# ./configure --prefix=/usr/local/keepalived
[root@lb01 keepalived-2.0.2]# make && make install
[root@lb01 keepalived-2.0.2]# cp keepalived/etc/init.d/keepalived /etc/init.d/
[root@lb01 keepalived-2.0.2]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[root@lb01 keepalived-2.0.2]# mkdir /etc/keepalived
[root@lb01 keepalived-2.0.2]# chmod +755 /etc/keepalived/
[root@lb01 keepalived-2.0.2]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
[root@lb01 keepalived-2.0.2]# ln -s /usr/local/keepalived/sbin/keepalived /usr/sbin/
[root@lb01 keepalived-2.0.2]# ./keepalived/etc/init.d/keepalived start
Starting keepalived: [ OK ]
[root@lb01 keepalived-2.0.2]#
注意：在编译时发出警告解决办法
*** WARNING - this build will not support IPVS with IPv6. Please install libnl/libnl-3 dev libraries to support IPv6 with IPVS.
安装
[root@localhost keepalived-2.0.2]# yum -y install libnl libnl-devel
[root@localhost keepalived-2.0.2]# yum install -y libnfnetlink-devel
| 主配置文件 | /etc/keepalived/keepalived.conf |
| 环境配置文件 | /etc/sysconfig/keepalived |
修改lb1的/etc/keepalived/keepalived.conf配置文件
[root@lb01 nginx]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id lb1
vrrp_skip_check_adv_addr
vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.203.88/24
}
}
virtual_server 192.168.203.88 80 {
delay_loop 6
lb_algo rr
lb_kind DR
persistence_timeout 50
protocol TCP
}
[root@lb01 nginx]# /etc/init.d/keepalived restart
Restarting keepalived (via systemctl): [ OK ]
[root@lb01 nginx]# ip addr | grep 192.168.203.88
inet 192.168.203.88/24 scope global secondary ens33
[root@lb01 nginx]#修改lb2的/etc/keepalived/keepalived.conf配置文件
[root@lb02 nginx]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id lb02
vrrp_skip_check_adv_addr
vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 52
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.203.88/24
}
}
virtual_server 192.168.203.88 80 {
delay_loop 6
lb_algo rr
lb_kind DR
persistence_timeout 50
protocol TCP
}
[root@lb02 ~]# /etc/init.d/keepalived restart
Restarting keepalived (via systemctl): [ OK ]
[root@lb02 ~]# ip addr | grep 192.168.203.88
[root@lb02 ~]#可以看到现在是主节点接管的虚拟IP地址，如果把master主节点down了，看backup备节点会不会自动接管keepalived
[root@lb01 nginx]# /etc/init.d/keepalived stop
Stopping keepalived (via systemctl): [ OK ]
[root@lb01 nginx]#
[root@lb02 nginx]# ip addr | grep 192.168.203.88
inet 192.168.203.88/24 scope global secondary ens33
[root@lb02 nginx]#可以看到backup备节点已经自动接管了虚拟IP地址！
[root@lb01 nginx]# /etc/init.d/keepalived restart
Restarting keepalived (via systemctl): [ OK ]
[root@lb01 nginx]# ip addr | grep 192.168.203.88
inet 192.168.203.88/24 scope global secondary ens33
[root@lb01 nginx]#如果把主节点启动起来，那么主节点又会自动接管keepalived服务
配置keepalived双主模式
修改lb1的/etc/keepalived/keepalived.conf配置文件
[root@lb01 nginx]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id lb1
vrrp_skip_check_adv_addr
vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.203.88/24
}
}
vrrp_instance VI_2 {
state BACKUP
interface ens33
virtual_router_id 53
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.203.89/24
}
} 修改lb2的/etc/keepalived/keepalived.conf配置文件
[root@lb02 nginx]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id lb02
vrrp_skip_check_adv_addr
vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 52
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.203.88/24
}
}
virtual_server 192.168.203.88 80 {
delay_loop 6
lb_algo rr
lb_kind DR
persistence_timeout 50
protocol TCP
}
vrrp_instance VI_2 {
state MASTER
interface ens33
virtual_router_id 53
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.203.89/24
}
} 修改完配置文件之后重启keepalived
[root@lb01 nginx]# /etc/init.d/keepalived restart
Restarting keepalived (via systemctl): [ OK ]
[root@lb01 nginx]# ip add|egrep "192.168.203.88|192.168.203.89"
inet 192.168.203.88/24 scope global secondary ens33重启backup备节点之后可以看到虚拟IP地址 192.168.203.89已经被备节点接管了
[root@lb02 nginx]# /etc/init.d/keepalived restart
Restarting keepalived (via systemctl): [ OK ]
[root@lb02 nginx]# ip add|egrep "192.168.203.88|192.168.203.89"
inet 192.168.203.89/24 scope global secondary ens33
[root@lb02 nginx]#把master主节点down了，查看backup备节点的状态
[root@lb01 nginx]# /etc/init.d/keepalived stop
Stopping keepalived (via systemctl): [ OK ]
[root@lb01 nginx]# ip add|egrep "192.168.203.88|192.168.203.89"
[root@lb01 nginx]#可以看到master主节点down了之后，backup备节点接管了两个虚拟IP地址
[root@lb02 nginx]# ip add|egrep "192.168.203.88|192.168.203.89"
inet 192.168.203.89/24 scope global secondary ens33
inet 192.168.203.88/24 scope global secondary ens33如果此时将master主节点再次启动，又会重新接管192.168.203.88
[root@lb01 nginx]# /etc/init.d/keepalived start
Starting keepalived (via systemctl): [ OK ]
[root@lb01 nginx]# ip add|egrep "192.168.203.88|192.168.203.89"
inet 192.168.203.88/24 scope global secondary ens33
[root@lb01 nginx]#而备节点的状态也会很快释放192.168.203.88
[root@lb02 nginx]# ip add|egrep "192.168.203.88|192.168.203.89"
inet 192.168.203.89/24 scope global secondary ens33
[root@lb02 nginx]#把backup备节点down之后，看master主节点的状态
[root@lb02 nginx]# /etc/init.d/keepalived stop
Stopping keepalived (via systemctl): [ OK ]
[root@lb02 nginx]# ip add|egrep "192.168.203.88|192.168.203.89"
[root@lb02 nginx]#可以看到master主节点很快就接管了192.168.203.89
[root@lb01 nginx]# ip add|egrep "192.168.203.88|192.168.203.89"
inet 192.168.203.88/24 scope global secondary ens33
inet 192.168.203.89/24 scope global secondary ens33
[root@lb01 nginx]#至此nginx + keepalived高可用集群实现负载均衡完成
总结：不管是lb1主节点、lb2备节点任意一端down了，虚拟IP地址都会被互相切换接管，当down的节点再次启动时，虚拟IP又会被重新接管回来！