1.keepalived介绍
keepalived最初是专为lvs负载均衡软件设计的，用来管理并监控lvs集群系统中各个服务节点的状态，后来又加入了实现高可用的vrrp功能。keepalived除了能够管理lvs软件外，还能支持其他服务的高可用解决方案。
keepalived通过vrrp协议实现高可用功能的。vrrp（virtual router redundancy protocol）虚拟路由冗余协议。vrrp出现的目的就是为了解决静态路由单点故障问题，它能保证当个别节点宕机时，整个网络可以不间断地运行。
2.keepalived高可用故障转移原理
keepalived高可用服务之间的故障转移，是通过vrrp来实现的。在keepalived服务工作时，主master节点会不断地向备节点发送（多播的方式）心跳消息，用来告诉备backup节点自己还活着。
当主节点发生故障时，无法给备节点发送心跳消息，如果备节点无法继续检测到来自主节点的心跳。就会调用自身的接管程序，接管主节点的ip资源和服务。当主节点恢复时，备节点又会释放主节点故障时自身接管的ip资源和服务，恢复到原来的备用角色
3.安装nginx
3.1.主节点（192.168.80.22）
3.1.1.安装编译工具和库文件
yum -y install make zlib zlib-devel gcc-c++ libtool openssl openssl-devel
3.1.2.安装pcre
#进入目录 cd /usr/local/develop/anginx #上传安装文件并解压 tar -zxvf pcre-8.38.tar.gz #进入安装目录 cd pcre-8.38 #检查配置 ./configure #编译、安装 make && make install #查看pcre版本 pcre-config --version
3.1.3.安装nginx
#进入目录 cd /usr/local/develop/anginx #上传安装文件，并解压 tar -zxvf nginx-1.8.1.tar.gz #进入安装目录 cd nginx-1.8.1 #检查配置 ./configure --prefix=/usr/local/develop/anginx/webserver/nginx --with-http_stub_status_module --with-http_ssl_module --with-pcre=/usr/local/develop/anginx/pcre-8.38 #编译安装 make && make install #查看nginx版本 /usr/local/develop/anginx/webserver/nginx/sbin/nginx -v -------------------------------------------------------- [root@hadoop02 webserver]# /usr/local/develop/anginx/webserver/nginx/sbin/nginx -v nginx version: nginx/1.8.1 #配置nginx（检查） /usr/local/develop/anginx/webserver/nginx/sbin/nginx -t #nginx管理命令 /usr/local/develop/anginx/webserver/nginx/sbin/nginx # 启动 nginx /usr/local/develop/anginx/webserver/nginx/sbin/nginx -s stop # 停止 nginx /usr/local/develop/anginx/webserver/nginx/sbin/nginx -s reload # 重新载入配置文件 /usr/local/develop/anginx/webserver/nginx/sbin/nginx -s reopen # 重启 nginx
3.1.4.nginx基础配置
vi nginx.conf
#user nobody;
worker_processes 1;
#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;
pid logs/nginx.pid;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log logs/access.log main;
sendfile on;
#tcp_nopush on;
#keepalive_timeout 0;
keepalive_timeout 65;
#gzip on;
#添加tomcat列表，真实应用服务器都放在这
upstream tomcat_pool{
#server tomcat地址:端口号 weight表示权值，权值越大，被分配的几率越大;
server 192.168.80.22:8080 weight=4 max_fails=2 fail_timeout=30s;
server 192.168.80.22:8081 weight=4 max_fails=2 fail_timeout=30s;
}
server {
listen 80;
server_name tomcat_pool;
#charset koi8-r;
#access_log logs/host.access.log main;
location / {
#root html;
#index index.html index.htm;
proxy_pass http://tomcat_pool; #转向tomcat处理
proxy_set_header host $host;
proxy_set_header x-real-ip $remote_addr;
proxy_set_header x-forwarded-for $proxy_add_x_forwarded_for;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}3.2.备节点（192.168.80.21）
说明：安装方式同nginx主节点。
4.安装keepalived
4.1.主节点（192.168.80.22）
#安装keepalived
yum install keepalived -y
#启动keepalived服务
/etc/init.d/keepalived start
-------------------------------------------
[root@hadoop02 anginx]# /etc/init.d/keepalived start
正在启动 keepalived： [确定]
[root@hadoop02 anginx]# ps -ef |grep keepalived
root 15723 1 0 00:59 ? 00:00:00 /usr/sbin/keepalived -d
root 15724 15723 0 00:59 ? 00:00:00 /usr/sbin/keepalived -d
root 15725 15723 0 00:59 ? 00:00:00 /usr/sbin/keepalived -d
root 15731 15622 0 00:59 pts/1 00:00:00 grep keepalived
[root@hadoop02 anginx]#
#设置开机自启动
echo "/etc/init.d/keepalived start" >>/etc/rc.local
#关闭keepalived服务
/etc/init.d/keepalived stop
#编辑keepalived配置文件
vi /etc/keepalived/keepalived.conf
-----------------------------------------------------------
! configuration file for keepalived
global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from alexandre.cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id lb01
}
vrrp_instance vi_1 {
state master
interface eth1
virtual_router_id 55
priority 150
advert_int 1
authentication {
auth_type pass
auth_pass server123
}
virtual_ipaddress {
192.168.80.100 dev eth1 label eth1:1
}
}
...........................................................关于配置说明：
【router_id】 是路由标识，在一个局域网里面应该是唯一的
【vrrp_instance vi_1】{...}这是一个vrrp实例，里面定义了keepalived的主备状态、接口、优先级、认证和ip信息
【state】 定义了vrrp的角色
【interface】定义使用的接口，这里我的服务器用的网卡都是eth1
【virtual_router_id】是虚拟路由id标识，一组的keepalived配置中主备都是设置一致
【priority】是优先级，数字越大，优先级越大，
【auth_type】是认证方式
【auth_pass】是认证的密码
【virtual_ipaddress】 ｛...｝定义虚拟ip地址，可以配置多个ip地址，这里我定义为192.168.80.100，绑定了eth1的网络接口，虚拟接口eth1:1
4.2.备节点（192.168.80.21）
#安装keepalived
yum install keepalived -y
#启动keepalived服务
/etc/init.d/keepalived start
-------------------------------------------
[root@hadoop02 anginx]# /etc/init.d/keepalived start
正在启动 keepalived： [确定]
[root@hadoop02 anginx]# ps -ef |grep keepalived
root 15723 1 0 00:59 ? 00:00:00 /usr/sbin/keepalived -d
root 15724 15723 0 00:59 ? 00:00:00 /usr/sbin/keepalived -d
root 15725 15723 0 00:59 ? 00:00:00 /usr/sbin/keepalived -d
root 15731 15622 0 00:59 pts/1 00:00:00 grep keepalived
[root@hadoop02 anginx]#
#设置开机自启动
echo "/etc/init.d/keepalived start" >>/etc/rc.local
#关闭keepalived服务
/etc/init.d/keepalived stop
#编辑keepalived配置文件
vi /etc/keepalived/keepalived.conf
-----------------------------------------------------------------
! configuration file for keepalived
global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from alexandre.cassen@firewall.loc
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id lb02
}
vrrp_instance vi_1 {
state backup
interface eth1
virtual_router_id 55
priority 100
advert_int 1
authentication {
auth_type pass
auth_pass server123
}
virtual_ipaddress {
192.168.80.100 dev eth1 label eth1:1
}
}
.............................................................5.测试
5.1.启动主备节点的keepalived服务
#在节点一执行（192.168.80.22） /etc/init.d/keepalived start ------------------------------------- [root@hadoop02 anginx]# ps -ef |grep keepalived root 15788 1 0 01:09 ? 00:00:00 /usr/sbin/keepalived -d root 15790 15788 0 01:09 ? 00:00:00 /usr/sbin/keepalived -d root 15791 15788 0 01:09 ? 00:00:00 /usr/sbin/keepalived -d root 15807 15622 0 01:33 pts/1 00:00:00 grep keepalived [root@hadoop02 anginx]# #在节点二执行（192.168.80.21） /etc/init.d/keepalived start --------------------------------------- [root@hadoop01 ~]# ps -ef |grep keepalived root 11542 1 0 01:30 ? 00:00:00 /usr/sbin/keepalived -d root 11544 11542 0 01:30 ? 00:00:00 /usr/sbin/keepalived -d root 11545 11542 0 01:30 ? 00:00:00 /usr/sbin/keepalived -d root 11550 11512 0 01:33 pts/1 00:00:00 grep keepalived [root@hadoop01 ~]#
5.2.通过虚ip访问服务
http://192.168.80.100/session-redis-demo/
5.3.停止主节点keepalived服务
#在节点一执行（192.168.80.22）
/etc/init.d/keepalived stop
#观察备节点变化
ip addr
-------------------------------------------
[root@hadoop01 ~]# ip addr
1: lo: <loopback,up,lower_up> mtu 65536 qdisc noqueue state unknown
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth1: <broadcast,multicast,up,lower_up> mtu 1500 qdisc pfifo_fast state up qlen 1000
link/ether 00:50:56:38:e5:46 brd ff:ff:ff:ff:ff:ff
inet 192.168.80.21/24 brd 192.168.80.255 scope global eth1
inet 192.168.80.100/32 scope global eth1:1
inet6 fe80::250:56ff:fe38:e546/64 scope link
valid_lft forever preferred_lft forever
[root@hadoop01 ~]#5.4.继续通过虚ip访问服务
http://192.168.80.100/session-redis-demo/
6.keepalived+nginx整合
说明：编写nginx守护脚本，如果nginx服务出现故障，则停止当前节点的keepalived服务。自动切换到备用节点。
6.1.编写nginx守护脚本
vi nginx_check.sh -------------------------------------- #!/bin/bash while true do if [ $(netstat -tlnp|grep nginx|wc -l) -ne 1 ] then /etc/init.d/keepalived stop fi sleep 2 done #给脚本授权 chmod u+x nginx_check.sh #执行脚本 nohup /usr/local/develop/anginx/shell/nginx_check.sh &
6.2.停止主节点nginx服务
#停止主节点nginx服务
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s stop
#查找进程
[root@hadoop02 ~]# ps -ef |grep nginx
root 15915 1 0 01:51 ? 00:00:00 /bin/bash /usr/local/develop/anginx/shell/nginx_check.sh
root 16516 15753 0 01:54 pts/5 00:00:00 grep nginx
[root@hadoop02 ~]#
#观察备用节点变化【服务正常】
ip addr
--------------------------------------
[root@hadoop01 shell]# ip addr
1: lo: <loopback,up,lower_up> mtu 65536 qdisc noqueue state unknown
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth1: <broadcast,multicast,up,lower_up> mtu 1500 qdisc pfifo_fast state up qlen 1000
link/ether 00:50:56:38:e5:46 brd ff:ff:ff:ff:ff:ff
inet 192.168.80.21/24 brd 192.168.80.255 scope global eth1
inet 192.168.80.100/32 scope global eth1:1
inet6 fe80::250:56ff:fe38:e546/64 scope link
valid_lft forever preferred_lft forever
[root@hadoop01 shell]#
#再次重新启动主节点nginx和keepalived服务
/usr/local/develop/anginx/webserver/nginx/sbin/nginx
/etc/init.d/keepalived start 
