說明：本實驗為雙節點nginx為兩台apache服務器提供負載均衡，本文不是做lvs，所以realserver不是配置在keepalived.conf而是在nginx的配置文件中upstream。
此架構需考慮的問題：
1）Master沒掛，則Master占有vip且nginx運行在Master上
2）Master掛了，則backup搶占vip且在backup上運行nginx服務
3）如果master服務器上的nginx服務掛了，則vip資源轉移到backup服務器上
4）檢測后端服務器的健康狀態
Master和Backup兩邊都開啟nginx服務，無論Master還是Backup，當其中的一個keepalived服務停止后，vip都會漂移到keepalived服務還在的節點上，如果要想使nginx服務掛了，vip也漂移到另一個節點，則必須用腳本或者在配置文件里面用shell命令來控制。
配置步驟如下
1.初始化4台測試server，該關的關了
[root@host101 ~]# vim /etc/hosts 192.168.1.200 ng-vip 192.168.1.101 ng-master 192.168.1.102 ng-slave 192.168.1.161 web1 192.168.1.162 web2 [root@host101 ~]# yum clean all [root@host101 ~]# systemctl stop firewalld.service [root@host101 ~]# systemctl disable firewalld.service [root@host101 ~]# sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config
2.配置web1,web2的apache服務，兩台一樣的方法
[root@host161 ~]# yum -y install httpd [root@host161 ~]# systemctl start httpd [root@host161 ~]# systemctl enable httpd ln -s '/usr/lib/systemd/system/httpd.service' '/etc/systemd/system/multiuser.target.wants/httpd.service' [root@host161 ~]# cat /var/www/html/index.html hello this lvs-web1 [root@host162 ~]# yum -y install httpd [root@host162 ~]# systemctl start httpd [root@host162 ~]# systemctl enable httpd ln -s '/usr/lib/systemd/system/httpd.service' '/etc/systemd/system/multiuser.target.wants/httpd.service' [root@host162 ~]# cat /var/www/html/index.html hello this lvs-web2
3.通過yum安裝配置nginx節點，兩台一樣的方法
[root@host101 ~]# vim /etc/yum.repos.d/nginx.repo
[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/7/x86_64/
gpgcheck=0
enabled=1
[root@host101 ~]# yum clean all
[root@host101 ~]# yum -y install nginx
[root@host101 ~]# vim /usr/share/nginx/html/index.html
<h1>Welcome to ng-master!</h1>
[root@host101 ~]# cd /etc/nginx/conf.d/
[root@host101 conf.d]# mv default.conf default.conf.1
[root@host101 ~]# vim /etc/nginx/conf.d/web.conf
upstream myapp1 {
server web1;
server web2;
}
server {
listen 80;
location / {
proxy_pass http://myapp1;
}
}
[root@host101 ~]# systemctl restart nginx.service
[root@host102 ~]# vim /etc/yum.repos.d/nginx.repo
[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/7/x86_64/
gpgcheck=0
enabled=1
[root@host102 ~]# yum clean all
[root@host102 ~]# yum -y install nginx
[root@host102 ~]# vim /usr/share/nginx/html/index.html
<h1>Welcome to ng-master!</h1>
[root@host102 ~]# cd /etc/nginx/conf.d/
[root@host102 conf.d]# mv default.conf default.conf.1
[root@host102 ~]# vim /etc/nginx/conf.d/web.conf
upstream myapp1 {
server web1;
server web2;
}
server {
listen 80;
location / {
proxy_pass http://myapp1;
}
}
[root@host102 ~]# systemctl restart nginx.service
4.在主nginx服務器上安裝keepalived，並配置nginx服務健康檢測腳本
[root@host101 conf.d]# yum -y install keepalived
[root@host101 conf.d]# cd /etc/keepalived/
[root@host101 keepalived]# cp keepalived.conf keepalived.conf.1
[root@host101 keepalived]# vim keepalived.conf
global_defs {
notification_email {
abc@mail.com
}
notification_email_from abc@mail.com
smtp_server smtp.mail.com
smtp_connect_timeout 30
router_id HA_MASTER1 #表示運行keepalived服務器的一個標識，發郵件時顯示在郵件主題中的信息
}
vrrp_script chk_http_port {
script "/usr/local/keepalived/nginx.sh" ####檢測nginx狀態的腳本鏈接
interval 2
weight 2
}
vrrp_instance VI_2 { #vrrp實例
state MASTER #MASTER/BACKUP
interface eno16777736 ####HA 監測網絡接口
virtual_router_id 51 #虛擬路由標識，是一個數字，同一個VRRP實例使用唯一的標識,master和backup要一樣
priority 100 #用於主從模式，優先級主高於100，從低於100
advert_int 1 #主備之間的通告間隔秒數
authentication { #認證用於主從模式，mater和backup配置一樣
auth_type PASS ###主備切換時的驗證
auth_pass 1111 #密碼
}
track_script {
chk_http_port ### 執行監控的服務
}
virtual_ipaddress {
192.168.1.200/24 dev eno16777736 label eno16777736:1 ###########虛擬ip
}
}
[root@host101 keepalived]# mkdir -p /usr/local/keepalived
[root@host101 keepalived]# vim /usr/local/keepalived/nginx.sh
#!/bin/bash
if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
killall keepalived
fi
[root@host101 keepalived]# chmod 755 /usr/local/keepalived/nginx.sh
[root@host101 keepalived]# systemctl start keepalived
[root@host101 keepalived]# ifconfig -a
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.101 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::20c:29ff:fefe:6f3 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:fe:06:f3 txqueuelen 1000 (Ethernet)
eno16777736:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.200 netmask 255.255.255.0 broadcast 0.0.0.0
ether 00:0c:29:fe:06:f3 txqueuelen 1000 (Ethernet)
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 0 (Local Loopback)
5.在備nginx服務器上安裝keepalived，並配置nginx服務健康檢測腳本，與主略有不同
[root@host102 conf.d]# yum -y install keepalived
[root@host102 conf.d]# cd /etc/keepalived/
[root@host102 keepalived]# cp keepalived.conf keepalived.conf.1
[root@host102 keepalived]# vim keepalived.conf
global_defs {
notification_email {
abc@mail.com
}
notification_email_from abc@mail.com
smtp_server smtp.mail.com
smtp_connect_timeout 30
router_id HA_MASTER1 #表示運行keepalived服務器的一個標識，發郵件時顯示在郵件主題中的信息
}
vrrp_script chk_http_port {
script "/usr/local/keepalived/nginx.sh" ####檢測nginx狀態的腳本鏈接
interval 2
weight 2
}
vrrp_instance VI_2 { #vrrp實例
state BACKUP #MASTER/BACKUP
interface eno16777736 ####HA 監測網絡接口
virtual_router_id 51 #虛擬路由標識，是一個數字，同一個VRRP實例使用唯一的標識,master和backup要一樣
priority 80 #用於主從模式，優先級主高於100，從低於100
advert_int 1 #主備之間的通告間隔秒數
authentication { #認證用於主從模式，mater和backup配置一樣
auth_type PASS ###主備切換時的驗證
auth_pass 1111 #密碼
}
track_script {
chk_http_port ### 執行監控的服務
}
virtual_ipaddress {
192.168.1.200/24 dev eno16777736 label eno16777736:1 ###########虛擬ip
}
}
[root@host102 keepalived]# mkdir -p /usr/local/keepalived
[root@host102 keepalived]# vim /usr/local/keepalived/nginx.sh
#!/bin/bash
if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
killall keepalived
fi
[root@host102 keepalived]# chmod 755 /usr/local/keepalived/nginx.sh
[root@host102 keepalived]# systemctl start keepalived
[root@host102 keepalived]# ifconfig -a
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.102 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::20c:29ff:fe87:fd0e prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:87:fd:0e txqueuelen 1000 (Ethernet)
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 0 (Local Loopback)
6.測試：通過瀏覽器訪問測試http://192.168.1.200/，可發現流量在web1和web2之間跳轉.
6.1測試關閉主nginx節點上的keepalived服務器，發綁定的vip在主節點消失
[root@host101 keepalived]# systemctl stop keepalived.service
[root@host101 keepalived]# ifconfig -a
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.101 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::20c:29ff:fefe:6f3 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:fe:06:f3 txqueuelen 1000 (Ethernet)
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 0 (Local Loopback)
vip在卻在備節點上出現
[root@host102 keepalived]# ifconfig -a
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.102 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::20c:29ff:fe87:fd0e prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:87:fd:0e txqueuelen 1000 (Ethernet)
eno16777736:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.200 netmask 255.255.255.0 broadcast 0.0.0.0
ether 00:0c:29:87:fd:0e txqueuelen 1000 (Ethernet)
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 0 (Local Loopback)
通過瀏覽器訪問測試http://192.168.1.200/，可發現流量依然在web1和web2之間跳轉。
6.2再次啟動主節點的keepalived服務，發現vip又重新漂移會主節點
[root@host101 keepalived]# systemctl start keepalived.service
[root@host101 keepalived]# ifconfig -a
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.101 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::20c:29ff:fefe:6f3 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:fe:06:f3 txqueuelen 1000 (Ethernet)
eno16777736:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.200 netmask 255.255.255.0 broadcast 0.0.0.0
ether 00:0c:29:fe:06:f3 txqueuelen 1000 (Ethernet)
通過瀏覽器訪問測試http://192.168.1.200/，可發現流量依然在web1和web2之間跳轉。
6.3關閉nginx主節點上的nginx服務，發現vip從主節點消失，keepalived服務關閉，vip在備節點上出現。
[root@host101 keepalived]# systemctl stop nginx.service
[root@host101 keepalived]# ifconfig -a
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.101 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::20c:29ff:fefe:6f3 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:fe:06:f3 txqueuelen 1000 (Ethernet)
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 0 (Local Loopback)
[root@host101 keepalived]# systemctl status keepalived
keepalived.service - LVS and VRRP High Availability Monitor
Loaded: loaded (/usr/lib/systemd/system/keepalived.service; disabled)
Active: inactive (dead)
通過瀏覽器訪問測試http://192.168.1.200/，可發現流量依然在web1和web2之間跳轉。
6.4再次啟動主節點的nginx和keepalived服務后，VIP又漂回主節點。
[root@host101 keepalived]# systemctl start nginx.service [root@host101 keepalived]# systemctl start keepalived 通過瀏覽器訪問測試http://192.168.1.200/，可發現流量依然在web1和web2之間跳轉。
參考：
http://www.linuxdiyf.com/linux/12955.html
http://nginx.org/en/linux_packages.html
http://blog.csdn.net/e421083458/article/details/30086413
http://my.oschina.net/u/1458120/blog/208740