1.keepalived介紹
keepalived最初是專為LVS負載均衡軟件設計的，用來管理并監控LVS集群系統中各個服務節點的狀態，后來又加入了實現高可用的VRRP功能。keepalived除了能夠管理LVS軟件外，還能支持其他服務的高可用解決方案。
keepalived通過VRRP協議實現高可用功能的。VRRP（Virtual Router Redundancy Protocol）虛擬路由冗余協議。VRRP出現的目的就是為了解決靜態路由單點故障問題，它能保證當個別節點宕機時，整個網絡可以不間斷地運行。
2.keepalived高可用故障轉移原理
keepalived高可用服務之間的故障轉移，是通過VRRP來實現的。在keepalived服務工作時，主Master節點會不斷地向備節點發送（多播的方式）心跳消息，用來告訴備Backup節點自己還活著。
當主節點發生故障時，無法給備節點發送心跳消息，如果備節點無法繼續檢測到來自主節點的心跳。就會調用自身的接管程序，接管主節點的IP資源和服務。當主節點恢復時，備節點又會釋放主節點故障時自身接管的IP資源和服務，恢復到原來的備用角色
3.安裝nginx
3.1.主節點（192.168.80.22）
3.1.1.安裝編譯工具和庫文件
yum -y install make zlib zlib-devel gcc-c++ libtool openssl openssl-devel
3.1.2.安裝pcre
#進入目錄
cd /usr/local/develop/anginx
#上傳安裝文件并解壓
tar -zxvf pcre-8.38.tar.gz
#進入安裝目錄
cd pcre-8.38
#檢查配置
./configure
#編譯、安裝
make && make install
#查看pcre版本
pcre-config --version
3.1.3.安裝nginx
#進入目錄
cd /usr/local/develop/anginx
#上傳安裝文件，并解壓
tar -zxvf nginx-1.8.1.tar.gz
#進入安裝目錄
cd nginx-1.8.1
#檢查配置
./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
#編譯安裝
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（檢查）
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -t
#nginx管理命令
/usr/local/develop/anginx/webserver/nginx/sbin/nginx # 啟動 Nginx
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s stop # 停止 Nginx
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s reload # 重新載入配置文件
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s reopen # 重啟 Nginx
3.1.4.nginx基礎配置
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，真實應用服務器都放在這
upstream tomcat_pool{
#server tomcat地址:端口號 weight表示權值，權值越大，被分配的幾率越大;
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; #轉向tomcat處理
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.備節點（192.168.80.21）
說明：安裝方式同nginx主節點。
4.安裝keepalived
4.1.主節點（192.168.80.22）
#安裝keepalived
yum install keepalived -y
#啟動keepalived服務
/etc/init.d/keepalived start
-------------------------------------------
[root@hadoop02 anginx]# /etc/init.d/keepalived start
正在啟動 keepalived： [確定]
[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]#
#設置開機自啟動
echo "/etc/init.d/keepalived start" >>/etc/rc.local
#關閉keepalived服務
/etc/init.d/keepalived stop
#編輯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
}
}
...........................................................
關于配置說明：
- 【router_id】 是路由標識，在一個局域網里面應該是唯一的
- 【vrrp_instance VI_1】{...}這是一個VRRP實例，里面定義了keepalived的主備狀態、接口、優先級、認證和IP信息
- 【state】 定義了VRRP的角色
- 【interface】定義使用的接口，這里我的服務器用的網卡都是eth1
- 【virtual_router_id】是虛擬路由ID標識，一組的keepalived配置中主備都是設置一致
- 【priority】是優先級，數字越大，優先級越大，
- 【auth_type】是認證方式
- 【auth_pass】是認證的密碼
- 【virtual_ipaddress】 ｛...｝定義虛擬IP地址，可以配置多個IP地址，這里我定義為192.168.80.100，綁定了eth1的網絡接口，虛擬接口eth1:1
4.2.備節點（192.168.80.21）
#安裝keepalived
yum install keepalived -y
#啟動keepalived服務
/etc/init.d/keepalived start
-------------------------------------------
[root@hadoop02 anginx]# /etc/init.d/keepalived start
正在啟動 keepalived： [確定]
[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]#
#設置開機自啟動
echo "/etc/init.d/keepalived start" >>/etc/rc.local
#關閉keepalived服務
/etc/init.d/keepalived stop
#編輯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.測試
5.1.啟動主備節點的keepalived服務
#在節點一執行（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]#
#在節點二執行（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.通過虛ip訪問服務
http://192.168.80.100/session-redis-demo/
5.3.停止主節點keepalived服務
#在節點一執行（192.168.80.22）
/etc/init.d/keepalived stop
#觀察備節點變化
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.繼續通過虛ip訪問服務
http://192.168.80.100/session-redis-demo/
6.keepalived+nginx整合
說明：編寫nginx守護腳本，如果nginx服務出現故障，則停止當前節點的keepalived服務。自動切換到備用節點。
6.1.編寫nginx守護腳本
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
#給腳本授權
chmod u+x nginx_check.sh
#執行腳本
nohup /usr/local/develop/anginx/shell/nginx_check.sh &
6.2.停止主節點nginx服務
#停止主節點nginx服務
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s stop
#查找進程
[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 ~]#
#觀察備用節點變化【服務正常】
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]#
#再次重新啟動主節點nginx和keepalived服務
/usr/local/develop/anginx/webserver/nginx/sbin/nginx
/etc/init.d/keepalived start
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。
