Keepalived

Nginx

Tomcat

1、規劃

虛IP：192.168.56.101

真實IP |主機名 |Nginx埠|Tomcat埠|主從

192.168.56.103|leo.dis2| 88 | 8080 |主

192.168.56.104|leo.dis3| 88 | 8080 |從

CentOS6.8

Nginx 1.13.1

Keepalived 1.3.5

Tomcat7.0.78

JDK1.8.0_131

參看我以前的文章，打開防火牆埠。

2、安裝Nginx

使用root用戶，安裝依賴包：

yum install gcc gcc-c++ make automake autoconf libtool pcre pcre-devel zlib zlib-devel openssl openssl-devel

把Nginx包放到/usr/local/src內，解壓縮並安裝：

tar -zxvf nginx-1.13.1.tar.gz

cd nginx-1.13.1

./configure --prefix=/usr/local/nginx

make && make install

3、配置Nginx

vi /usr/local/nginx/conf/nginx.conf

在開頭增加：

user root;

監聽埠80改為88。

vi /usr/local/nginx/html/index.html

分別給兩台伺服器的Nginx頁面增加103/104的標識。

啟動Nginx

/usr/local/nginx/sbin/nginx

# 重新載入配置文件

/usr/local/nginx/sbin/nginx -s reload

# 重啟 Nginx

/usr/local/nginx/sbin/nginx -s reopen

# 停止 Nginx

/usr/local/nginx/sbin/nginx -s stop

4、Nginx開機啟動

vi /etc/rc.local

添加 /usr/local/nginx/sbin/nginx

5、Keepalived安裝

安裝依賴包：

yum install openssl-devel libnl3-devel ipset-devel iptables-devel libnfnetlink-devel popt popt-static popt-devel gcc kernel-headers kernel-devel net-snmp-devel -y

把Keepalived包放到/usr/local/src內，解壓縮並安裝：

tar -zxvf keepalived-1.3.5.tar.gz

cd keepalived-1.3.5

./configure --prefix=/usr/local/nginx

make && make install

6、設置為開機啟動

接下來是跟很多教程不一樣的地方。

在很多教程里，安裝完畢後下一步應該是複製、鏈接一些文件，以便把keepalived設置成系統服務，但是請注意/usr/local/keepalived/etc/rc.d/init.d/keepalived這個文件，教程上都說有這個文件，複製到/etc/init.d/即可，可是在我安裝過程中，沒有這個目錄和文件，所以要按照以下的方法來處理：

mkdir -p /etc/keepalived

cd /usr/local/keepalived/

ln -s /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

ln -s /usr/local/keepalived/sbin/keepalived /usr/sbin/

ln -s /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

touch /etc/rc.d/init.d/keepalived

chmod +x /etc/rc.d/init.d/keepalived

vi /etc/rc.d/init.d/keepalived

keepalived腳本內容：

#!/bin/sh

#

# keepalived High Availability monitor built upon LVS and VRRP

#

# chkconfig: - 86 14

# description: Robust keepalive facility to the Linux Virtual Server project

# with multilayer TCP/IP stack checks.

### BEGIN INIT INFO

# Provides: keepalived

# Required-Start: $local_fs $network $named $syslog

# Required-Stop: $local_fs $network $named $syslog

# Should-Start: smtpdaemon httpd

# Should-Stop: smtpdaemon httpd

# Default-Start:

# Default-Stop: 0 1 2 3 4 5 6

# Short-Description: High Availability monitor built upon LVS and VRRP

# Description: Robust keepalive facility to the Linux Virtual Server

# project with multilayer TCP/IP stack checks.

### END INIT INFO

# Source function library.

. /etc/rc.d/init.d/functions

exec="/usr/sbin/keepalived"

prog="keepalived"

config="/etc/keepalived/keepalived.conf"

[ -e /etc/sysconfig/$prog ] && . /etc/sysconfig/$prog

lockfile=/var/lock/subsys/keepalived

start() {

[ -x $exec ] || exit 5

[ -e $config ] || exit 6

echo -n $"Starting $prog: "

daemon $exec $KEEPALIVED_OPTIONS

retval=$?

echo

[ $retval -eq 0 ] && touch $lockfile

return $retval

}

stop() {

echo -n $"Stopping $prog: "

killproc $prog

retval=$?

echo

[ $retval -eq 0 ] && rm -f $lockfile

return $retval

}

restart() {

stop

start

}

reload() {

echo -n $"Reloading $prog: "

killproc $prog -1

retval=$?

echo

return $retval

}

force_reload() {

restart

}

rh_status() {

status $prog

}

rh_status_q() {

rh_status &>/dev/null

}

case "$1" in

start)

rh_status_q && exit 0

$1

;;

stop)

rh_status_q || exit 0

$1

;;

restart)

$1

;;

reload)

rh_status_q || exit 7

$1

;;

force-reload)

force_reload

;;

status)

rh_status

;;

condrestart|try-restart)

rh_status_q || exit 0

restart

;;

*)

echo $"Usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload}"

exit 2

esac

exit $?

注意腳本裡面的目錄，要跟上面cp、ln的目錄一致。

設置服務開機啟動：

chkconfig --add keepalived

chkconfig --level 35 keepalived on

7、設置Keepalived

主節點（192.168.56.103）：

vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {

router_id leo.dis2 #主機名

}

vrrp_script chk_nginx {

script "/etc/keepalived/nginx_check.sh"

interval 2

weight -20

}

vrrp_instance VI_1 {

state MASTER#主節點 建議設置為BACKUP，具體解釋見後

interface eth1#指定監測的網卡

virtual_router_id 101#虛擬路由ID，節點保持一致

mcast_src_ip 192.168.56.103 #本機IP

priority 100#權重

nopreempt#設置為不搶佔資源

advert_int 1

authentication {

auth_type PASS

auth_pass 1357924680

}

track_script {

chk_nginx

}

virtual_ipaddress {

192.168.56.101#虛擬IP

}

}

從節點（192.168.56.104）：

vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {

router_id leo.dis3

}

vrrp_script chk_nginx {

script "/etc/keepalived/nginx_check.sh"

interval 2

weight -20

}

vrrp_instance VI_1 {

state BACKUP

interface eth1

virtual_router_id 101

mcast_src_ip 192.168.56.104

priority 90

nopreempt

advert_int 1

authentication {

auth_type PASS

auth_pass 1357924680

}

track_script {

chk_nginx

}

virtual_ipaddress {

192.168.56.101

}

}

注意：nopreempt這個選項要解釋解釋。

這個設置項，允許一個priority比較低的節點作為master，即使有priority更高的節點啟動。

通常如果master服務死掉後backup會變成master，但是當master服務又好了的時候 master此時會搶佔VIP，這樣就會發生兩次切換對業務繁忙的網站來說是不好的。

所以我們要在配置文件加入 nopreempt 非搶佔，但是這個參數只能用於state 為backup，故我們在用的時候最好master 和backup的state都設置成backup 讓其通過priority來競爭。

但是我在測試的時候，不管怎麼配置， VIP資源總是會被搶佔，後來查資料說要在防火牆上開啟組播：

vi /etc/sysconfig/iptables

#組播

-A INPUT -d 224.0.0.18 -j ACCEPT

重啟防火牆。

監測Nginx腳本：

#!/bin/bash

A=`ps -C nginx –no-header |wc -l`

if [ $A -eq 0 ];then

/usr/local/nginx/sbin/nginx

sleep 2

if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then

killall keepalived

fi

fi

腳本賦權：

chmod +x /etc/keepalived/nginx_check.sh

啟動Keepalived：

service keepalived start

8、驗證

啟動Nginx、Keepalived。

分別訪問：http://192.168.56.103:88/ http://192.168.56.104:88/ 會看到之前做的標識。

訪問http://192.168.56.101:88/ 會看到103的標識。

關閉103的KA，刷新頁面則會看到104的標識。

9、Nginx+Tomcat負載均衡

Nginx+Tomcat負載均衡的教程特別多，不再多介紹，簡單提幾個點。

1）兩個nginx.conf修改以下幾處：

#增加

upstream tomcat.com{

#Tomcat1

192.168.56.103:8080 weight=1;

#Tomcat2

192.168.56.104:8080 weight=1;

}

#修改

location / {

#root html;

#index index.html index.htm;

proxy_pass http://tomcat.com;

proxy_redirect default;

}

2）JDK要安裝，防火牆要打開埠。

3）修改兩個Tomcat/webapps/ROOT/index.jsp，分別做上標識。

訪問http://192.168.56.101:88，即可看到不同標識的Tomcat主頁。

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