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Keepalived+Nginx+Tomcat 實現(xiàn)高可用Web集群

一、Nginx的安裝過程

1.下載Nginx安裝包，安裝依賴環(huán)境包

(1)安裝 C++編譯環(huán)境

yum -y install gcc #C++

(2)安裝pcre

yum -y install pcre-devel

(3)安裝zlib

yum -y install zlib-devel

(4)安裝Nginx

定位到nginx 解壓文件位置，執(zhí)行編譯安裝命令

[root@localhost nginx-1.12.2]# pwd
/usr/local/nginx/nginx-1.12.2
[root@localhost nginx-1.12.2]# ./configure && make && make install

(5)啟動Nginx

安裝完成后先尋找那安裝完成的目錄位置

[root@localhost nginx-1.12.2]# whereis nginx
nginx: /usr/local/nginx
[root@localhost nginx-1.12.2]#

進入Nginx子目錄sbin啟動Nginx

[root@localhost sbin]# ls
nginx
[root@localhost sbin]# ./nginx &
[1] 5768
[root@localhost sbin]#

查看Nginx是否啟動

或通過進程查看Nginx啟動情況

[root@localhost sbin]# ps -aux|grep nginx
root  5769 0.0 0.0 20484 608 ?  Ss 14:03 0:00 nginx: master process ./nginx
nobody  5770 0.0 0.0 23012 1620 ?  S 14:03 0:00 nginx: worker process
root  5796 0.0 0.0 112668 972 pts/0 R+ 14:07 0:00 grep --color=auto nginx
[1]+ 完成     ./nginx
[root@localhost sbin]#

到此Nginx安裝完成并啟動成功。

(6)Nginx快捷啟動和開機啟動配置

編輯Nginx快捷啟動腳本【 注意Nginx安裝路徑 ， 需要根據(jù)自己的NGINX路徑進行改動 】

[root@localhost init.d]# vim /etc/rc.d/init.d/nginx

#!/bin/sh
#
# nginx - this script starts and stops the nginx daemon
#
# chkconfig: - 85 15
# description: Nginx is an HTTP(S) server, HTTP(S) reverse \

# proxy and IMAP/POP3 proxy server
# processname: nginx
# config: /etc/nginx/nginx.conf
# config: /usr/local/nginx/conf/nginx.conf
# pidfile: /usr/local/nginx/logs/nginx.pid
 
# Source function library.
. /etc/rc.d/init.d/functions
 
# Source networking configuration.
. /etc/sysconfig/network
 
# Check that networking is up.
[ "$NETWORKING" = "no" ] && exit 0
nginx="/usr/local/nginx/sbin/nginx"
prog=$(basename $nginx)
NGINX_CONF_FILE="/usr/local/nginx/conf/nginx.conf"
[ -f /etc/sysconfig/nginx ] && . /etc/sysconfig/nginx
lockfile=/var/lock/subsys/nginx
 
make_dirs() {
 # make required directories
 user=`$nginx -V 2>&1 | grep "configure arguments:" | sed 's/[^*]*--user=\([^ ]*\).*/\1/g' -`
 if [ -z "`grep $user /etc/passwd`" ]; then
 useradd -M -s /bin/nologin $user
 fi
 options=`$nginx -V 2>&1 | grep 'configure arguments:'`
 for opt in $options; do
 if [ `echo $opt | grep '.*-temp-path'` ]; then
 value=`echo $opt | cut -d "=" -f 2`
 if [ ! -d "$value" ]; then
 # echo "creating" $value
 mkdir -p $value && chown -R $user $value
 fi
 fi
 done
}
 
start() {
 [ -x $nginx ] || exit 5
 [ -f $NGINX_CONF_FILE ] || exit 6
 make_dirs
 echo -n $"Starting $prog: "
 daemon $nginx -c $NGINX_CONF_FILE
 retval=$?
 echo
 [ $retval -eq 0 ] && touch $lockfile
 return $retval
}
 
stop() {
 echo -n $"Stopping $prog: "
 killproc $prog -QUIT
 retval=$?
 echo
 [ $retval -eq 0 ] && rm -f $lockfile
 return $retval
}
 
restart() {
 #configtest || return $?
 stop
 sleep 1
 start
}
 
reload() {
 #configtest || return $?
 echo -n $"Reloading $prog: "
 killproc $nginx -HUP
 RETVAL=$?
 echo
}
 
force_reload() {
 restart
}
 
configtest() {
 $nginx -t -c $NGINX_CONF_FILE
}
 
rh_status() {
 status $prog
}
 
rh_status_q() {
 rh_status >/dev/null 2>&1
}
 
case "$1" in
start)
rh_status_q && exit 0
$1
;;
stop)
 
rh_status_q || exit 0
$1
;;
restart|configtest)
$1
;;
reload)
rh_status_q || exit 7
$1
;;
force-reload)
force_reload
;;
status)
rh_status
;;
condrestart|try-restart)
rh_status_q || exit 0
;;
*)
echo $"Usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload|configtest}"
exit 2
esac

為啟動腳本授權并加入開機啟動

[root@localhost init.d]# chmod -R 777 /etc/rc.d/init.d/nginx 
[root@localhost init.d]# chkconfig nginx

啟動Nginx

[root@localhost init.d]# ./nginx start

將Nginx加入系統(tǒng)環(huán)境變量

[root@localhost init.d]# echo 'export PATH=$PATH:/usr/local/nginx/sbin'>>/etc/profile && source /etc/profile

Nginx命令 [ service nginx (start|stop|restart) ]

[root@localhost init.d]# service nginx start
Starting nginx (via systemctl):       [ 確定 ]

Tips: 快捷命令

service nginx (start|stop|restart)

二、KeepAlived安裝和配置

1.安裝Keepalived依賴環(huán)境

yum install -y popt-devel  
yum install -y ipvsadm
yum install -y libnl*
yum install -y libnf*
yum install -y openssl-devel

2.編譯Keepalived并安裝

[root@localhost keepalived-1.3.9]# ./configure
[root@localhost keepalived-1.3.9]# make && make install

3.將Keepalive 安裝成系統(tǒng)服務

[root@localhost etc]# mkdir /etc/keepalived
[root@localhost etc]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

手動復制默認的配置文件到默認路徑

[root@localhost etc]# mkdir /etc/keepalived
[root@localhost etc]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[root@localhost etc]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

為keepalived 創(chuàng)建軟鏈接

[root@localhost sysconfig]# ln -s /usr/local/keepalived/sbin/keepalived /usr/sbin/

設置Keepalived開機自啟動

[root@localhost sysconfig]# chkconfig keepalived on
注意：正在將請求轉發(fā)到“systemctl enable keepalived.service”。
Created symlink from /etc/systemd/system/multi-user.target.wants/keepalived.service to /usr/lib/systemd/system/keepalived.service

啟動Keepalived服務

[root@localhost keepalived]# keepalived -D -f /etc/keepalived/keepalived.conf

關閉Keepalived服務

[root@localhost keepalived]# killall keepalived

三、集群規(guī)劃和搭建

環(huán)境準備：

CentOS 7.2

Keepalived Version 1.4.0 - December 29, 2017

Nginx Version: nginx/1.12.2

Tomcat Version:8

集群規(guī)劃清單

虛擬機	IP	說明
Keepalived+Nginx1[Master]	192.168.43.101	Nginx Server 01
Keeepalived+Nginx[Backup]	192.168.43.102	Nginx Server 02
Tomcat01	192.168.43.103	Tomcat Web Server01
Tomcat02	192.168.43.104	Tomcat Web Server02
VIP	192.168.43.150	虛擬漂移IP

1.更改Tomcat默認歡迎頁面，用于標識切換Web

更改TomcatServer01 節(jié)點ROOT/index.jsp 信息，加入TomcatIP地址，并加入Nginx值，即修改節(jié)點192.168.43.103信息如下：

<div id="asf-box">
 <h1>${pageContext.servletContext.serverInfo}(192.168.224.103)<%=request.getHeader("X-NGINX")%></h1>
</div>

更改TomcatServer02 節(jié)點ROOT/index.jsp信息，加入TomcatIP地址，并加入Nginx值，即修改節(jié)點192.168.43.104信息如下：

<div id="asf-box">
 <h1>${pageContext.servletContext.serverInfo}(192.168.224.104)<%=request.getHeader("X-NGINX")%></h1>
</div>

2.啟動Tomcat服務，查看Tomcat服務IP信息，此時Nginx未啟動，因此request-header沒有Nginx信息。

3.配置Nginx代理信息

1.配置Master節(jié)點[192.168.43.101]代理信息

upstream tomcat {
 server 192.168.43.103:8080 weight=1;
 server 192.168.43.104:8080 weight=1;
}
server{
 location / {
  proxy_pass http://tomcat;
 proxy_set_header X-NGINX "NGINX-1";
 }
 #......其他省略
}

2.配置Backup節(jié)點[192.168.43.102]代理信息

upstream tomcat {
 server 192.168.43.103:8080 weight=1;
 server 192.168.43.104:8080 weight=1;
}
server{
 location / {
  proxy_pass http://tomcat;
 proxy_set_header X-NGINX "NGINX-2";
 }
 #......其他省略
}

3.啟動Master 節(jié)點Nginx服務

[root@localhost init.d]# service nginx start
Starting nginx (via systemctl):       [ 確定 ]

此時訪問 192.168.43.101 可以看到103和104節(jié)點Tcomat交替顯示，說明Nginx服務已經(jīng)將請求負載到了2臺tomcat上。

4.同理配置Backup[192.168.43.102] Nginx信息，啟動Nginx后，訪問192.168.43.102后可以看到Backup節(jié)點已起到負載的效果。

4.配置Keepalived 腳本信息

1. 在Master節(jié)點和Slave節(jié)點 /etc/keepalived目錄下添加check_nginx.sh 文件，用于檢測Nginx的存貨狀況，添加keepalived.conf文件

check_nginx.sh文件信息如下：

#!/bin/bash
#時間變量，用于記錄日志
d=`date --date today +%Y%m%d_%H:%M:%S`
#計算nginx進程數(shù)量
n=`ps -C nginx --no-heading|wc -l`
#如果進程為0，則啟動nginx，并且再次檢測nginx進程數(shù)量，
#如果還為0，說明nginx無法啟動，此時需要關閉keepalived
if [ $n -eq "0" ]; then
  /etc/rc.d/init.d/nginx start
  n2=`ps -C nginx --no-heading|wc -l`
  if [ $n2 -eq "0" ]; then
    echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
    systemctl stop keepalived
  fi
fi

添加完成后，為check_nginx.sh 文件授權，便于腳本獲得執(zhí)行權限。

[root@localhost keepalived]# chmod -R 777 /etc/keepalived/check_nginx.sh

2.在Master 節(jié)點 /etc/keepalived目錄下，添加keepalived.conf 文件，具體信息如下：

vrrp_script chk_nginx { 
 script "/etc/keepalived/check_nginx.sh" //檢測nginx進程的腳本 
 interval 2 
 weight -20 
} 

global_defs { 
 notification_email { 
  //可以添加郵件提醒 
 } 
} 
vrrp_instance VI_1 { 
 state MASTER     #標示狀態(tài)為MASTER 備份機為BACKUP
 interface ens33    #設置實例綁定的網(wǎng)卡(ip addr查看，需要根據(jù)個人網(wǎng)卡綁定)
 virtual_router_id 51   #同一實例下virtual_router_id必須相同 
 mcast_src_ip 192.168.43.101 
 priority 250     #MASTER權重要高于BACKUP 比如BACKUP為240 
 advert_int 1     #MASTER與BACKUP負載均衡器之間同步檢查的時間間隔，單位是秒
 nopreempt      #非搶占模式
 authentication {    #設置認證
  auth_type PASS   #主從服務器驗證方式
  auth_pass 123456 
 } 
 track_script { 
  check_nginx 
 } 
 virtual_ipaddress {   #設置vip
  192.168.43.150   #可以多個虛擬IP，換行即可
 } 
}

3.在Backup節(jié)點 etc/keepalived目錄下添加 keepalived.conf 配置文件

信息如下：

vrrp_script chk_nginx { 
 script "/etc/keepalived/check_nginx.sh" //檢測nginx進程的腳本 
 interval 2 
 weight -20 
} 

global_defs { 
 notification_email { 
  //可以添加郵件提醒 
 } 
} 
vrrp_instance VI_1 { 
 state BACKUP     #標示狀態(tài)為MASTER 備份機為BACKUP
 interface ens33    #設置實例綁定的網(wǎng)卡(ip addr查看)
 virtual_router_id 51   #同一實例下virtual_router_id必須相同 
 mcast_src_ip 192.168.43.102 
 priority 240     #MASTER權重要高于BACKUP 比如BACKUP為240 
 advert_int 1     #MASTER與BACKUP負載均衡器之間同步檢查的時間間隔，單位是秒
 nopreempt      #非搶占模式
 authentication {    #設置認證
  auth_type PASS   #主從服務器驗證方式
  auth_pass 123456 
 } 
 track_script { 
  check_nginx 
 } 
 virtual_ipaddress {   #設置vip
  192.168.43.150   #可以多個虛擬IP，換行即可
 } 
}

Tips: 關于配置信息的幾點說明

state - 主服務器需配成MASTER，從服務器需配成BACKUP
interface - 這個是網(wǎng)卡名，我使用的是VM12.0的版本，所以這里網(wǎng)卡名為ens33
mcast_src_ip - 配置各自的實際IP地址
priority - 主服務器的優(yōu)先級必須比從服務器的高，這里主服務器配置成250，從服務器配置成240
virtual_ipaddress - 配置虛擬IP（192.168.43.150）
authentication - auth_pass主從服務器必須一致，keepalived靠這個來通信
virtual_router_id - 主從服務器必須保持一致

5.集群高可用(HA)驗證

Step1 啟動Master機器的Keepalived和 Nginx服務

[root@localhost keepalived]# keepalived -D -f /etc/keepalived/keepalived.conf
[root@localhost keepalived]# service nginx start

查看服務啟動進程

[root@localhost keepalived]# ps -aux|grep nginx
root  6390 0.0 0.0 20484 612 ?  Ss 19:13 0:00 nginx: master process /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
nobody  6392 0.0 0.0 23008 1628 ?  S 19:13 0:00 nginx: worker process
root  6978 0.0 0.0 112672 968 pts/0 S+ 20:08 0:00 grep --color=auto nginx

查看Keepalived啟動進程

[root@localhost keepalived]# ps -aux|grep keepalived
root  6402 0.0 0.0 45920 1016 ?  Ss 19:13 0:00 keepalived -D -f /etc/keepalived/keepalived.conf
root  6403 0.0 0.0 48044 1468 ?  S 19:13 0:00 keepalived -D -f /etc/keepalived/keepalived.conf
root  6404 0.0 0.0 50128 1780 ?  S 19:13 0:00 keepalived -D -f /etc/keepalived/keepalived.conf
root  7004 0.0 0.0 112672 976 pts/0 S+ 20:10 0:00 grep --color=auto keepalived

使用 ip add 查看虛擬IP綁定情況，如出現(xiàn)192.168.43.150 節(jié)點信息則綁定到Master節(jié)點

[root@localhost keepalived]# ip add
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
 inet 127.0.0.1/8 scope host lo
  valid_lft forever preferred_lft forever
 inet6 ::1/128 scope host 
  valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
 link/ether 00:0c:29:91:bf:59 brd ff:ff:ff:ff:ff:ff
 inet 192.168.43.101/24 brd 192.168.43.255 scope global ens33
  valid_lft forever preferred_lft forever
 inet 192.168.43.150/32 scope global ens33
  valid_lft forever preferred_lft forever
 inet6 fe80::9abb:4544:f6db:8255/64 scope link 
  valid_lft forever preferred_lft forever
 inet6 fe80::b0b3:d0ca:7382:2779/64 scope link tentative dadfailed 
  valid_lft forever preferred_lft forever
 inet6 fe80::314f:5fe7:4e4b:64ed/64 scope link tentative dadfailed 
  valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000
 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff
 inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
  valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000
 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff

Step 2 啟動Backup節(jié)點Nginx服務和Keepalived服務，查看服務啟動情況，如Backup節(jié)點出現(xiàn)了虛擬IP，則Keepalvied配置文件有問題，此情況稱為腦裂。

[root@localhost keepalived]# clear
[root@localhost keepalived]# ip add
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
 inet 127.0.0.1/8 scope host lo
  valid_lft forever preferred_lft forever
 inet6 ::1/128 scope host 
  valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
 link/ether 00:0c:29:14:df:79 brd ff:ff:ff:ff:ff:ff
 inet 192.168.43.102/24 brd 192.168.43.255 scope global ens33
  valid_lft forever preferred_lft forever
 inet6 fe80::314f:5fe7:4e4b:64ed/64 scope link 
  valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000
 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff
 inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
  valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000
 link/ether 52:54:00:2b:74:aa brd ff:ff:ff:ff:ff:ff

Step 3 驗證服務

瀏覽并多次強制刷新地址： http://192.168.43.150 ,可以看到103和104多次交替顯示，并顯示Nginx-1,則表明 Master節(jié)點在進行web服務轉發(fā)。

Step 4 關閉Master keepalived服務和Nginx服務，訪問Web服務觀察服務轉移情況

[root@localhost keepalived]# killall keepalived
[root@localhost keepalived]# service nginx stop

此時強制刷新192.168.43.150發(fā)現(xiàn) 頁面交替顯示103和104并顯示Nginx-2 ，VIP已轉移到192.168.43.102上，已證明服務自動切換到備份節(jié)點上。

Step 5 啟動Master Keepalived 服務和Nginx服務

此時再次驗證發(fā)現(xiàn)，VIP已被Master重新奪回，并頁面交替顯示 103和104，此時顯示Nginx-1

四、Keepalived搶占模式和非搶占模式

keepalived的HA分為搶占模式和非搶占模式，搶占模式即MASTER從故障中恢復后，會將VIP從BACKUP節(jié)點中搶占過來。非搶占模式即MASTER恢復后不搶占BACKUP升級為MASTER后的VIP。

非搶占模式配置：

1> 在vrrp_instance塊下兩個節(jié)點各增加了nopreempt指令，表示不爭搶vip

2> 節(jié)點的state都為BACKUP 兩個keepalived節(jié)點都啟動后，默認都是BACKUP狀態(tài)，雙方在發(fā)送組播信息后，會根據(jù)優(yōu)先級來選舉一個MASTER出來。由于兩者都配置了nopreempt，所以MASTER從故障中恢復后，不會搶占vip。這樣會避免VIP切換可能造成的服務延遲。

以上就是本文的全部內(nèi)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。

標簽：上海福州安康鷹潭德宏淮安樂山泰安

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