Keepalived+Nginx+Tomcat 实现高可用Web集群的示例代码

Keepalived+Nginx+Tomcat 实现高可用Web集群

 

一、Nginx的安装过程

1.下载Nginx安装包,安装依赖环境包

(1)安装 C++编译环境

yum -y install gcc  #C++

(2)安装pcre

yum -y install pcre-devel

(3)安装zlib

yum -y install zlib-devel

(4)安装Nginx

定位到nginx 解压文件位置,执行编译安装命令

[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)启动Nginx

安装完成后先寻找那安装完成的目录位置

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

进入Nginx子目录sbin启动Nginx

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

查看Nginx是否启动

或通过进程查看Nginx启动情况

[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安装完成并启动成功。

(6)Nginx快捷启动和开机启动配置

编辑Nginx快捷启动脚本【 注意Nginx安装路径 需要根据自己的NGINX路径进行改动

[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

为启动脚本授权 并加入开机启动

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

启动Nginx

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

将Nginx加入系统环境变量

[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):              [ 确定 ]

Tips: 快捷命令

service nginx (start|stop|restart)

二、KeepAlived安装和配置

1.安装Keepalived依赖环境

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

2.编译Keepalived并安装

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

3.将Keepalive 安装成系统服务

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

手动复制默认的配置文件到默认路径

[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/

为keepalived 创建软链接

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

设置Keepalived开机自启动

[root@localhost sysconfig]# chkconfig keepalived on
注意:正在将请求转发到“systemctl enable keepalived.service”。
Created symlink from /etc/systemd/system/multi-user.target.wants/keepalived.service to /usr/lib/systemd/system/keepalived.service

启动Keepalived服务

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

关闭Keepalived服务

[root@localhost keepalived]# killall keepalived

三、集群规划和搭建

环境准备:

CentOS 7.2

Keepalived   Version 1.4.0 - December 29, 2017

Nginx           Version: nginx/1.12.2

Tomcat         Version:8

集群规划清单

虚拟机 IP 说明
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 虚拟漂移IP

1.更改Tomcat默认欢迎页面,用于标识切换Web

更改TomcatServer01 节点ROOT/index.jsp 信息,加入TomcatIP地址,并加入Nginx值,即修改节点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 节点ROOT/index.jsp信息,加入TomcatIP地址,并加入Nginx值,即修改节点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.启动Tomcat服务,查看Tomcat服务IP信息,此时Nginx未启动,因此request-header没有Nginx信息。

 

3.配置Nginx代理信息

1.配置Master节点[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节点[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.启动Master 节点Nginx服务

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

此时访问 192.168.43.101 可以看到103和104节点Tcomat交替显示,说明Nginx服务已经将请求负载到了2台tomcat上。

 

4.同理配置Backup[192.168.43.102] Nginx信息,启动Nginx后,访问192.168.43.102后可以看到Backup节点已起到负载的效果。

 

4.配置Keepalived 脚本信息

1. 在Master节点和Slave节点 /etc/keepalived目录下添加check_nginx.sh 文件,用于检测Nginx的存货状况,添加keepalived.conf文件

check_nginx.sh文件信息如下:

#!/bin/bash
#时间变量,用于记录日志
d=`date --date today +%Y%m%d_%H:%M:%S`
#计算nginx进程数量
n=`ps -C nginx --no-heading|wc -l`
#如果进程为0,则启动nginx,并且再次检测nginx进程数量,
#如果还为0,说明nginx无法启动,此时需要关闭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,为check_nginx.sh 文件授权,便于脚本获得执行权限。

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

2.在Master 节点 /etc/keepalived目录下,添加keepalived.conf 文件,具体信息如下:

vrrp_script chk_nginx { 
 script "/etc/keepalived/check_nginx.sh"  //检测nginx进程的脚本 
 interval 2 
 weight -20 
} 

global_defs { 
 notification_email { 
   //可以添加邮件提醒 
 } 
} 
vrrp_instance VI_1 { 
 state MASTER         #标示状态为MASTER 备份机为BACKUP
 interface ens33        #设置实例绑定的网卡(ip addr查看,需要根据个人网卡绑定)
 virtual_router_id 51     #同一实例下virtual_router_id必须相同  
 mcast_src_ip 192.168.43.101  
 priority 250         #MASTER权重要高于BACKUP 比如BACKUP为240 
 advert_int 1         #MASTER与BACKUP负载均衡器之间同步检查的时间间隔,单位是秒
 nopreempt           #非抢占模式
 authentication {       #设置认证
    auth_type PASS     #主从服务器验证方式
    auth_pass 123456 
 } 
 track_script { 
    check_nginx 
 } 
 virtual_ipaddress {      #设置vip
    192.168.43.150     #可以多个虚拟IP,换行即可
 } 
}

3.在Backup节点 etc/keepalived目录下添加 keepalived.conf 配置文件

信息如下:

vrrp_script chk_nginx { 
 script "/etc/keepalived/check_nginx.sh"  //检测nginx进程的脚本 
 interval 2 
 weight -20 
} 

global_defs { 
 notification_email { 
   //可以添加邮件提醒 
 } 
} 
vrrp_instance VI_1 { 
 state BACKUP         #标示状态为MASTER 备份机为BACKUP
 interface ens33        #设置实例绑定的网卡(ip addr查看)
 virtual_router_id 51     #同一实例下virtual_router_id必须相同  
 mcast_src_ip 192.168.43.102  
 priority 240         #MASTER权重要高于BACKUP 比如BACKUP为240 
 advert_int 1         #MASTER与BACKUP负载均衡器之间同步检查的时间间隔,单位是秒
 nopreempt           #非抢占模式
 authentication {       #设置认证
    auth_type PASS     #主从服务器验证方式
    auth_pass 123456 
 } 
 track_script { 
    check_nginx 
 } 
 virtual_ipaddress {      #设置vip
    192.168.43.150     #可以多个虚拟IP,换行即可
 } 
}

Tips: 关于配置信息的几点说明

  • state - 主服务器需配成MASTER,从服务器需配成BACKUP
  • interface - 这个是网卡名,我使用的是VM12.0的版本,所以这里网卡名为ens33
  • mcast_src_ip - 配置各自的实际IP地址
  • priority - 主服务器的优先级必须比从服务器的高,这里主服务器配置成250,从服务器配置成240
  • virtual_ipaddress - 配置虚拟IP(192.168.43.150)
  • authentication - auth_pass主从服务器必须一致,keepalived靠这个来通信
  • virtual_router_id - 主从服务器必须保持一致

 5.集群高可用(HA)验证

Step1 启动Master机器的Keepalived和 Nginx服务

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

查看服务启动进程

[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启动进程

[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 查看虚拟IP绑定情况,如出现192.168.43.150 节点信息则绑定到Master节点

[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 启动Backup节点Nginx服务和Keepalived服务,查看服务启动情况,如Backup节点出现了虚拟IP,则Keepalvied配置文件有问题,此情况称为脑裂。

[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 验证服务

浏览并多次强制刷新地址: http://192.168.43.150 ,可以看到103和104多次交替显示,并显示Nginx-1,则表明 Master节点在进行web服务转发。

 Step 4 关闭Master keepalived服务和Nginx服务,访问Web服务观察服务转移情况

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

此时强制刷新192.168.43.150发现 页面交替显示103和104并显示Nginx-2 ,VIP已转移到192.168.43.102上,已证明服务自动切换到备份节点上。

Step 5 启动Master Keepalived 服务和Nginx服务

此时再次验证发现,VIP已被Master重新夺回,并页面交替显示 103和104,此时显示Nginx-1

四、Keepalived抢占模式和非抢占模式

keepalived的HA分为抢占模式和非抢占模式,抢占模式即MASTER从故障中恢复后,会将VIP从BACKUP节点中抢占过来。非抢占模式即MASTER恢复后不抢占BACKUP升级为MASTER后的VIP。

非抢占模式配置:

1> 在vrrp_instance块下两个节点各增加了nopreempt指令,表示不争抢vip

2> 节点的state都为BACKUP 两个keepalived节点都启动后,默认都是BACKUP状态,双方在发送组播信息后,会根据优先级来选举一个MASTER出来。由于两者都配置了nopreempt,所以MASTER从故障中恢复后,不会抢占vip。这样会避免VIP切换可能造成的服务延迟。

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持龙方网络。

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郑重声明:本文版权归原作者所有,转载文章仅为传播更多信息之目的,如作者信息标记有误,请第一时间联系我们修改或删除,多谢。

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