HAproxy+keepalived+tomcat部署高可用负载均衡实践

pengdott2025-05-01 20:01

目录

一、前言

二、服务器规划

三、部署

1、jdk18安装

2、tomcat安装

3、haproxy安装

4、keepalived安装

三、测试

1、服务器停机测试

2、停止haproxy服务测试

总结

一、前言

HAProxy是一个使用C语言编写的自由及开放源代码软件，其提供高可用性、负载均衡，以及基于TCP和HTTP的应用程序代理。Keepalived ‌是一个基于VRRP（Virtual Router Redundancy Protocol）协议的高可用性解决方案。本文基于以上两种技术，以apachetomcat作为WEB应用服务器实现高可用负载均衡的部署。

二、服务器规划

共计四台服务器以及一个VIP（192.168.100.135），具体软件部署如下所示，所以服务器均安装RockyLinux9.5操作系统。关于RockyLinux9.5参见Rocky Linux 9.5操作系统安装_rocky linux 9.5安装-CSDN博客

|--------|-----------------|---------------|--------------|-------------------------------|
| 类别 | IP | OS | hostname | 安装软件 |
| 负载均衡 | 192.168.100.131 | RockyLinux9.5 | lb-haproxy1 | haproxy2.4.22，keepalived2.2.8 |
| 负载均衡 | 192.168.100.132 | RockyLinux9.5 | lb-haproxy2 | haproxy2.4.22，keepalived2.2.8 |
| WEB应用 | 192.168.100.133 | RockyLinux9.5 | web-tomcat1 | jdk18，apache tomcat11 |
| WEB应用 | 192.168.100.134 | RockyLinux9.5 | web-tomcat2 | jdk18，apache tomcat11 |

三、部署

1、jdk18安装

以下内容在web-tomcat1，web-tomcat2中执行

（1）、将安装文件jdk-18.0.2.1_linux-x64_bin.tar.gz拷贝到/usr/local目录下

（2）、解压文件tar -zxvf jdk-18.0.2.1_linux-x64_bin.tar.gz，解压后usr/local目录下出现文件夹jdk-18.0.2.1，该文件夹内容如下：

bash 复制代码 
[root@web-tomcat1 local]# ls -l jdk-18.0.2.1
total 24
drwxr-xr-x  2 root  root  4096 Apr 29 10:51 bin
drwxr-xr-x  5 root  root   123 Apr 29 10:51 conf
drwxr-xr-x  3 root  root   132 Apr 29 10:51 include
drwxr-xr-x  2 root  root  4096 Apr 29 10:51 jmods
drwxr-xr-x 72 root  root  4096 Apr 29 10:51 legal
drwxr-xr-x  5 root  root  4096 Apr 29 10:51 lib
lrwxrwxrwx  1 10668 10668   23 Aug 16  2022 LICENSE -> legal/java.base/LICENSE
drwxr-xr-x  3 root  root    18 Apr 29 10:51 man
-rw-r--r--  1 10668 10668  290 Aug 16  2022 README
-rw-r--r--  1 10668 10668 1233 Aug 16  2022 release

（3）、进入该目录，生成jre文件夹不然在运行tomcat时会报缺失jre的错误。执行如下命令：

./bin/jlink --module-path jmods --add-modules java.desktop --output jre，完成后jdk-18.0.2.1目录下出现jre文件夹

bash 复制代码 
[root@web-tomcat1 jdk-18.0.2.1]# ls -l
total 24
drwxr-xr-x  2 root  root  4096 Apr 29 10:51 bin
drwxr-xr-x  5 root  root   123 Apr 29 10:51 conf
drwxr-xr-x  3 root  root   132 Apr 29 10:51 include
drwxr-xr-x  2 root  root  4096 Apr 29 10:51 jmods
drwxr-xr-x  8 root  root    94 Apr 29 11:00 jre
...........................................

（4）、配置jdk环境变量，通过vim /etc/profile命令在profile文件中加入以下内容，完成后执行source /etc/profile命令使之生效。

bash 复制代码 
export JAVA_HOME=/usr/local/jdk-18.0.2.1
export PATH=$JAVA_HOME/bin:$PATH
export JRE_HOME=${JAVA_HOME}
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib

（5）、执行java -version命令查看jdk版本，确认jdk安装完成

bash 复制代码 
[root@web-tomcat1 /]# java -version
java version "18.0.2.1" 2022-08-18
Java(TM) SE Runtime Environment (build 18.0.2.1+1-1)
Java HotSpot(TM) 64-Bit Server VM (build 18.0.2.1+1-1, mixed mode, sharing)

2、tomcat安装

以下内容在web-tomcat1，web-tomcat2中执行，安装前关闭防火墙及selinux

（1）、将安装文件apache-tomcat-11.0.6.tar.gz拷贝到/usr/local目录下

（2）、tar -zxvf apache-tomcat-11.0.6.tar.gz，解压后usr/local目录下出现文件夹apache-tomcat-11.0.6，该文件夹内容如下：

bash 复制代码 
[root@test-web1 apache-tomcat-11.0.6]# ls -l
total 140
drwxr-x--- 2 root root  4096 Apr 22 10:50 bin
-rw-r----- 1 root root 24262 Apr  1 22:40 BUILDING.txt
drwx------ 3 root root  4096 Apr 24 16:50 conf
-rw-r----- 1 root root  6166 Apr  1 22:40 CONTRIBUTING.md
drwxr-x--- 2 root root  4096 Apr 22 10:50 lib
-rw-r----- 1 root root 60517 Apr  1 22:40 LICENSE
drwxr-x--- 2 root root  4096 Apr 29 10:07 logs
-rw-r----- 1 root root  2333 Apr  1 22:40 NOTICE
-rw-r----- 1 root root  3291 Apr  1 22:40 README.md
-rw-r----- 1 root root  6469 Apr  1 22:40 RELEASE-NOTES
-rw-r----- 1 root root 16109 Apr  1 22:40 RUNNING.txt
drwxr-x--- 2 root root    30 Apr 22 10:50 temp
drwxr-x--- 7 root root    81 Apr  1 22:40 webapps
drwxr-x--- 3 root root    22 Apr 22 13:27 work

（3）、配置tomcat环境变量，通过vim /etc/profile命令在profile文件中加入以下内容，完成后执行source /etc/profile命令使之生效。

bash 复制代码 
export CATALINA_HOME=//usr/local/apache-tomcat-11.0.6
export PATH=${CATALINA_HOME}/bin:$PATH

（4）、执行命令./apache-tomcat-11.0.6/bin/version.sh查看tomcat环境变量及版本信息

bash 复制代码 
Using CATALINA_BASE:   //usr/local/apache-tomcat-11.0.6
Using CATALINA_HOME:   //usr/local/apache-tomcat-11.0.6
Using CATALINA_TMPDIR: //usr/local/apache-tomcat-11.0.6/temp
Using JRE_HOME:        /usr/local/jdk-18.0.2.1
Using CLASSPATH:       //usr/local/apache-tomcat-11.0.6/bin/bootstrap.jar://usr/local/apache-tomcat-11.0.6/bin/tomcat-juli.jar
Using CATALINA_OPTS:   
Server version: Apache Tomcat/11.0.6
Server built:   Apr 1 2025 14:40:40 UTC
Server number:  11.0.6.0
OS Name:        Linux
OS Version:     5.14.0-503.14.1.el9_5.x86_64
Architecture:   amd64
JVM Version:    18.0.2.1+1-1
JVM Vendor:     Oracle Corporation

（5）、启动tomcat，进入目录/usr/local/apache-tomcat-11.0.6/bin，执行命令./startup.sh，看到如下内容说明tomcat启动成功

bash 复制代码 
[root@web-tomcat2 ~]# cd /usr/local/apache-tomcat-11.0.6/bin
[root@web-tomcat2 bin]# ./startup.sh
Using CATALINA_BASE:   //usr/local/apache-tomcat-11.0.6
Using CATALINA_HOME:   //usr/local/apache-tomcat-11.0.6
Using CATALINA_TMPDIR: //usr/local/apache-tomcat-11.0.6/temp
Using JRE_HOME:        /usr/local/jdk-18.0.2.1
Using CLASSPATH:       //usr/local/apache-tomcat-11.0.6/bin/bootstrap.jar://usr/local/apache-tomcat-11.0.6/bin/tomcat-juli.jar
Using CATALINA_OPTS:   
Tomcat started.

（6）、修改tomcat首页内容，为了后期体现出负载均衡haproxy服务访问不同的服务器，这将tomcat首页内容进行了一点修改，即修改/usr/local/apache-tomcat-11.0.6/webapps/ROOT/index.jsp页面内容。web-tomcat1服务器index.jsp页面此处修改为：

<span id="nav-home"><a href="${tomcatUrl}">FIRST,FIRST,FIRST</a></span>

web-tomcat1服务器index.jsp页面此处修改为：

<span id="nav-home"><a href="${tomcatUrl}">SECOND,SECOND,SECOND</a></span>

（7）、通过浏览器分别访问两台服务器的tomcat，验证安装完成

web-tomcat1首页

web-tomcat2首页

（8）、通过自定义service文件，设定tomcat自动启动。进入目录/etc/systemd/system/，创建tomcat.service文件，输入如下内容，保存后执行命令systemctl enable tomcat.service，完成开机自动启动的设定。

bash 复制代码 
[Unit]
Description=Tomcat11
After=network.target
 
[Service]
Type=forking
Environment="JAVA_HOME=/usr/local/jdk-18.0.2.1"  
Environment="CATALINA_HOME=/usr/local/apache-tomcat-11.0.6" 
Environment="CATALINA_BASE=/usr/local/apache-tomcat-11.0.6" 
Environment="CATALINA_OPTS=-Xms512M -Xmx1024M -server -XX:+UseParallelGC" 
Environment="JAVA_OPTS=-Djava.awt.headless=true -Djava.security.egd=file:///dev/urandom"
ExecStart=/usr/local/apache-tomcat-11.0.6/bin/startup.sh
ExecStop=/usr/local/apache-tomcat-11.0.6/bin/shutdown.sh
ExecReload=/bin/kill -s HUP $MAINPID
RemainAfterExit=yes
 
[Install]
WantedBy=multi-user.target

重启服务器验证tomcat服务状态，可以看到tomcat服务处于运行之中。

bash 复制代码 
[root@web-tomcat1 system]# systemctl list-units --type=service --state=running | grep tomcat
  tomcat.service                loaded active running Tomcat11

3、haproxy安装

以下内容在lb-haproxy1，lb-haproxy2中执行，安装前关闭防火墙及selinux。

（1）、通过yum install -y haproxy命令进行安装，执行过程如下：

bash 复制代码 
[root@lb-haproxy1 local]# yum install -y haproxy
Last metadata expiration check: 4:21:21 ago on Tue 29 Apr 2025 10:27:00 AM CST.
Dependencies resolved.
========================================================================================================================================================
 Package                          Architecture                    Version                                      Repository                          Size
========================================================================================================================================================
Installing:
 haproxy                          x86_64                          2.4.22-3.el9_5.1                             appstream                          2.2 M

Transaction Summary
========================================================================================================================================================
Install  1 Package

Total download size: 2.2 M
Installed size: 6.6 M
Downloading Packages:
haproxy-2.4.22-3.el9_5.1.x86_64.rpm                                                                                     2.5 MB/s | 2.2 MB     00:00    
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                   1.4 MB/s | 2.2 MB     00:01     
Rocky Linux 9 - AppStream                                                                                               1.7 MB/s | 1.7 kB     00:00    
Importing GPG key 0x350D275D:
 Userid     : "Rocky Enterprise Software Foundation - Release key 2022 <[email protected]>"
 Fingerprint: 21CB 256A E16F C54C 6E65 2949 702D 426D 350D 275D
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-Rocky-9
Key imported successfully
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                                                                                1/1 
  Running scriptlet: haproxy-2.4.22-3.el9_5.1.x86_64                                                                                                1/1 
  Installing       : haproxy-2.4.22-3.el9_5.1.x86_64                                                                                                1/1 
  Running scriptlet: haproxy-2.4.22-3.el9_5.1.x86_64                                                                                                1/1 
  Verifying        : haproxy-2.4.22-3.el9_5.1.x86_64                                                                                                1/1 

Installed:
  haproxy-2.4.22-3.el9_5.1.x86_64                                                                                                                       

Complete!
[root@lb-haproxy1 local]#

通过haproxy -v命令查看haproxy版本信息。

bash 复制代码 
[root@lb-haproxy1 haproxy]# haproxy -v
HAProxy version 2.4.22-f8e3218 2023/02/14 - https://haproxy.org/
Status: long-term supported branch - will stop receiving fixes around Q2 2026.
Known bugs: http://www.haproxy.org/bugs/bugs-2.4.22.html
Running on: Linux 5.14.0-503.14.1.el9_5.x86_64 #1 SMP PREEMPT_DYNAMIC Fri Nov 15 12:04:32 UTC 2024 x86_64

（2）、启动haproxy服务，设定开机自动启动，并查看服务状态为active。

bash 复制代码 
[root@lb-haproxy1 local]# systemctl start haproxy
[root@lb-haproxy1 local]# systemctl enable haproxy
Created symlink /etc/systemd/system/multi-user.target.wants/haproxy.service → /usr/lib/systemd/system/haproxy.service.
[root@lb-haproxy1 local]# systemctl status haproxy
● haproxy.service - HAProxy Load Balancer
     Loaded: loaded (/usr/lib/systemd/system/haproxy.service; enabled; preset: disabled)
     Active: active (running) since Tue 2025-04-29 14:53:55 CST; 10s ago
   Main PID: 33813 (haproxy)
      Tasks: 3 (limit: 22798)
     Memory: 4.1M
        CPU: 40ms
     CGroup: /system.slice/haproxy.service
             ├─33813 /usr/sbin/haproxy -Ws -f /etc/haproxy/haproxy.cfg -f /etc/haproxy/conf.d -p /run/haproxy.pid
             └─33815 /usr/sbin/haproxy -Ws -f /etc/haproxy/haproxy.cfg -f /etc/haproxy/conf.d -p /run/haproxy.pid

Apr 29 14:53:55 lb-haproxy1 systemd[1]: Started HAProxy Load Balancer.
Apr 29 14:53:55 lb-haproxy1 haproxy[33815]: [WARNING]  (33815) : Server static/static is DOWN, reason: Layer4 connection problem, info: "Connection ref>
Apr 29 14:53:55 lb-haproxy1 haproxy[33815]: [NOTICE]   (33815) : haproxy version is 2.4.22-f8e3218
Apr 29 14:53:55 lb-haproxy1 haproxy[33815]: [NOTICE]   (33815) : path to executable is /usr/sbin/haproxy
Apr 29 14:53:55 lb-haproxy1 haproxy[33815]: [ALERT]    (33815) : backend 'static' has no server available!
Apr 29 14:53:55 lb-haproxy1 haproxy[33815]: [WARNING]  (33815) : Server app/app1 is DOWN, reason: Layer4 connection problem, info: "Connection refused">
Apr 29 14:53:56 lb-haproxy1 haproxy[33815]: [WARNING]  (33815) : Server app/app2 is DOWN, reason: Layer4 connection problem, info: "Connection refused">
Apr 29 14:53:56 lb-haproxy1 haproxy[33815]: [WARNING]  (33815) : Server app/app3 is DOWN, reason: Layer4 connection problem, info: "Connection refused">
Apr 29 14:53:56 lb-haproxy1 haproxy[33815]: [WARNING]  (33815) : Server app/app4 is DOWN, reason: Layer4 connection problem, info: "Connection refused">
Apr 29 14:53:56 lb-haproxy1 haproxy[33815]: [ALERT]    (33815) : backend 'app' has no server available!
lines 1-21/21 (END)

（3）、修改haproxy的配置使之可以访问后端tomcat服务器，将以下内容加入/etc/haproxy/目录下haproxy.cfg文件中，之后通过systemctl restart haproxy.service命令重启haproxy服务。

bash 复制代码 
#---------------------------------------------------------------------
# Example configuration for a possible web application.  See the
# full configuration options online.
#
#   https://www.haproxy.org/download/1.8/doc/configuration.txt
#
#---------------------------------------------------------------------

#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
    # to have these messages end up in /var/log/haproxy.log you will
    # need to:
    #
    # 1) configure syslog to accept network log events.  This is done
    #    by adding the '-r' option to the SYSLOGD_OPTIONS in
    #    /etc/sysconfig/syslog
    #
    # 2) configure local2 events to go to the /var/log/haproxy.log
    #   file. A line like the following can be added to
    #   /etc/sysconfig/syslog
    #
    #local2.*                       /var/log/haproxy.log
    #
    log         127.0.0.1 local2

    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

    # turn on stats unix socket
    stats socket /var/lib/haproxy/stats
    stats timeout 30s
    

    # utilize system-wide crypto-policies
    ssl-default-bind-ciphers PROFILE=SYSTEM
    ssl-default-server-ciphers PROFILE=SYSTEM

#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000

frontend http_front
    bind *:80
    # 如果使用HTTPS，取消以下注释并配置证书
    # bind *:443 ssl crt /etc/haproxy/yourdomain.pem
    # redirect scheme https if !{ ssl_fc }
    
    # 定义ACL规则（可选）
    # acl is_tomcat path_beg /yourcontextpath
    
    # 使用默认后端
    default_backend tomcat_servers

#---------------------------------------------------------------------
# static backend for serving up images, stylesheets and such
#---------------------------------------------------------------------
backend static
    balance     roundrobin
    server      static 127.0.0.1:4331 check

#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
backend tomcat_servers
    balance roundrobin  # 负载均衡算法
    option forwardfor   # 添加X-Forwarded-For头，建议tomcat server.xml加入相应设置
    http-request set-header X-Forwarded-Port %[dst_port]
    http-request add-header X-Forwarded-Proto https if { ssl_fc }
    
    # 配置Tomcat服务器
    server web-tomcat1 192.168.100.133:8080 check
    server web-tomcat2 192.168.100.134:8080 check
listen stats
    bind *:1936
    stats enable
    stats uri /haproxy?stats
    stats realm HAProxy\ Statistics
    stats auth admin:password  # 替换为您的用户名密码

重启haproxy服务后，在浏览器中通过haproxy地址（两台haproxy服务器各自IP地址）可以访问到tomcat服务，如下图所示，由于负载均衡采用的是轮询算法，所以每次刷新页面，会访问不同的tomcat服务器。

通过tomcat访问日志可以看到haproxy的IP地址访问了tomcat的web页面

bash 复制代码 
[root@web-tomcat1 logs]# tail -15 localhost_access_log.2025-04-29.txt
192.168.100.131 - - [29/Apr/2025:15:40:08 +0800] "GET /asf-logo-wide.svg HTTP/1.1" 200 27235
192.168.100.131 - - [29/Apr/2025:15:40:08 +0800] "GET /bg-middle.png HTTP/1.1" 200 1918
192.168.100.131 - - [29/Apr/2025:15:40:08 +0800] "GET /favicon.ico HTTP/1.1" 200 21630
192.168.100.131 - - [29/Apr/2025:15:41:06 +0800] "GET /tomcat.css HTTP/1.1" 200 5584
192.168.100.131 - - [29/Apr/2025:15:41:06 +0800] "GET /bg-upper.png HTTP/1.1" 200 3103
192.168.100.131 - - [29/Apr/2025:15:41:06 +0800] "GET /bg-button.png HTTP/1.1" 200 713
192.168.100.131 - - [29/Apr/2025:15:41:06 +0800] "GET /asf-logo-wide.svg HTTP/1.1" 200 27235
192.168.100.131 - - [29/Apr/2025:15:41:22 +0800] "GET / HTTP/1.1" 200 11248
192.168.100.132 - - [29/Apr/2025:15:46:33 +0800] "GET / HTTP/1.1" 200 11248
192.168.100.132 - - [29/Apr/2025:15:46:33 +0800] "GET /tomcat.svg HTTP/1.1" 200 67795
192.168.100.132 - - [29/Apr/2025:15:46:33 +0800] "GET /asf-logo-wide.svg HTTP/1.1" 200 27235
192.168.100.132 - - [29/Apr/2025:15:46:33 +0800] "GET /bg-upper.png HTTP/1.1" 200 3103
192.168.100.132 - - [29/Apr/2025:15:46:33 +0800] "GET /favicon.ico HTTP/1.1" 200 21630
192.168.100.132 - - [29/Apr/2025:15:47:45 +0800] "GET / HTTP/1.1" 200 11248
192.168.100.131 - - [29/Apr/2025:15:47:54 +0800] "GET / HTTP/1.1" 200 11248

4、keepalived安装

以下内容在lb-haproxy1，lb-haproxy2中执行。

（1）、通过命令yum install keepalived -y安装keepalived程序，安装过程如下：

bash 复制代码 
[root@lb-haproxy1 haproxy]# yum install keepalived -y
Last metadata expiration check: 1:07:06 ago on Tue 29 Apr 2025 02:54:05 PM CST.
Dependencies resolved.
========================================================================================================================================================
 Package                                         Architecture                Version                               Repository                      Size
========================================================================================================================================================
Installing:
 keepalived                                      x86_64                      2.2.8-4.el9_5                         appstream                      553 k
Installing dependencies:
 lm_sensors-libs                                 x86_64                      3.6.0-10.el9                          appstream                       41 k
 mariadb-connector-c                             x86_64                      3.2.6-1.el9_0                         appstream                      195 k
 mariadb-connector-c-config                      noarch                      3.2.6-1.el9_0                         appstream                      9.8 k
 net-snmp-agent-libs                             x86_64                      1:5.9.1-17.el9                        appstream                      693 k

Transaction Summary
========================================================================================================================================================
Install  5 Packages

Total download size: 1.5 M
Installed size: 4.4 M
Downloading Packages:
(1/5): mariadb-connector-c-config-3.2.6-1.el9_0.noarch.rpm                                                               85 kB/s | 9.8 kB     00:00    
(2/5): lm_sensors-libs-3.6.0-10.el9.x86_64.rpm                                                                          200 kB/s |  41 kB     00:00    
(3/5): mariadb-connector-c-3.2.6-1.el9_0.x86_64.rpm                                                                     643 kB/s | 195 kB     00:00    
(4/5): net-snmp-agent-libs-5.9.1-17.el9.x86_64.rpm                                                                      1.6 MB/s | 693 kB     00:00    
(5/5): keepalived-2.2.8-4.el9_5.x86_64.rpm                                                                              1.2 MB/s | 553 kB     00:00    
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                   933 kB/s | 1.5 MB     00:01     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                                                                                1/1 
  Installing       : mariadb-connector-c-config-3.2.6-1.el9_0.noarch                                                                                1/5 
  Installing       : mariadb-connector-c-3.2.6-1.el9_0.x86_64                                                                                       2/5 
  Installing       : lm_sensors-libs-3.6.0-10.el9.x86_64                                                                                            3/5 
  Installing       : net-snmp-agent-libs-1:5.9.1-17.el9.x86_64                                                                                      4/5 
  Installing       : keepalived-2.2.8-4.el9_5.x86_64                                                                                                5/5 
  Running scriptlet: keepalived-2.2.8-4.el9_5.x86_64                                                                                                5/5 
  Verifying        : lm_sensors-libs-3.6.0-10.el9.x86_64                                                                                            1/5 
  Verifying        : mariadb-connector-c-3.2.6-1.el9_0.x86_64                                                                                       2/5 
  Verifying        : mariadb-connector-c-config-3.2.6-1.el9_0.noarch                                                                                3/5 
  Verifying        : net-snmp-agent-libs-1:5.9.1-17.el9.x86_64                                                                                      4/5 
  Verifying        : keepalived-2.2.8-4.el9_5.x86_64                                                                                                5/5 

Installed:
  keepalived-2.2.8-4.el9_5.x86_64                       lm_sensors-libs-3.6.0-10.el9.x86_64             mariadb-connector-c-3.2.6-1.el9_0.x86_64      
  mariadb-connector-c-config-3.2.6-1.el9_0.noarch       net-snmp-agent-libs-1:5.9.1-17.el9.x86_64      

Complete!

安装完成后，通过命令haproxy -v查看haprox版本信息。

bash 复制代码 
[root@lb-haproxy1 haproxy]# haproxy -v
HAProxy version 2.4.22-f8e3218 2023/02/14 - https://haproxy.org/
Status: long-term supported branch - will stop receiving fixes around Q2 2026.
Known bugs: http://www.haproxy.org/bugs/bugs-2.4.22.html
Running on: Linux 5.14.0-503.14.1.el9_5.x86_64 #1 SMP PREEMPT_DYNAMIC Fri Nov 15 12:04:32 UTC 2024 x86_64

（2）、修改配置文件/etc/keepalived/keepalived.conf，使高可用对haproxy两台服务器生效。

编辑keepalived.conf加入如下内容：

bash 复制代码 
#Configuration File for keepalived
global_defs {
    router_id lb_master  #主节点标识，需唯一
    script_user root
    enable_script_security
}

vrrp_script check_haproxy {
    script "/usr/bin/killall -0 haproxy" #检查haproxy进程是否存在
    interval 2                           # 每2秒检查一次
    weight -15                           # 检查失败时降低优先级，这里注意减少的优先级要比备节点的优先级小:
    fall 2                               # require 2 failures for KO
    rise 2                               # require 2 successes for OK
}

vrrp_instance db_vip {
    state MASTER                         # 初始状态为MASTER
    interface ens33                      # 监听的网卡名称（需根据实际修改）
    virtual_router_id 51                 # 虚拟路由ID，主从必须相同
    priority 100                         # 主节点优先级(1-255) 主节点优先级(priority 100)高于备节点(priority 90)
    nopreempt
    advert_int 1                         # VRRP通告间隔(秒)
    authentication {
        auth_type PASS                   # 认证方式
        auth_pass secret456              # 密码(主从需一致)
    }
    virtual_ipaddress {
        192.168.100.135                  # 虚拟IP(VIP)，客户端访问的IP
    }
    track_script {
        check_haproxy                    # 关联健康检查脚本
    }
    notify_master "/etc/keepalived/notify.sh MASTER"  # 切换为主时执行的脚本(可选)
}

启动keepalived服务并设置开机自动启动，查看keepalived状态，为运行状态。

bash 复制代码 
[root@lb-haproxy1 keepalived]# systemctl start keepalived
[root@lb-haproxy1 keepalived]# systemctl enable keepalived
Created symlink /etc/systemd/system/multi-user.target.wants/keepalived.service → /usr/lib/systemd/system/keepalived.service.
[root@lb-haproxy1 keepalived]# systemctl status keepalived
● keepalived.service - LVS and VRRP High Availability Monitor
     Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; preset: disabled)
     Active: active (running) since Tue 2025-04-29 16:15:54 CST; 39s ago
   Main PID: 36609 (keepalived)
      Tasks: 2 (limit: 22798)
     Memory: 4.4M
        CPU: 209ms
     CGroup: /system.slice/keepalived.service
             ├─36609 /usr/sbin/keepalived --dont-fork -D
             └─36610 /usr/sbin/keepalived --dont-fork -D

Apr 29 16:16:20 lb-haproxy1 Keepalived_vrrp[36610]: (db_vip) ip address associated with VRID 51 not present in MASTER advert: 192.168.100.135
Apr 29 16:16:21 lb-haproxy1 Keepalived_vrrp[36610]: (db_vip) ip address associated with VRID 51 not present in MASTER advert: 192.168.100.135
Apr 29 16:16:27 lb-haproxy1 Keepalived_vrrp[36610]: (db_vip) ip address associated with VRID 51 not present in MASTER advert: 192.168.100.135
Apr 29 16:16:28 lb-haproxy1 Keepalived_vrrp[36610]: (db_vip) ip address associated with VRID 51 not present in MASTER advert: 192.168.100.135

当两台服务器上的keepalived服务启动后，由于lb-haproxy1服务器优先级较高，所以vip处于lb-haproxy1服务器上，通过ip addr命令可以查看到。

（4）、开启浏览器，通过VIP访问tomcat首页

通过以上步骤完成了HAproxy+keepalived+tomcat高可用负载均衡的配置

三、测试

1、服务器停机测试

（1）、关闭lb-haproxy1服务器，在lb-haproxy2服务器上查看VIP是否正常切换至该服务器上。

bash 复制代码 
[root@lb-haproxy1 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:94:e4:e9 brd ff:ff:ff:ff:ff:ff
    altname enp2s1
    inet 192.168.100.131/24 brd 192.168.100.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.100.135/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe94:e4e9/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
[root@lb-haproxy1 ~]# shutdown -h now
bash 复制代码 
[root@lb-haproxy2 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:a8:64:88 brd ff:ff:ff:ff:ff:ff
    altname enp2s1
    inet 192.168.100.132/24 brd 192.168.100.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.100.135/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fea8:6488/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

从以上可以看到VIP192.168.100.135从服务器lb-haproxy1转移到了服务器lb-haproxy2。curl 192.168.100.135可正常访问tomcat服务。当服务器lb-haproxy1重新启动后由于keepalived优先级别高于lb-haproxy2，所以VIP192.168.100.135会重新转移到服务器lb-haproxy1。

2、停止haproxy服务测试

（1）、关闭lb-haproxy1服务器上haproxy服务，在lb-haproxy2服务器上查看VIP是否正常切换至该服务器上。

bash 复制代码 
[root@lb-haproxy1 ~]# systemctl stop haproxy.service
[root@lb-haproxy1 ~]# ps -ef|grep -v grep|grep /usr/sbin/haproxy
[root@lb-haproxy1 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:94:e4:e9 brd ff:ff:ff:ff:ff:ff
    altname enp2s1
    inet 192.168.100.131/24 brd 192.168.100.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe94:e4e9/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
bash 复制代码 
[root@lb-haproxy2 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:a8:64:88 brd ff:ff:ff:ff:ff:ff
    altname enp2s1
    inet 192.168.100.132/24 brd 192.168.100.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.100.135/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fea8:6488/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

从以上可以看到VIP192.168.100.135从服务器lb-haproxy1转移到了服务器lb-haproxy2。curl 192.168.100.135可正常访问tomcat服务。当服务器lb-haproxy1重新启动haproxy服务后由于keepalived优先级别高于lb-haproxy2，所以VIP192.168.100.135会重新转移到服务器lb-haproxy1。

总结

通过以上配置实现了haproxy+keepalived+tomcat高可用负载均衡部署，负载均衡服务器也可以用nginx来替代。实践中可根据需求加以选择。

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