目录
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
[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
[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
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:${JRE_HOME}/lib（5）、执行java -version命令查看jdk版本，确认jdk安装完成
bash
[root@web-tomcat1 /]# java -version
java version "18.0.2.1" 2022-08-18
Java(TM) SE Runtime Environment (build 18.0.2.1+1-1)
Java HotSpot(TM) 64-Bit Server VM (build 18.0.2.1+1-1, mixed mode, sharing)2、tomcat安装
以下内容在web-tomcat1，web-tomcat2中执行，安装前关闭防火墙及selinux
（1）、将安装文件apache-tomcat-11.0.6.tar.gz拷贝到/usr/local目录下
（2）、tar -zxvf apache-tomcat-11.0.6.tar.gz，解压后usr/local目录下出现文件夹apache-tomcat-11.0.6，该文件夹内容如下：
bash
[root@test-web1 apache-tomcat-11.0.6]# ls -l
total 140
drwxr-x--- 2 root root 4096 Apr 22 10:50 bin
-rw-r----- 1 root root 24262 Apr 1 22:40 BUILDING.txt
drwx------ 3 root root 4096 Apr 24 16:50 conf
-rw-r----- 1 root root 6166 Apr 1 22:40 CONTRIBUTING.md
drwxr-x--- 2 root root 4096 Apr 22 10:50 lib
-rw-r----- 1 root root 60517 Apr 1 22:40 LICENSE
drwxr-x--- 2 root root 4096 Apr 29 10:07 logs
-rw-r----- 1 root root 2333 Apr 1 22:40 NOTICE
-rw-r----- 1 root root 3291 Apr 1 22:40 README.md
-rw-r----- 1 root root 6469 Apr 1 22:40 RELEASE-NOTES
-rw-r----- 1 root root 16109 Apr 1 22:40 RUNNING.txt
drwxr-x--- 2 root root 30 Apr 22 10:50 temp
drwxr-x--- 7 root root 81 Apr 1 22:40 webapps
drwxr-x--- 3 root root 22 Apr 22 13:27 work（3）、配置tomcat环境变量，通过vim /etc/profile命令在profile文件中加入以下内容，完成后执行source /etc/profile命令使之生效。
bash
export CATALINA_HOME=//usr/local/apache-tomcat-11.0.6
export PATH=${CATALINA_HOME}/bin:$PATH（4）、执行命令./apache-tomcat-11.0.6/bin/version.sh查看tomcat环境变量及版本信息
bash
Using CATALINA_BASE: //usr/local/apache-tomcat-11.0.6
Using CATALINA_HOME: //usr/local/apache-tomcat-11.0.6
Using CATALINA_TMPDIR: //usr/local/apache-tomcat-11.0.6/temp
Using JRE_HOME: /usr/local/jdk-18.0.2.1
Using CLASSPATH: //usr/local/apache-tomcat-11.0.6/bin/bootstrap.jar://usr/local/apache-tomcat-11.0.6/bin/tomcat-juli.jar
Using CATALINA_OPTS:
Server version: Apache Tomcat/11.0.6
Server built: Apr 1 2025 14:40:40 UTC
Server number: 11.0.6.0
OS Name: Linux
OS Version: 5.14.0-503.14.1.el9_5.x86_64
Architecture: amd64
JVM Version: 18.0.2.1+1-1
JVM Vendor: Oracle Corporation（5）、启动tomcat，进入目录/usr/local/apache-tomcat-11.0.6/bin，执行命令./startup.sh，看到如下内容说明tomcat启动成功
bash
[root@web-tomcat2 ~]# cd /usr/local/apache-tomcat-11.0.6/bin
[root@web-tomcat2 bin]# ./startup.sh
Using CATALINA_BASE: //usr/local/apache-tomcat-11.0.6
Using CATALINA_HOME: //usr/local/apache-tomcat-11.0.6
Using CATALINA_TMPDIR: //usr/local/apache-tomcat-11.0.6/temp
Using JRE_HOME: /usr/local/jdk-18.0.2.1
Using CLASSPATH: //usr/local/apache-tomcat-11.0.6/bin/bootstrap.jar://usr/local/apache-tomcat-11.0.6/bin/tomcat-juli.jar
Using CATALINA_OPTS:
Tomcat started.（6）、修改tomcat首页内容，为了后期体现出负载均衡haproxy服务访问不同的服务器，这将tomcat首页内容进行了一点修改，即修改/usr/local/apache-tomcat-11.0.6/webapps/ROOT/index.jsp页面内容。web-tomcat1服务器index.jsp页面此处修改为：
<span id="nav-home"><a href="${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
[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
[root@web-tomcat1 system]# systemctl list-units --type=service --state=running | grep tomcat
tomcat.service loaded active running Tomcat113、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
[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
[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
[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
#---------------------------------------------------------------------
# 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
[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 112484、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
[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
[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
#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
[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
[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
[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
[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
[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。