使用Inotifywait监控事件并Rsync同步变更

1. 背景

服务无法做成高可用，只能采用2个节点一主、一备（冷备）模式。为了保证主节点文件实时同步到备份节点，使用inotifywait监控主节点目录的事件，并触发rsync同步变更到备份节点。

2. 环境

服务器 VM 8C/32G/200G 2台
- 192.168.16.41 主节点
- 192.168.16.51 备份节点
操作系统 Ubuntu24.04

3. 安装依赖

bash 复制代码

# CentOS
#yum install inotify-tools rsync cron  
# Ubuntu
apt install inotify-tools rsync cron

4. 创建目录

bash 复制代码

mkdir -p /public/script/logs

5. 修改系统参数

5.1 系统参数

bash 复制代码

vim /etc/sysctl.conf

bash 复制代码

# 增加 inotify 的相关配置，解决tail: inotify 资源耗尽的错误
# 默认128
fs.inotify.max_user_instances = 12800
# 默认8192
fs.inotify.max_user_watches = 819200

5.2 加载生效

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sysctl -p

6. 备份节点

6.1 配置rsync

配置rsync

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vim /etc/rsyncd.conf

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# /etc/rsyncd: configuration file for rsync daemon mode
# See rsyncd.conf man page for more options.
# configuration example:

uid = 0
gid = 0
use chroot = no

max connections = 100
pid file = /var/run/rsyncd.pid
lock file = /var/run/rsync.lock
log file = /var/log/rsyncd/rsyncd.log 
# exclude = lost+found/
transfer logging = yes
# timeout = 900
ignore nonreadable = yes
dont compress   = *.gz *.tgz *.zip *.z *.Z *.rpm *.deb *.bz2
#include = *.gz *.tgz *.zip *.z *.Z *.bz2

[public]
        path = /public/
        # 允许写入
        read only = false
        list = yes
        #exclude = logs/ log/ *.hprof *.log log*
        auth users = rsyncuser
        secrets file = /etc/rsync.password
        # 只允许192.168.16.41连接
        hosts allow = 192.168.16.41

配置密码

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vim /etc/rsync.password

账号和密码为示例，请自定义并与主节点上的密码保持一致

bash 复制代码

rsyncuser:kxx0000

文件赋权

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ll /etc/rsync*

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# 注意密码文件必须是600
-rw-------   1 root root   18 Aug 23  2024 rsync.password
-rw-r--r--   1 root root 1204 Apr  9 15:03 rsyncd.conf

重启rsync

bash 复制代码

systemctl start rsync
systemctl enable rsync

7. 主节点

7.1 编写脚本

脚本说明
- 脚本目录：/public/script
- 脚本rsync密码文件（权限600）：/public/script/rsync_conf/rsync.password
- rsync密码需要与备份节点设置相同：注意只需要密码（不需要账号），例如：
  kxx0000
- 监控目录：/public/application
- 远程目录：application （远程rsync服务的根目录是/public，所以合并/public/application，保持与监控目录一致）
- 监控事件忽略某些文件和目录（inotifywait语法，正则匹配）：EXCLUDE_PATTERN
- rsync同步忽略某些文件和目录（rsync语法）：RSYNC_EXCLUDES
- rsync使用排它锁，保证同一时间只有一个rsync进程执行：/usr/bin/flock
- inotifywait监控事件包括: create, modify, delete, move, attrib
脚本内容（详见注释）

bash 复制代码

#!/bin/bash

#set -x

echo """
#########################################################################################################################

  Real-time sync /public/application to remote rsync server
  1. Monitor /public/application recursively using inotifywait
  2. Trigger rsync when any file/directory changes
  3. Preserve original filenames (ignore some files)
  4. Log events and delete old logs

#########################################################################################################################
"""

# Define vars
SCRIPT_HOME=/public/script
PWD_FILE=${SCRIPT_HOME}/rsync_conf/rsync.password

LOG_FILE_NAME=`basename "$0" .sh`
CURRENT_DATE=$(date +"%Y-%m-%d")
LOG_FILE=$SCRIPT_HOME/logs/${LOG_FILE_NAME}_${CURRENT_DATE}.log
LOG_RETAIN_DAY=14

# The directory to monitor
WATCH_DIR=/public/application

# Remote rsync settings
LOCAL_HOST_IP="192.168.16.41"      # 本机IP，用于远程路径组织
REMOTE_HOST_IP="192.168.16.51"
REMOTE_MODULE="public"         # rsync 模块名
REMOTE_BASE_PATH="application"

# Sync lock file to prevent concurrent rsync runs
LOCK_FILE="/tmp/rsync_public_application.lock"


# 定义inotifywait 排除的正则表达式
# ^onlyoffice/rabbitmq/ 匹配路径中包含该目录片段(注意前导 ^ 表示从监控根开始匹配)
# .*\.(swp|tmp|log|out) 匹配任意文件名，只要它以 .swp、.tmp、.log 或 .out 结尾的文件
# .*~ 匹配以 ~ 结尾的文件
EXCLUDE_PATTERN='(^onlyoffice/rabbitmq/|.*[.](swp|tmp|log|out)$|.*~$)'

# 定义rsync 排除项（相对于源目录 /public/application/）
#RSYNC_EXCLUDES="--exclude=onlyoffice/rabbitmq"
# 如果有多个排除项，可以继续添加，例如：
RSYNC_EXCLUDES="--exclude=onlyoffice/rabbitmq --exclude=*.swp --exclude=*.tmp --exclude=*.log --exclude=*.out"


###############################   start   #########################################
DATE_TIME=$(date +"%Y-%m-%d %H:%M:%S")
echo -e "### ${DATE_TIME}: $(dirname $0)/$(basename $0) starts ###" >> $LOG_FILE

# Create logs directory if not exists
if [ ! -d "$SCRIPT_HOME/logs" ]; then
   mkdir -p "$SCRIPT_HOME/logs"
   DATE_TIME=$(date +"%Y-%m-%d %H:%M:%S")
   echo -e "### ${DATE_TIME}: Directory $SCRIPT_HOME/logs has been created ###" >> $LOG_FILE
fi

# Check if watch directory exists
if [ ! -d "$WATCH_DIR" ]; then
   DATE_TIME=$(date +"%Y-%m-%d %H:%M:%S")
   echo -e "### ${DATE_TIME}: $WATCH_DIR does not exist, exit ###" >> $LOG_FILE
   exit 1
fi

# Function to perform rsync sync
do_rsync() {
    # Use flock to avoid multiple rsync processes
    (
        /usr/bin/flock -x -w 60 200 || exit 1
        # -x：请求排他锁（exclusive lock）
        # -w 60：超时等待 60 秒，退出子shell，返回1（非0）
        # 200：自定义文件描述符的编号，与200>"$LOCK_FILE" 中值保持一致，表示打开同一个文件描述符。
        DATE_TIME=$(date +"%Y-%m-%d %H:%M:%S")
        echo -e "### ${DATE_TIME}: Syncing $WATCH_DIR to remote ..." >> $LOG_FILE
        
        /usr/bin/rsync -avz --delete --password-file=${PWD_FILE} \
            $RSYNC_EXCLUDES \
            "$WATCH_DIR/" \
            "rsync://rsyncuser@${REMOTE_HOST_IP}:873/${REMOTE_MODULE}/${REMOTE_BASE_PATH}/"
        
        if [ $? -eq 0 ]; then
            DATE_TIME=$(date +"%Y-%m-%d %H:%M:%S")
            echo -e "### ${DATE_TIME}: Sync completed successfully ###" >> $LOG_FILE
        else
            DATE_TIME=$(date +"%Y-%m-%d %H:%M:%S")
            echo -e "### ${DATE_TIME}: Sync failed with error code $? ###" >> $LOG_FILE
        fi
    ) 200>"$LOCK_FILE"
}

# Delayed sync: collect events, wait for a quiet period, then sync
sync_triggered=0
delayed_sync() {
    if [ $sync_triggered -eq 0 ]; then
        sync_triggered=1
        # Wait 5 seconds to see if more events come
        sleep 5
        do_rsync
        sync_triggered=0
    fi
}

# Monitor events recursively
DATE_TIME=$(date +"%Y-%m-%d %H:%M:%S")
echo -e "### ${DATE_TIME}: Start monitoring $WATCH_DIR for changes ###" >> $LOG_FILE

# Use inotifywait to monitor events: create, modify, delete, move, attrib
/usr/bin/inotifywait -m -r --exclude "$EXCLUDE_PATTERN" -e create -e modify -e delete -e move -e attrib "$WATCH_DIR" | while read path action file; do
    # 忽略匹配模式的文件
    #case "$file" in
    #    $IGNORE_PATTERNS) continue ;;
    #esac

    DATE_TIME=$(date +"%Y-%m-%d %H:%M:%S")
    echo -e "### ${DATE_TIME}: Event: $action on $path$file ###" >> $LOG_FILE
    
    # Trigger rsync after a short delay (to combine bursts of events)
    delayed_sync &
    
    # Clean old logs periodically (once per event, but it's cheap)
    find "$SCRIPT_HOME/logs" -maxdepth 1 -mtime +$LOG_RETAIN_DAY -name "${LOG_FILE_NAME}*.log" -exec rm -rf {} \;
done

7.2 配置服务

编写服务脚本

bash 复制代码

vim rsync_backup.service

bash 复制代码

[Unit]
Description=rsync_backup.sh script
After=network.target
 
[Service]
Type=simple
PIDFile=/run/rsync_backup.pid
ExecStart=/public/script/rsync_backup.sh
ExecStop=/bin/kill -9 $MAINPID
#Restart=on-failure
Restart=always
PrivateTmp=true
#User=username
#Group=groupname
 
[Install]
WantedBy=multi-user.target

配置systemd

bash 复制代码

ln -s /public/script/rsync_backup.service /etc/systemd/system/

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systemctl daemon-reload
systemctl enable rsync_backup.service

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systemctl start rsync_backup.service 
systemctl status rsync_backup.service

bash 复制代码

● rsync_backup.service - rsync_backup.sh script
     Loaded: loaded (/etc/systemd/system/rsync_backup.service; enabled; preset: enabled)
     Active: active (running) since Thu 2026-04-09 19:51:31 CST; 23min ago
   Main PID: 2342963 (rsync_backup.sh)
      Tasks: 3 (limit: 38332)
     Memory: 1.1M (peak: 6.3M)
        CPU: 5.238s
     CGroup: /system.slice/rsync_backup.service
             ├─2342963 /bin/bash /public/script/rsync_backup.sh
             ├─2342971 /usr/bin/inotifywait -m -r --exclude "(^onlyoffice/rabbitmq/|.*[.](swp|tmp|log|out)\$|.*~\$)" -e create -e modify -e delete -e move -e attrib /public/application
             └─2342972 /bin/bash /public/script/rsync_backup.sh

......

7.3 配置重启

bash 复制代码

 crontab -e

bash 复制代码

@reboot /usr/sbin/ntpdate 192.168.5.254 > /dev/null 2>&1
0 */2 * * * /usr/sbin/ntpdate 192.168.5.254 > /dev/null 2>&1
30 */12 * * * /usr/sbin/ntpdate ntp1.aliyun.com > /dev/null 2>&1

# 每日凌晨0点，重启同步服务(rsync_backup)
0 0 * * *  systemctl restart rsync_backup.service

8 验证测试

8.1 测试忽略文件

主节点创建test.log

bash 复制代码

root@192-168-016-041:/public/application# echo "test" >> test.log
root@192-168-016-041:/public/application# ls
images  nextcloud  onlyoffice  test.log

备份节点上未同步test.log

bash 复制代码

root@192-168-016-051:/public/application# ls
images  nextcloud  onlyoffice
root@192-168-016-051:/public/application#

8.2 测试同步文件

主节点创建ok.txt

bash 复制代码

root@192-168-016-041:/public/application# echo "ok" >> ok.txt
root@192-168-016-041:/public/application# ls
images  nextcloud  ok.txt  onlyoffice  test.log

备份节点上未同步ok.txt

bash 复制代码

root@192-168-016-051:/public/application# ls
images  nextcloud  ok.txt  onlyoffice