SSH Key Authentication Setup

Generate SSH keys without password protection:

ssh-keygen

Press enter to accept all defaults.

Copy the public key to the target server:

ssh-copy-id -i ~/.ssh/id_rsa.pub 192.168.1.221

Enter the password for 192.168.1.221 when prompted.

Installing Inotify Tools

Verify kernel version meets minimum requirements (2.6.13 or higher):

uname -r

Add EPEL repository and install inotify tools:

wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-6.repo
yum -y install inotify-tools
rpm -qa inotify-tools

Automated Real-time Backup Script

Create the following script to enable continuous file synchronization:

#!/bin/bash
# Script Name: syncfiles.sh
# Created: 2020-1-13

# This script implements real-time backup using rsync over SSH with inotify monitoring

LOG_PATH="/var/log/sync_activity.log"
TIMESTAMP=$(date "+%Y-%m-%d %H:%M:%S")

log_message() {
    local show_log=$1
    local message="$TIMESTAMP $2"
    
    if [ $show_log -ne 0 ]; then
        echo "$message"
        echo "$message" >> $LOG_PATH
    else
        echo "$message" >> $LOG_PATH
    fi  
}

verify_success() {
    local result=$?
    if [ ${result} -ne 0 ]; then
        log_message 1 "#[FAILURE] >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"
        log_message 1 "#[FAILURE] Error occurred: $1"
        log_message 1 "#[FAILURE] <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<"
        exit 1
    fi  
}

output_colored_text() {
    if [ $1 -eq 0 ]; then
        echo -e "\033[41;37m ${2} \033[0m"
        return 0
    fi

    if [ $1 -eq 1 ]; then
        echo -e "\033[43;37m ${2} \033[0m"
        return 0
    fi

    if [ $1 -eq 2 ]; then
        echo -e "\033[47;30m ${2} \033[0m"
        return 0
    fi
}

log_completion() {
    log_message 1 "<<<<<<<<<<<<<<<<<<<<END<<<<<<<<<<<<<<<<<<<<<<<<<<"
}

log_message 1 "<<<<<<<<<<<<<<<<<<<<Start<<<<<<<<<<<<<<<<<<<<<<<<<<"

# Configuration parameters
TARGET_SERVER=192.168.1.221
SOURCE_DIR=/root/aa_inotify
DESTINATION_DIR=/test_inotify

# Initial sync with delete option
echo "Starting initial synchronization..."
rsync -Rraz --delete -e ssh $SOURCE_DIR root@${TARGET_SERVER}:${DESTINATION_DIR}

# Monitor directory changes and sync in real-time
/usr/bin/inotifywait -mrq --format '%w%f' -e create,close_write,delete $SOURCE_DIR | while read filepath
do
    rsync -Rraz --delete -e ssh ${filepath} root@${TARGET_SERVER}:${DESTINATION_DIR}
done

log_completion

To enable automatic startup, add the script to /etc/rc.local:

# Add this line before the exit statement
/path/to/syncfiles.sh &

Ensure the script has execute permissions:

chmod +x /path/to/syncfiles.sh

The system will now manitain real-time synchronization between the source and destination directories, automatically propagating file changes as they occur.