Build rsync services in Linux

1.rsync Introduction

    rsync是类unix系统下的数据镜像备份工具，从软件的命名上就可以看出来了——remote sync。rsync是Linux系统下的文件同步和数据传输工具，它采用“rsync”算法，可以将一个客户机和远程文件服务器之间的文件同步，也可以在本地系统中将数据从一个分区备份到另一个分区上。如果rsync在备份过程中出现了数据传输中断，恢复后可以继续传输不一致的部分。rsync可以执行完整备份或增量备份。它的主要特点有：    1.可以镜像保存整个目录树和文件系统；    2.可以很容易做到保持原来文件的权限、时间、软硬链接；无须特殊权限即可安装；    3.可以增量同步数据，文件传输效率高，因而同步时间短；    4.可以使用rcp、ssh等方式来传输文件，当然也可以通过直接的socket连接；    5.支持匿名传输，以方便进行网站镜象等；    6.加密传输数据，保证了数据的安全性；

Advantages and disadvantages of 2.rsync

与传统的cp、tar备份方式对比，rsync具有安全性高、备份迅速、支持增量备份等优点，通过rsync可以解决对实时性要求不高的数据备份需求，例如，定期地备份文件服务器数据到远端服务器，对本地磁盘定期进行数据镜像等。但是随着系统规模的不断扩大，rsync的缺点逐渐被暴露了出来。首先，rsync做数据同步时，需要扫描所有文件后进行对比，然后进行差量传输。如果文件很大，扫面文件是非常耗时的，而且发生变化的文件往往是很少一部分，因此rsync是非常低效的方式。其次，rsync不能实时监测、同步数据，虽然它可以通过Linux守护进程的方式触发同步，但是两次触发动作一定会有时间差，可能导致服务器端和客户端数据出现不一致

SSH authentication protocol for 3.rsync

        rsync命令来同步系统文件之前要先登入 remote主机认证，认证过程中用到的协议有2种：        ssh协议        rsync协议    rsync server 端不用启动rsync的daemon进程，只要获取remote host 的用户名和密码就可以直接rsync同步文件    rsync server端因为不用启动daemon进程，所以也不用配置文件      /etc/rsyncd.cof            ssh认证协议跟scp的原理是一样的，如果在同步过程中不想输入密码就用 ssh-keygen  -t  rsa 打通通道            //这种方式默认是省略了 -e  ssh 的下面等价：            rsync -avz /SRC -e ssh [email protected]:/DEST                      -a     //文件宿主变化，时间戳不变                      -z     //压缩数据传输            //当遇到要修改端口的时候，我们可以用：            rsync -avz /SRC -e "ssh -p2222" [email protected]:/DEST            //修改了ssh 协议的端口，默认是22

4.rsync Command common options:

      -a, --archive                            //归档      -v,   --verbose                       //啰嗦模式      -q, --quiet                             //静默模式      -r, --recursive                        //递归      -p, --perms                           //保持原有的权限属性      -z, --compress                     //在传输时压缩，节省带宽，加快传输速度

5. Example Demo:

环境说明

Server Type	IP Address
Source Server	192.168.209.12
Target server	192.168.209.13

* Demand * * *
Synchronize the/etc directory on the original server to the/tmp/of the target server in real time

 On the target server, do the following: *****************rsync+inotify****************//target server-side operations first shut down the firewall [[email protected] ~]# Yum ins   Tall-y rsync [[email protected] ~]# cat >>/etc/rsyncd.conf << EOF > log file =/var/log/rsync.log > pidfile =/var/run/rsyncd.pid > Lock file =/var/run/rsync.lock > Secrets file =/etc/rsync.pass > ; [Etc_from_client] > Path =/tmp/> comment = Sync etc from Client > uid = root > gid = root > Por   t = 873 > Ignore errors > Use chroot = no > Read only = no > list = no > Max connections = 200  > timeout = > Auth users = admin >eof//Create user authentication file [[email protected] ~]# echo ' admin:123456 ' > /etc/rsync.pass [[email protected] ~]# cat/etc/rsync.passadmin:123456//Set file permissions [[email protected] ~]# chmod 600/etc/rsync* [[email protected] ~]# ll/etc/rsync*-RW-------. 1 root root 787 August 15:13/etc/rsyncd.conf-rw-------1 ROot Root 13 August 15:14/etc/rsync.pass//Start rsync service and set boot self-boot [[email protected] ~]# systemctl start RSYNCD [[E Mail protected] ~]# systemctl enable RSYNCD [[email protected] ~]# ss-antl::: 873 Port # # # #源服务器  End first off firewall//configure Yum source [[[email protected] ~]# cd/etc/yum.repos.d/[[email protected] yum.repos.d]# wget Http://mirrors.163.com/.help/CentOS7-Base-163.repo [[email protected] ~]# sed-i ' s/\ $re Leasever/7/g '/etc/yum.repos.d/centos7-ba Se-163.repo [[email protected] ~]# sed-i ' s/^enabled=.*/enabled=1/g '/ Etc/yum.repos.d/cen Tos7-base-163.repo [[email protected] ~]# yum install-y epel-release [[Email protec Ted] ~]# Yum install-y update--skip-broken//install Rsync server, need to install, do not start, do not need to configure [[email protected] ~]# yum install-y r Sync//create authentication password file [[[email protected] ~]# echo ' 123456 ' >/etc/rsync.pass [[email protected] ~]# Cat/etc/rsy Nc.pass 123456//Set file rightsLimit, only set the file owner to have read, write permission can be [[email protected] ~]# chmod 600/etc/rsync.pass [[email protected] ~]# LL/ETC/RSYNC.P ASS-RW-------. 1 root root 7 August 16:05/etc/rsync.pass//Create a test directory on the source server and run the command on the original server [[email protected] ~]# mkdir-pv/root/etc /test [[email protected] ~]# RSYNC-AVH--port 873--progress--delete/root/etc/[email protected]::etc_from_ After client--password-file=/etc/rsync.pass//This step, there is a test directory under the/TMP directory on the clients, indicating that the data synchronization is successful//check whether the server kernel supports inotify[[email  Protected] ~]# ll/proc/sys/fs/inotify///installation inotify-tools[[email protected] ~]# yum install-y make gcc gcc-c++[[ Email protected] ~]# Yum install-y inotify-tools//Write synchronization script [[email protected] ~]# mkdir/scripts[[email  Protected] ~]# touch/scripts/inotify.sh[[email protected] ~]# chmod 755/scripts/inotify.sh[[email  Protected] ~]# ll/scripts/inotify.sh-rwxr-xr-x. 1 root root 0 August 16:27/scripts/inotify.sh[[email protected] ~]# vim/scripts/inotify.sh#!/bin/bash host=192.168.209.13 src=/etc des=etc_from_client password=/etc/rsync.pass user=admin inotifywait=/usr/bin/inotifywait $ Inotifywait-mrq--timefmt '%y%m%d%h:%m '--format '%T%w%f%e '-E modify,delete,create,attrib $src | While read files;d o rsync-avzp--delete--timeout=100--password-file=${password} $src [email protected] $host:: $d Es echo "${files} was rsynced" >>/tmp/rsync.log 2>&1done//startup script [[email protected] ~]# nohup bash/ scripts/inotify.sh &[2] 3351[[email protected] ~]# nohup: Ignores input and appends output to "nohup.ou[[email protected" ~]# PS -ef|grep inotify//generate a new file on the source server [[email protected] ~]# mkdir/etc/lanzhiyong[[email protected] ~]# Echo ' I Love China ' >/etc/lanzhiyong/lan//view inotify generated log [[email protected] ~]# tail/tmp/rsync.log//Setup script boot automatically [[ Email protected] ~]# chmod +x/etc/rc.d/rc.local [[email protected] ~]# ll/etc/rc.d//rc.local [[email  Protected] ~]# echo ' nohup/bin/bash/scripts/inotify.sh ' >>/etc/rc.d/rc.local[[email protected] ~]# tail/etc/rc.d/rc.local The last example demonstrates validation: on the target server [[email protected] ~] #cd/tmp[[email  Protected] ~] #cd/etc[[email protected] ~] #cd lanzhiyong[[email protected] ~] #cat LanI love China

Setting up rsync services in Linux in detail