Automatically Backup using rsync & crontab.

Automatically Backup using rsync & crontab.

By: Kashif Aziz Awan
kashif_khb@yahoo.com
www.kashifaziz.co.cc
November 13, 2009



Purpose:

It is used for backup from one computer to other computer automatically/scheduled.


This document has three parts:

1- Password less Authentication with ssh

2- rsync configuration

3-crontab configuration


Assumptions:-
system 1:- 172.16.0.11 [client] to whom we want to backup it.
system 2:- 172.16.0.12 [server] to where we want to backup.

1- Password less Authentication with ssh
:

check ssh service at both systems, server and client.

[root@172.16.0.11 ~]# service ssh status

If working, well if not then first install and start it.

Now check that ssh working by ssh from client to server.

[root@172.16.0.11 ~]# ssh 172.16.0.12

It prompt for passwd....ok it works.

Now we need password less ssh from client to server:
do, On client 172.16.0.11
generate ssh shared key

[root@172.16.0.11 ~]# cd /root/.ssh/
[root@172.16.0.11 ~]# ssh-keygen -t rsa

Generating public/private rsa key pair.

Enter file in which to save the key (/root/.ssh/id_rsa):

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /root/.ssh/id_rsa.

Your public key has been saved in /root/.ssh/id_rsa.pub.

The key fingerprint is:

42:8c:96:45:7d:06:38:38:2d:6e:d5:b6:43:28:6e:53 root@172.16.0.11

[root@172.16.0.11 ~]#


just hit (enter key) til back at the prompt

it will create two files at location:
/root/.ssh/ i) id_rsa ii) id_rsa.pub
now copy the file, named id_rsa.pub from client to server at same location:

do, On Server 172.16.0.12

[root@172.16.0.12 ~]# cd /root/.ssh
[root@172.16.0.12 ~]# cat /root/.ssh/id_rsa.pub >> authorized_keys

If authorized_keys file not exist just create and do it again...

[root@172.16.0.11 ~]# chmod -R 700 /root/.ssh/*

Done!

Now try to ssh from client to server:

[root@172.16.0.11 ~]# ssh 172.16.0.12

It work password less.

2- rsync configuration
:

at both systems package “rsync” must be installed..

[root@172.16.0.12 ~]# yum install rsync


[root@172.16.0.11 ~]# rsync -azvv -e ssh /home/folders root@172.16.0.12:/home/
This will copy /home/folders from client 0.11 to server 0.12:/home/folders.

-a = archive

-v= Verbose

-z = compress form

--delete= delete folder other than match with client 0.11

3-crontab configuration


Now we need it scheduled/automatically so we need crond serves for this:-
do, On client 172.16.0.11

[root@172.16.0.11 ~]# service crond status

If working then good if not first install it by:-

[root@172.16.0.11 ~]# yum install vixie-cron

Default file:-

[root@172.16.0.11 ~]# vi /etc/crontab
SHELL=/bin/bash

PATH=/sbin:/bin:/usr/sbin:/usr/bin

MAILTO=root

HOME=/



# run-parts

01 * * * * root run-parts /etc/cron.hourly

02 4 * * * root run-parts /etc/cron.daily

22 4 * * 0 root run-parts /etc/cron.weekly

42 4 1 * * root run-parts /etc/cron.monthly

~
~
Type :quit<Enter> to exit Vim


1st * represent minutes 0-59

2nd * represent hour 0-23

3rd * represent day 1-31

4th * represent month 1-12

5th * represent week 0-6 o represent sunday and 1 represent monday

and so on
if you want to start rsync every 3 minutes then type these script in this.


*/3 * * * * root rsync -azvv -e ssh /home/folders root@172.16.0.12:/home/

here */3 represent that after 3 minutes this script run.

OPTIONAL:-

We can run a script file for rsync and bunzip using cronjob

for examlple create a file as

vi /etc/cron.hourly/hourly

and give permission to this file as

Chmod 755 -R /etc/cron.hourly/hourly

and add a script in this file as below:



tar -cvjf /path/zipdirectoryname$(date +%y%m%d).tar.bz2 /path/source directory

example

tar -cvjf /home/folders$(date +%y%m%d).tar.bz2 /home/folders

rsync -avzu --delete -e ssh /home/aurangzeb$(date +%y%m%d).tar.bz2 root@172.16.0.12:/home/folders && rm /home/aurangzeb$(date +%y%m%d).tar.bz2



In this file first it create a folder /home/folders in bunzip form with the latest date and then using rsync copy the folder on remote system and remove the zip file from the local pc.


Kind Regards:-
Kashif Azeez Awan
www.kashifaziz.co.cc
http://kashifaziz.4shared.com
www.apnacns.co.cc