Linux System Administration Recipes A Problem-Solution Approach

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CHAPTER 4 ■ TAKING BACKUPS AND MANAGING DATATo specify which key the rsync command should use, run the following:rsync -avuz -e "ssh -i /home/user/.ssh/rsync" /test \user@offsite.example.com:/home/user/backupThis line must match the command you put in the previous ~/.ssh/authorized_keys2 file, oroffsite.example.com will refuse your access. You should see output indicating rsync connecting via sshwithout a password prompt, building the filelist, and then updating with any changes.4-8. Creating an Off-Site Backup via E-mailAnother option for the off-site backup of a limited number of files is to use e-mail. In particular, at thetime of this writing, Gmail offered 7GB of storage for free and was prepared to sell you further space; youmay even have access to your own off-site e-mail server. You can set up a Perl script to e-mail a given setof files to your Gmail account and then run it automatically every night with cron.■ Note There are size limitations with this! Most e-mail servers will limit the size of mail message that they areprepared to accept, because very large e-mails are a nuisance and can cause network slowdown. So, this methodis really useful only for small numbers of smallish files. Text files tend to be small, so it may be reasonable toe-mail yourself a backup of your script directories or even of the dump of your wiki as described in recipe 4-3.It’s not a good solution for an entire home directory, however.The Perl modules Net::SMTP, File::Find, Mime::Lite, Archive::Tar, and IO::Zlib are required forthis script. In Debian, the first two of these are a default part of the regular Perl install; install the otherswith the following:sudo apt-get install libmime-lite-perl libarchive-tar-perl libio-zlib-perlAlternatively, you can install them using CPAN (see the appendix for notes on CPAN and Perlmodules):perl -MCPAN -e "install Net::SMTP"perl -MCPAN -e "install File::Find"perl -MCPAN -e "install Mime::Lite"perl -MCPAN -e "install Archive::Tar"The script looks like this:01 #!/usr/bin/perl -w0203 use strict;04 use Archive::Tar;05 use File::Find;110Download at WoweBook.Com
CHAPTER 4 ■ TAKING BACKUPS AND MANAGING DATA06 use MIME::Lite;07 use Net::SMTP;0809 sub sendmail();10 sub wanted();1112 my $email = 'my.name@gmail.com';13 my $from = 'my.address@example.com';14 my $smtpserver = "smtp.example.com";15 my @archive_list;16 my $backup_dir = "/home/jkemp/personal/";17 my $tarfile = "/home/jkemp/gmailtar.tgz";1819 find ( \&wanted, $backup_dir );20 Archive::Tar->create_archive($tarfile, "1", @archive_list);21 sendmail();2223 sub wanted() {24 return unless -f $File::Find::name;25 push @archive_list, $File::Find::name;26 }2728 sub sendmail() {29 my $msg = MIME::Lite->new(To => $email,30 From => $from,31 Subject => "Backup email",32 Type => "multipart/mixed");33 $msg->attach(Type => "application/gzip",34 Path => $tarfile,35 Filename => "gmailtar.tgz");36 $msg->send('smtp', $smtpserver);37 }Before you run it, change the permissions:chmod u+x gmail.plLines 04–10 import the other required modules and declare the subroutines that come later in thecode. Lines 12–16 set your variables up, which is another good coding practice.Line 18 uses the find command from File::Find to recurse over the directory you want to back up(here /home/jkemp/personal/). It calls the wanted subroutine (defined in lines 22–25) to check that thename that has been passed in (here /home/jkemp/personal corresponds to an existing file and, if so, addsthe file to the array of files to be archived).■ Note When using subroutines, you must either define them before they are first used or declare them first anddefine them at the end. I’ve done the latter here.111Download at WoweBook.Com
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Contents■About the Author .......
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■ CONTENTS3-7. Writing a Nagios P
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■ CONTENTS■Chapter 8: Using the
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■ CONTENTSAbout the Author■Juli
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■ CONTENTSAcknowledgmentsMany tha
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■ CONTENTSIntroductionThis book i
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■ INTRODUCTIONDownloading the Cod
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C H A P T E R 1■ ■ ■Saving Yo
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CHAPTER 1 ■ SAVING YOURSELF EFFOR
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C H A P T E R 2■ ■ ■Centraliz
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CHAPTER 2 ■ CENTRALIZING YOUR NET
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CHAPTER 7 ■ WORKING WITH APACHEdi
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CHAPTER 7 ■ WORKING WITH APACHE4.
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CHAPTER 7 ■ WORKING WITH APACHE
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CHAPTER 7 ■ WORKING WITH APACHEAl
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CHAPTER 7 ■ WORKING WITH APACHE
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C H A P T E R 8■ ■ ■Making Be
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CHAPTER 8 ■ USING THE COMMAND LIN
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C H A P T E R 9■ ■ ■Working w
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CHAPTER 9 ■ WORKING WITH TEXT IN
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C H A P T E R 10■ ■ ■Things G
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CHAPTER 10 ■ THINGS GO IN, THINGS
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C H A P T E R 11■ ■ ■Tracking
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CHAPTER 11 ■ TRACKING DOWN BUGSTh
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CHAPTER 11 ■ TRACKING DOWN BUGS01
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CHAPTER 11 ■ TRACKING DOWN BUGS
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CHAPTER 11 ■ TRACKING DOWN BUGSTh
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CHAPTER 11 ■ TRACKING DOWN BUGSAn
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CHAPTER 11 ■ TRACKING DOWN BUGS#
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C H A P T E R 12■ ■ ■Managing
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CHAPTER 12 ■ MANAGING TIME AND PE
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APPENDIX■ ■ ■Perl TipsSee rec
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APPENDIX ■ PERL TIPS• Date::Par
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APPENDIX ■ PERL TIPSPerl Syntax N
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■ ■ ■Index■Symbols$CDPATH,
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■ INDEXenscript option (printing)
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■ INDEX■NNagiosadding hosts to,
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■ INDEXsyslogcentralized logging
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