Linux System Administration Recipes A Problem-Solution Approach

More documents

Recommendations

Info

CHAPTER 4 ■ TAKING BACKUPS AND MANAGING DATA■ Note This will use ssh to backupserver as root, which may or may not be permitted on your system. Ifbackupserver isn’t on your local network, you’ll need to specify its address in full: backupserver.example.com.rsyncd must be running on backupserver. To set this up, install the relevant package for your distro(in Debian/Ubuntu it’s rsyncd), then edit /etc/default/rsync to set RSYNC_ENABLE to true, and finally run/etc/init.d/rsync start.You’ll be challenged for your ssh password (see recipe 6-3 for how to avoid this), and then rsync willlog a message to the screen that it is building the file list. This means that it is working out what files tocopy. In this case, it’ll copy all of them, because this is a first backup. Once the list is built, the copyingwill start, and using the -v switch means there’ll be a message logged to the screen for each file.Once rsync has finished, your backed-up files will be in /shared/backuphome on backupserver.example.com.■ Note rsync’s treatment of directories differs depending on whether there is a trailing slash at the end of thesource directory. The following:rsync /test/one /backupwill transfer all the files in /test/one to /backup/one. In other words, it copies the whole directory (and itscontents) by name. By contrast, the following, with the trailing slash on the source directory:rsync /test/one/ /backupwill copy all the files in /test/one to /backup. In other words, it copies only the contents, not the directory itself.Most of the time, you’ll want to use the first version because it is tidier in the sense that it keeps all the files withinthe copied directory rather than scattered into your parent backup directory.Once your first run has finished, try changing a single file and running the same command again.You’ll see that only a single file is copied this time.To avoid the ssh password challenge, you could also use mount to mount the shared backupdirectory over NFS. This script, run from homeserver, will mount the directory, run the rsync, andunmount the directory; it doesn’t use the -v (verbose) option to rsync so that output is reduced. Save itas /etc/cron.d/home-backup-script.mount -t nfs backupserver:/shared/backuphome /mntrsync -avuz /shared/home /mntumount /mnt106Download at WoweBook.Com
CHAPTER 4 ■ TAKING BACKUPS AND MANAGING DATAMake it executable with chmod u+x /etc/cron.d/home-backup-script.Finally, you need to automate this. Type crontab -e, and add this line to your crontab file:5 0 * * * /etc/cron.d/backupscriptThe numbers at the start of the crontab entry mean that this will run at five (5) minutes pastmidnight (0) every day (check the crontab man 5 page for more details).■ Note One issue with this setup is that you have only one day’s version, so if something happens to your diskovernight, the “bad” version may be written as the backup.To avoid this, you could set up a cronjob on your backup machine that runs just before the scheduled rsync andcopies your existing backup directory elsewhere. For example, this line in your crontab would do the job:5 23 * * * rsync -auz --delete /home/user/backup /home/user/backup2This runs at 11:05 p.m. daily. It would keep only one extra day’s worth of data, but that might be enough for you.You could extend this to keep more backups, but this has a high disk space penalty (although disk these days ischeap), and there quickly comes a point where you are better off relying on your tape backups.If you do have a disaster, you can now just rewrite your LDAP NFS maps (see recipe 2-13) to usebackupserver:/shared/homebackup rather than homeserver:/shared/home, and everyone can access theirfiles again (albeit with possibly up to 24 hours lost) while you fix the problem. This script will rewrite theLDAP maps for you:01 #!/usr/bin/perl -w02 use strict;03 use Net::LDAPS;0405 my $ldapserver = 'ldapserver.example.com';06 my $base = 'ou=people,dc=example,dc=com';06 my $oldhome = 'homeserver:/homedisk/';07 my $newhome = 'newserver:/newhome/';0809 my $ldap = Net::LDAPS->new( $ldapserver,10 verify => 'optional',11 cafile => '/etc/ldap/cacert.pem' ) or die $@;12 my $mesg = $ldap->bind;1314 $mesg = $ldap->search( base => $base,15 filter => "automountInformation=*$oldhome*",107Download at WoweBook.Com
Page 2:
Download at WoweBook.Com
Page 5 and 6:
Download at WoweBook.Comiii
Page 7 and 8:
Contents■About the Author .......
Page 9 and 10:
■ CONTENTS3-7. Writing a Nagios P
Page 11 and 12:
■ CONTENTS■Chapter 8: Using the
Page 13 and 14:
■ CONTENTSAbout the Author■Juli
Page 15 and 16:
■ CONTENTSAcknowledgmentsMany tha
Page 17 and 18:
■ CONTENTSIntroductionThis book i
Page 19 and 20:
■ INTRODUCTIONDownloading the Cod
Page 21 and 22:
C H A P T E R 1■ ■ ■Saving Yo
Page 23 and 24:
CHAPTER 1 ■ SAVING YOURSELF EFFOR
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
C H A P T E R 2■ ■ ■Centraliz
Page 43 and 44:
CHAPTER 2 ■ CENTRALIZING YOUR NET
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76: CHAPTER 2 ■ CENTRALIZING YOUR NET
Page 83 and 84: C H A P T E R 3■ ■ ■Monitorin
Page 85 and 86: CHAPTER 3 ■ MONITORING AND UPDATI
Page 115 and 116: C H A P T E R 4■ ■ ■Taking Ba
Page 117 and 118: CHAPTER 4 ■ TAKING BACKUPS AND MA
Page 125: CHAPTER 4 ■ TAKING BACKUPS AND MA
Page 139 and 140: C H A P T E R 5■ ■ ■Working w
Page 141 and 142: CHAPTER 5 ■ WORKING WITH FILESYST
Page 155 and 156: C H A P T E R 6■ ■ ■Securing
Page 157 and 158: CHAPTER 6 ■ SECURING YOUR SYSTEMS
Page 177 and 178:
C H A P T E R 7■ ■ ■Working w
Page 179 and 180:
CHAPTER 7 ■ WORKING WITH APACHEOn
Page 181 and 182:
CHAPTER 7 ■ WORKING WITH APACHEdi
Page 183 and 184:
CHAPTER 7 ■ WORKING WITH APACHE4.
Page 185 and 186:
CHAPTER 7 ■ WORKING WITH APACHE
Page 187 and 188:
CHAPTER 7 ■ WORKING WITH APACHEAl
Page 189 and 190:
CHAPTER 7 ■ WORKING WITH APACHE
Page 191 and 192:
C H A P T E R 8■ ■ ■Making Be
Page 193 and 194:
CHAPTER 8 ■ USING THE COMMAND LIN
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
C H A P T E R 9■ ■ ■Working w
Page 207 and 208:
CHAPTER 9 ■ WORKING WITH TEXT IN
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
C H A P T E R 10■ ■ ■Things G
Page 225 and 226:
CHAPTER 10 ■ THINGS GO IN, THINGS
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
C H A P T E R 11■ ■ ■Tracking
Page 235 and 236:
CHAPTER 11 ■ TRACKING DOWN BUGSTh
Page 237 and 238:
CHAPTER 11 ■ TRACKING DOWN BUGS01
Page 239 and 240:
CHAPTER 11 ■ TRACKING DOWN BUGS
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
CHAPTER 11 ■ TRACKING DOWN BUGSTh
Page 247 and 248:
CHAPTER 11 ■ TRACKING DOWN BUGSAn
Page 249 and 250:
CHAPTER 11 ■ TRACKING DOWN BUGS#
Page 251 and 252:
C H A P T E R 12■ ■ ■Managing
Page 253 and 254:
CHAPTER 12 ■ MANAGING TIME AND PE
Page 255 and 256:
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
APPENDIX■ ■ ■Perl TipsSee rec
Page 269 and 270:
APPENDIX ■ PERL TIPS• Date::Par
Page 271 and 272:
APPENDIX ■ PERL TIPSPerl Syntax N
Page 273 and 274:
■ ■ ■Index■Symbols$CDPATH,
Page 275 and 276:
■ INDEXenscript option (printing)
Page 277 and 278:
■ INDEX■NNagiosadding hosts to,
Page 279 and 280:
■ INDEXsyslogcentralized logging
Page 281 and 282:
Download at WoweBook.Com
show all

Linux System Administration Recipes A Problem-Solution Approach

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?