Backups, Logging, Troubleshooting

Dates for Last Week of Class Homework 7 – Due Tuesday 5/1 by midnight Labs 7 & 8 – 8 is extra credit – Due Thursday 5/3 by midnight – No Late ones accepted Final – Thursday 5/3 – 6 – 9:30 in classroom – open [book|notes|computer] – will need working VM

Backups What to backup? How often? Where? Don’t forget to test restores!!!

Backup Medium 2 nd Hard Drive CDs, DVDs, Flash Drives Tape Another server Online

Backup Utilities tar cpio dump/restore zip/unzip dd really, really expensive commercial ones

Logs Controlled by 2 daemons –syslog – general logging –klogd – kernel messages

Syslog Controlled by /etc/syslog.conf: # Log anything except mail of level info or higher. # Don't log private authentication messages! *.info;mail.none;authpriv.none;cron.none /var/log/messages # The authpriv file has restricted access. authpriv.* /var/log/secure # Log all the mail messages in one place. mail.* -/var/log/maillog # Log cron stuff cron.* /var/log/cron

Syslog Format Basic syntax: codeword.prioritylocation Example: cron.* /var/log/cron

Syslog Codewords auth – message from a user authentication program this used to be called security auth-priv – private authentication program daemon – any daemon not explicitly listed will generate a message under this category kern – kernel messages through klogd syslog – messages about the logging process itself user – messages from application software started by a user local0 through local7 – messages generated by Linux where the level is established by the Linux vendor local7 for instance pertains to boot messages cron, lpr, mail, news – self explanatory

Syslog Priorities From lowest to highest: –none - no priority –debug - log debugging messages used by programmers or testers of the software –info - log informational messages about what the program is doing –notice - noteworthy events –warning - potential problem events –err – errors –crit - critical error messages that will likely cause the program to terminate –alert - like crit except that the error can impact other programs –emerg - problems serious enough to potentially crash the entire OS

Syslog location File: /some/path/to/file

Troubleshooting Log files in /var/ man pages!!!! apropos (man –k) – search man pages for matches System monitoring commands – top, ps, etc

Software Installation

How to install? Source –Download.tar.gz, extract, make, make install Packages (2 biggest for Linux)‏ –RPM – Redhat Package Manager –DEB – Debian Packages Commercial Unix –bff for AIX – Backup File Format –dstream for Solaris - shar

Package Managers CentOS Specific –rpm (command line)‏ –yum (command line)‏ –pirut (Graphical front-end to yum)‏ “Applications” → “Add/Remove Software”

yum yum – Yellowdog Updater Modified –Used for installing new software –Used for removing old software –Used for updating current software

Make Used to build software from source all: scheduler scheduler: scheduler.o g++ scheduler.o -o scheduler scheduler.o: scheduler.C g++ -c scheduler.C clean: rm -rf *o scheduler install: scheduler mkdir -p /usr/local/bin cp scheduler /usr/local/bin