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Learn how to backup and log efficiently for your class assignments. Dates for last week of class, homework 7 due 5/1 and labs 7/8 due 5/3. Understand backups, logging, and troubleshooting techniques to ensure success. Explore backup mediums like hard drives and CDs, logging control by syslogs, and troubleshoot using system monitoring commands. Discover software installation methods such as source downloads and package managers like RPM and DEB for Linux systems. Enhance your knowledge for a successful class finish!
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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 • 2nd 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.priority location • 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 • Remote: @loghost
Troubleshooting • Log files in /var/ • man pages!!!! • apropos (man –k) – search man pages for matches • System monitoring commands – top, ps, etc
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
