CSE 398: System Administration

Lab #1

• 0. Become familiar with your system. Root passwords on these disks are initially set to 'lehigh' (without the quotes). Log in as root, and use passwd to change the root password to something else (use some shocking nonsense so that you don't forget it!). Use df to see what partitions are installed. Run top to see how much memory is available. Look in /etc/ to see many of the configuration files for the various services on the system.

  Use startx to get X-windows running. If you are entirely new to Linux, you may want to start by browsing some sections of Introduction to Linux (at http://www.tldp.org/LDP/intro-linux/html/). If you need some help in using bash, try the Advanced Bash-Scripting Guide (at http://www.tldp.org/LDP/abs/html/).

  Set the display resolution to something reasonable. Open a shell and run redhat-config-date to set (and permanently correct) the time and date by enabling the network time protocol, and typing ntp.cc.lehigh.edu as the time host.

  From a shell, and ssh to a sun. Use df to see what partitions are mounted on the sun you are using. Use 'whereis df' to find another version of df that presents results in essentially the same format as the one under Linux.

  Find and open a web browser, and read the details of homework #2 (but don't start it until you have finished the lab exercises below).

• 1. Edit your GRUB configuration file to include a second entry that boots your machine into single user mode. Reboot your machine using 'telinit 6' and test your new GRUB configuration.

• 2. In one shell, run top. In a second shell, use the kill command to stop the top process; resize the terminal in which top is running; then continue it. Does top receive the WINCH signal even though it wasn't running? Try quitting top now. What happens?

• 3. Scheduling a periodic job with cron.

  Log in as root. Use crontab -e to create and edit a crontab file for root. Add a crontab entry that will run the uptime command every minute for today only, and capture the output by appending to a file in /var/log. For example,

  uptime >> /var/log/uptime.log

  Then save and quit your editor. Later in the lab, take a look to see the results in this log file.

  Look in /var/log/cron to see what cron has been doing. Find an entry for mrtg. If you don't know what mrtg is, find out. Where did cron get the entry that caused it to run mrtg (exactly which file)?

  What programs are run daily?

• 4. The tool /sbin/ifconfig can be used to configure or show the status of the network interfaces. The machines in the Sandbox lab are configured with two ethernet cards.

  The first (eth0) is on a local network that just connects all machines in the lab and a KickStart/DHCP server. This DHCP server is configured to always assign the same IP address to the same machine (corresponding to the label on the machine case). The second ethernet (eth1) is on a network that is attached to a NAT gateway device to the rest of the university, and serves DHCP to configure the ethernet card.

  Running /sbin/ifconfig with no arguments generates a list of all network devices and their configurations.

  Write a short script that appends the current date/time and the results of ifconfig to the file /var/log/network-startup.log.

  Modify /etc/rc.d/rc.local to call this script. Reboot twice to make sure that each boot gets logged into this file. This log file serves as a record of which physical machine you were using at which times.