2 4.11 SUSE Linux system management overview System management overview Critical control files ( /etc/rc ) System Bootstrap process Head and headless management (X-Win vs. Webmin) Text based management YOU (YAST Online Update) Production options
3 4.11 RPM-based Linux SUSE is an RPM-based Linux distribution File placement is the same as Red Hat (more or less) SUSE made their own choices about what packages to use and what default to use
4 4.11 SUSE Linux customization Examples of SUSE customization include: SUSE uses postfix rather than sendmail SUSE defaults to KDE rather than Gnome SUSE wont include scripts written by Red Hat ( /sbin/service ) – making for some incompatibility
5 4.11 SUSE Linux - /etc/ The /etc directory for Red Hat & SUSE contains: *.conf files (nsswitch.cont, resolv.conf, etc) *rc files (procmailrc, bashrc, etc.) Classic configuration files (host, passwd, shadow, profile, etc) Red Hat defines the /etc directory – In the initscripts RPM SUSE defines the /etc directory – Outside the RPM system
6 4.11 SUSE Linux - /etc/rc.d, /etc/init.d SUSE has chosen a slightly different file layout for the /etc/rc.d directory. Most important is the placement and contents of /etc/rc.d. Typical Red Hat: ls -ld init.d rc.d lrwxrwxrwx 1 root root 11 Sep 14 11:56 init.d -> rc.d/init.d drwxr-xr-x 10 root root 4096 Sep 24 08:17 rc.d Typical SUSE: ls -ld init.d rc.d drwxr-xr-x 11 root root 4008 Jan 31 08:04 init.d lrwxrwxrwx 1 root root 6 Dec 15 10:53 rc.d - > init.d
7 4.11 SUSE Linux - /etc/rc.d, /etc/init.d The distinction between SUSE and Red Hat becomes important when repairing symbolic links and when writing rc start up scripts. As a result the /etc/rc.d directories look different.
8 4.11 SUSE rcn.d directories Under SUSE the rcn.d directories are inside the /etc/init.d directory:
9 4.11 Red Hat rcn.d directories Under Red Hat the rcn.d directories are inside the /etc/rc.d directory:
10 4.11 SUSE Linux - /etc/rc.d, /etc/init.d In all cases scripts that call /etc/init.d/script will work While scripts that call /etc/rc.d/init.d/script will only work in Red Hat SUSE /etc/inittab reflects the difference
11 4.11 Red Hat /etc/inittab file Red Hats /etc/inittab :
13 4.11 SUSE Linux - Startup The tasks that are run in init state 5 are almost the same in Red Hat and SUSE SUSE:
14 4.11 SUSE Linux - Startup The tasks that are run in init state 5 are almost the same in Red Hat and SUSE. Red hat:
15 4.11 SUSE Linux - Startup The astute observer will see that Red Hat uses xinet to control network interfaces, SUSE uses the inet system. Because xinet has fire-walling capability built in and inet doesnt: SUSE must rely heavily on the SUSE firewall for security SUSE administrators should set up TCP-wrappers
16 4.11 SUSE management choices This webinar is about SUSE Enterprise Server. Do you need X-Windows to manage a server? That depends! Is this your only server? Do you need to manage this machine remotely? How sophisticated are your administrators?
17 4.11 SUSE X-Windows management (1 of 2) Your management choices are limited to: X-Window based management Webmin based management Command line based management Other management systems ???
18 4.11 SUSE X-Windows management (2 of 2) X-Windows based management is best for standalone servers. Console is a PC mouse, keyboard and monitor or remote X-Window console X-Windows has many tasks that consume major system resources but are rarely used X-Windows can be used on-demand from the console: startx
19 4.11 SUSE Webmin management Webmin is a small web based administration system written in Pearl. Very useful for headless administration. Lightweight web server Uses resources sparingly Accessible via https from anywhere Not all applications can be managed from Webmin
20 4.11 SUSE command line management Command line via ssh Low overhead Accessible from anywhere Requires the most detailed knowledge of system management
21 4.11 SUSE X-Windows and YaST SUSE can be administered via X-Windows and YaST
22 4.11 Getting Webmin Webmin is an RPM or Tar package designed to run on most Unix and Linux systems. Webmin is designed for plug-in modules written in Pearl. It may be obtained from: www.Webmin.com.
23 4.11 SUSE Linux – Command line SUSE Linux can be managed from the command line. Individual command files may be edited and YaST can also be run from a telnet or ssh session
24 4.11 SUSE – Automatic maintenance (1 of 2) All Linux distributions include an automatic maintenance system Red Hat – up2date (by subscription) SUSE – YOU - YaST Online Update (by Subscription) Generic – autorpm (see www.autorpm.org)
25 4.11 SUSE – Automatic maintenance (2 of 2) Advantages of YOU - YaST Online Update – Timely updates – Security patches often issued before public announcements are made Drawbacks of YOU – Subscription basis only – Will only update SUSE RPM packages – Will NOT update RPM packages from 3rd parties You may still need to run autorpm.
26 4.11 Automatic maintenance with YOU (1 of 2) Launch YOU from YaST – really!
27 4.11 Automatic maintenance with YOU (2 of 2) Administrative choices: Update automatically or manually Update from SUSE web web site (Youll need an account) another repository: – A local directory – Via FTP – Via HTTP – Via Samba – Via NFS – Via CD or DVD
28 4.11 SUSE Linux – Headless management A large number of SUSE Linux servers are remotely managed headless systems. The problems of remote headless management are: 1.Usually cannot be managed via X-Window 2.Must be managed via ssh or Web interface 3.Only ssh and text based YaST are included with SUSE Linux Enterprise Server 8 Webmin is a good web based remote management system. Well look at Webmin shortly.