INCS Virtual Data Center Security using Linux

What is a data center? A data center is a facility used to house mission critical computer systems and associated components. It generally includes environmental controls (air conditioning, fire suppression, etc.), redundant/backup power supplies, redundant data communications connections and high security. (Wikipedia)

Data Center Physical Layout A data center can occupy one room of a building, one or more floors, or an entire building. Servers are stacked in rack cabinets Cabinets are arranged in rows with aisles in between them to allow access to both front and back of the servers

Data Center Physical Layout (cont.) Air conditioning Backup power systems Raised floors – air circulation and power wiring Overhead cable trays – data wiring Fire prevention and extinguishing systems Physical security

Why Virtual Data Center? Several servers (virtual) implemented on one physical server Reduces operation costs  AC requirements  Power requirements  Less IT personnel Easier to maintain More expensive equipment

Virtualization Environments Windows virtual environmnets:  Microsoft Virtual PC Virtual Server  VMware Linux virtual environments:  Xen  VMware

Why Linux? Linux is an Open Source operating system It is a fully 32/64 bit true multi user, multitasking, multiprocessor OS It is free There are a lot of resources available It is more secure than Windows It is supported by virtualization environments

Why Linux? (cont.) Has the X Windows GUI Coexists with other Operating Systems Runs on multiple platforms Includes the Source Code

Where to get it? There are different Linux Distributions  Fedora Core – this is the one we will use in this course  Debian  Gentoo  Slackware  Ubuntu

History Linux is created as a hobby by a student at University of Helsinki (Finland) First public version First prefabricated Linux distributions Support for non-Intel processors Linux 2.2 released Current linux version is 2.6

Linux environment Different runlevels  Runlevel 0 – halt  Runlevel 1 – single user mode  Runlevel 2 – multiuser without NFS (same as runlevel 3 when networking is not present  Runlevel 3 – full multiuser mode  Runlevel 4 – unused  Runlevel 5 – X11  Runlevel 6 - reboot

Login Usually done at:  Runlevel 3  Runlevel 5 Uses hashed passwords stored in a shadow password file WORD OF CAUTION: DO NOT LOGIN AS ROOT!!!

Work Environment Runlevel 3: console Runlevel 5: X11 environment  Window managers: GNOME KDE There are other window managers which require less space

XWindows After login is successful work can be done in consoles using linux commands

Useful Commands ls more (followed by the file name) cat (followed by the file name) cd mv mkdir rm man (followed by the command name) – see next slide

Useful Commands (cont.) Man command

Useful commands (cont.) ls -l

Useful commands (cont.) more

Editors vi emacs vim xemacs gedit

Editors vi

Linux structure

Shells Several ‘shells’ available: ksh,csh, bsh... Linux ==> bash Shell Scripts

Standard input, standard output and standard error

Important! Everything in Linux is either a file or a process

File System

Permissions Files have different permisions

Permissions (cont.) Directories are special files Links are special files ugw - rwx

Processes ps –ef shows the running processes kill – command to kill a process

Pipes and Filters Pipes and filters:  Pipes makes the output of the command to become the input for the next command  Filters read from input and write to standard output  command | filter

Print lpr –P lpq –P

More Help with Linux man – for commands