SNA Lecture notes for APU, Lecture notes of System Programming

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System and Network Administration

Introduction & Overview

A Philosophy

• System Administration is about

• (^) Putting together a network of computers
• (^) Getting them to run some applications
• (^) Keeping them running in a dynamic world

• System Administration is as much about technology as

it is about user behaviour

• System Administration requires constant monitoring

and rapid response to problems

Challenges

• Deploy and update many machines

• Understand how services support business tasks

• Plan and implement adequate security

• Be able to fix errors and problems

• Keep track of and be able to use knowledge

• Provide comfortable environment for users

Systems & Network

Administrator Skills

• Unix/ Windows usage, installation, configuration

• Shell utilities and script programming

• C and how to use make

• Network: TCP/IP, Ethernet, hardware

• Infrastructure services: DNS, DHCP

• Shared storage: NFS , CIFS

• Directory services: LDAP, Active Directory, NIS

• User services: web, mail, database, groupware

• System tuning and accounting

• Security consciousness

Theme: Virtualization

One physical machine running a host OS, with one or

more virtual machines running a possibly different

guest operating system

Example: Hardware: blade server, 64-core Intel, 64 GB RAM OS: Red Hat Enterprise Linux Virtualization Platform: Xen Virtual machines: 32 configured as a cluster

This is the main idea

of Cloud Computing

Lower cost of ownership

• (^) labor costs
• (^) capital expenditure
• (^) power consumption
• (^) rack space

VirtualBox “Virtual Physical”

Architecture

Can we actually say that? Think of it this way: Would you expect to be able to paste what you copied if you had to change chairs to be in front of the screen, mouse, and keyboard? That is what virtual means: It acts like a real, separate machine but it runs in a window How Nice Is That ... real systems with virtual hardware (VTs) and virtual connections (wires) Real subnets with real software, virtual wiring

Philosophy:

• (^) One service, one server
• (^) Minimal server footprint – 128mb RAM, 200mb storage
  • run a 4-5 node network on a 4gb RAM Windows host
  • store everything on a 2gb thumbdrive
• (^) Open source, easy to replicate and configure
  • (Sun) VirtualBox
  • Standard linux distribution: Slackware
• (^) Tool for learning and understanding
  • curses interface, de-referenced scripts
  • buggy pre-configuration to provide good examples TinyNet: Virtualization

o Most Linux distributions have GUI configuration

utilities as well.

o These are usually just a thin layer of interpreted

code that calls the command line script

o We strike a balance with utilities that have a user

interface built on the curses libraries

This will get to be familiar VM running the mc file manager – One of the greatest linux utilities ever!

TinyNet: base configuration

Everything is built on a generic image Pre-configuration is limited to what is necessary to overcome some environmental oddities software is packaged to meet dependencies, ease installation

Getting Started

TinyNet

• Comes in two parts

 Base.iso (base image)

 Config.iso (configuration

and applications)

After installing

VirtualBox ,

create VMs!

www.my-tiny.net

1. Create one virtual machine

2. Partition the disk

3. Create a filesystem

4. Copy the OS

5. Install the bootloader

Configure Roles

Configure Mail