CP 211: Introduction to Linux/Unix
Systems
Lecture 1: Introduction to System Administration
Course Description
This course is designed for students to build their
theoretical and practical skills in systems
administration on Unix/Linux to a level where they can
configure and manage workstations.
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This course will be handled by two instructors:
Course Objective
The main objective of this course is to introduce
students to the task of system administration, looking
after and maintaining linux/unix based systems.
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Learning Outcomes
Upon completion of this course, students should be
able:
– Perform
systems
installation of UNIX or Linux operating
– Perform
basic configuration and maintenance of
UNIX/Linux systems
– Write
simple shell scripts
Mode of Delivery
40 Lecture hours + 20, tutorial/seminar hours 10
Assignment hours, 20 independent study hours and 10
practical training hours.
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Course Contents
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Introduction to System Administration, Roles and responsibilities
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Background of LINUX, variation of LINUX
Managing Users: Group, Individual, Process: Adding, Deleting,
Modifying User Attributes, Password, The Login Process,/etc/profile and
.profile.
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File System: Structure, File and Directory, Shared File & Directory,
Process: create, delete, rename file and directory, vi Editor
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Shell Scripting: Shell Programming, Example scripting, Advanced
Scripting
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Backup & Recovery: Backup Strategies, Essential Tools, tar, cpio and
dump command, network Backup Strategies
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Security
Recommended References/Textbooks:
Nicholas Well, The Complete Guide to Linux System
Administration, Thomas Course Technology, 2005
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Overview of Operating Systems
What is an Operating System?
An Operating System (OS) is a program that acts
as an intermediary between the user and the
hardware
Operating system goals:
• Execute user programs and make solving user
problems easier
• Make the computer system convenient to use
• Use the computer hardware in an efficient manner
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Operating System Services
1. Program execution
The system must be able to load a program into memory
and to run that program, end execution, either normally or
abnormally (indicating error)
2. I/O Operations
Each program requires an input and produces output. This
involves the use of I/O. The operating systems hides the
user the details of underlying hardware for the I/O. All the
user sees is that the I/O has been performed without any
details. So the operating system by providing I/O makes it
convenient for the users to run programs.
Operating System Services
3. File System Manipulation
The output of a program may need to be written into new
files. The user does not have to worry about secondary
storage management. User gives a command for reading
or writing to a file and sees his task accomplished. Thus
operating system makes it easier for user programs to
accomplish their task.
4. Communications
Processes may exchange information, on the same
computer or between computers over a network.
Operating System Services
5. Error detection –
Os needs to be constantly aware of possible errors
• May occur in the CPU and memory hardware, in I/O
devices, in user program
• For each type of error, OS should take the appropriate
action to ensure correct and consistent computing
• Debugging facilities can greatly enhance the user’s and
programmer’s abilities to efficiently use the system
6. Resource allocation –
When multiple users or multiple jobs running concurrently,
resources must be allocated to each of them
• Many types of resources - CPU cycles, main memory, file
storage, I/O devices.
Operating System Services
7. Protection and security –
The owners of information stored in a multiuser or networked
computer system may want to control use of that information,
concurrent processes should not interfere with each other
• Protection involves ensuring that all access to system resources is controlled
• Security of the system from outsiders requires user authentication, extends to
defending external I/O devices from invalid access attempts
Modern OS Architectures - Android
Modern OS Architectures – Windows 10
Modern OS Architectures – MacOS
Market Share
Market Share
Market Share
Public servers on the Internet
Market Share
Supercomputers
What is system administration?
In computer technology, a set of functions that
provides support services, ensures reliable operations,
promotes efficient use of the system, and ensures that
prescribed service-quality objectives are met.
➔
It plays a vital role when a system is accessed by
multiple users.
➔
In essence, system administration is used to ascertain
that there is little to complain about the system’s
performance or service availability.
➔
Systems Administration
The subject matter of systems administration includes
computer systems and the ways people use them in an
organization.
➔This entails a knowledge of operating systems and
applications, as well as hardware and software
troubleshooting, but also knowledge of the purposes
for which people in the organization use the computers.
➔
A system Administrator
A job position of engineers involved in computer
systems. They are the people responsible for running
the system, or running some aspect of it.
➔
A system administrator, or sysadmin , is responsible
for the installation, configuration, monitoring and
assurance of an IT infrastructure.
➔
This infrastructure is usually composed of computer
networks with hardware, such as switches, routers,
servers and workstations, and software running on
them, such as firewalls, databases and web servers.
➔
Types of Administrators
In a larger company, the following administrators may
all be separate positions within a computer support or
Information Services (IS) department. In a smaller
group they may be shared by a few sysadmins, or even
a single person.
Database Administrator
●Network Administrator
●Security Administrator
●Web Administrator
●Technical support
●Computer operator
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Types of Administrators
Types of Administrators
A database administrator (DBA) maintains a database
system, and is responsible for the integrity of the data
and the efficiency and performance of the system.
A network administrator maintains network
infrastructure such as switches and routers, and
diagnoses problems with these or with the behavior of
network-attached computers.
A security administrator is a specialist in computer and
network security, including the administration of security
devices such as firewalls, as well as consulting on
general security measures.
Types of Administrators
A web administrator maintains web server services (such as IIS
or Apache) that allow for internal or external access to web sites.
Tasks include managing multiple sites, administering security, and
configuring necessary components and software. Responsibilities
may also include software change management.
Technical support staff respond to individual users' difficulties
with computer systems, provide instructions and sometimes
training, and diagnose and solve common problems.
A computer operator performs routine maintenance and upkeep,
such as changing backup tapes or replacing failed drives in a RAID
array. Such tasks usually require physical presence in the room
with the computer; and while less skilled than sysadmin tasks
require a similar level of trust, since the operator has access to
possibly sensitive data.
Challenges of system administration
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Designing a network which is logical and efficient.
Deploying large numbers of machines which can be
easily upgraded later.
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Deciding what services are needed.
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Planning and implementing adequate security.
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Providing a comfortable environment for users.
Developing ways of fixing errors and problems which
occur.
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Keeping track of and understanding how to use the
enormous amount of knowledge which increases every
year.
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The meta principles of system
administration
Principle 1 (Policy is the foundation).
System administration begins with a policy – a
decision about what we want and what should be, in
relation to what we can afford.
Principle 2 (Predictability).
The highest level aim in system administration is to
work towards a predictable system. Predictability has
limits. It is the basis of reliability, hence trust and
therefore security.
The meta principles of system
administration
Principle 3 (Scalability).
Scalable systems are those that grow in accordance
with policy; i.e. they continue to function predictably,
even as they increase in size.
Essential duties of a system
administrator
Controlling access: creates accounts for new
users, removes the accounts of inactive users,
and handles all the account-related issues that
come up in between (e.g., forgotten passwords
and lost key pairs)
Adding hardware: Administrators who work with
physical hardware must install it and configure it to
be recognized by the operating system
Essential duties of a system
administrator
Automating tasks: Using tools to automate
repetitive and time-consuming tasks increases
your efficiency, reduces the likelihood of errors
caused by humans, and improves your ability to
respond rapidly to changing requirements.
Overseeing backups: Backing up data and
restoring it successfully when required are
important administrative tasks
Essential duties of a system
administrator
Installing and upgrading software: Software must
be selected, installed, and configured, often on a
variety of operating systems. As patches and
security updates are released, they must be
tested, reviewed, and incorporated into the local
environment without endangering the stability of
production systems.
Essential duties of a system
administrator
Monitoring: Working around a problem is usually faster
than taking the time to document and report it, and users
internal to an organization often follow the path of least
resistance. External users are more likely to voice their
complaints publicly than to open a support inquiry
Troubleshooting: Networked systems fail in unexpected
and sometimes spectacular fashion. It’s the
administrator’s job to play mechanic by diagnosing
problems and calling in subject-matter experts as
needed. Finding the source of a problem is often more
challenging than resolving it.
Essential duties of a system
administrator
Maintaining local documentation:
Administrators choose vendors, write scripts,
deploy software, and make many other decisions
that may not be immediately obvious or intuitive to
others. Thorough and accurate documentation is a
blessing for team members who would otherwise
need to reverse-engineer a system to resolve
problems in the middle of the night.
Essential duties of a system
administrator
Tuning performance: UNIX and Linux are general
purpose operating systems that are well suited to
almost any conceivable computing task.
Administrators can tailor systems for optimal
performance in accord with the needs of users,
the available infrastructure, and the services the
systems provide
Essential duties of a system
administrator
Developing site policies: For legal and compliance
reasons, most sites need policies that govern the
accept able use of computer systems, the
management and retention of data, the privacy
and security of networks and systems, and other
areas of regulatory interest.
System administrators often help organizations
develop sensible policies that meet the letter and
intent of the law and yet still promote progress and
productivity.
Essential duties of a system
administrator
Working with vendors: Most sites rely on third
parties to provide a variety of ancillary services
and products related to their computing
infrastructure.
Administrators may be tasked with selecting
vendors, assisting with contract negotiations, and
implementing solutions once the paperwork has
been completed.
Essential duties of a system
administrator
Fire fighting: Although helping other people with
their various problems is rarely included in a
system administrator’s job description, these tasks
claim a measurable portion of most administrators’
workdays.
System administrators are bombarded with
problems ranging from “It worked yesterday and
now it doesn’t! What did you change?” to “I spilled
coffee on my keyboard! Should I pour water on it
to wash it out?”
Can you summarize the duties of
Systems Administrators into two basic
jobs/duties?
Required Skills and Qualities
Hard skills
●Must be an expert hardware and software tinkerer
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Comfortable in multiple Oses
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Install and configure server and client software
Know how networks work and how computers
communicate
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Script programming
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Leveraging the Internet for information
Required Skills
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Hard Skills
–Linux,
Windows, OS X, Solaris, Perl, PHP, JavaScript, HTML, XML,
CSS, AJAX, Active Directory, SQL, Amanda, TCP/IP, HTTP, SMTP,
IMAP, POP, SVN, CVS, LDAP, DNS, DHCP, SSH, SFTP, FTP, SSL,
Java, Apache, Tomcat, MySQL, PostgreSQL, RRT, Cricket, Nagios,
Samba, SMB, BOOTP, IPMI, PXE, Python, sh, bash, csh, MPI, SGE,
Globus, Grid, Cluster, CUPS, LPR, DFS, EXT3, Reiser, XFS, JFS, Squid,
iptables, IBRIX, Infiniband, Ethernet, DVI, USB, PCI, PCI-X, PCIe,
DIMM, CMOS, BIOS, ISO, IIS, Postfix, sendmail, dovecot, courierimap, scp, df, du, top, uptime, find, tar, tail, less, grep, ls, vi, emacs, ps,
man, which, crontab, cp, dump, more, ruby, c, c++, sed, awk, proc,
postscript, pdf, latex, drupal, plone, modprobe, regedit, group policy,
ping, route……….
The point is, you obviously can’t learn all of these, so
focus on getting a good foundation and being able to
learn new things quickly.
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Required Skills
Soft Skills
●Be an excellent communicator
–Written
–Verbal
–Communicating
technical information clearly and
concisely is extremely hard!
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Adaptability
–The
landscape is constantly changing. Stay ahead of
the curve by keeping track of current development,
maintaining current training, and trying new things.
Required Skills
Soft Skills
●Tolerance, Patience and Compassion
–End
–Put
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users can be difficult and unreasonable
yourself in their shoes
Self-Motivating
–Often,
the only time you hear from users is when there’s
something wrong. The best ones remember to praise you
when things go right, but don’t rely on it for motivation
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Creativity
–Ability
to think outside the box and come up with
creative solutions to problems
Successful System Admins
Generalize.
–They become a Jack-of-all-Trades. They don’t get
trapped in a specific technology or product.
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Are expert problem solvers.
–They understand how to attack the unknown in
manageable, measured steps.
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Are very good at time management.
–They manage information and workflow effectively.
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Successful System Admins
Think ahead.
–Put monitoring systems in place before the problem
exists. Identify bottlenecks and weaknesses and
address them.
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Solve a problem once.
–Build a permanent solution, not a one-time hack job.
“Higher Order Administration”
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Are often outgoing, social people