Introducción a la Administración de Sistemas Informáticos. Francisco Rosales frosal@fi.upm.es

Transcripción

1 Introducción a la Administración de Sistemas Informáticos Francisco Rosales frosal@fi.upm.es 1

2 Índice de contenidos Definiciones La figura del Administrador Tipos de Instalaciones Herramientas Sistemas Operativos Conocimientos SAGE Job Description Certificaciones Principios y Buenas Prácticas Bibliografía 2

3 Administración - definición Administrar 1. Dirigir, gobernar, ejercer la autoridad o el mando. 2. Ordenar, disponer, organizar. 3. Suministrar, proporcionar o distribuir. 4. Graduar o dosificar el uso de algo, para obtener mayor rendimiento de ello o para que produzca mejor efecto. 3

4 Sistemas - definición Sistema 1. Conjunto de cosas que relacionadas entre sí ordenadamente contribuyen a determinado objeto. ~ operativo 1. Programa o conjunto de programas que efectúan la gestión de los procesos básicos de un sistema informático, y permite la normal ejecución del resto de las operaciones. 4

5 Informáticos - definición Informática 1. Conjunto de conocimientos científicos y técnicas que hacen posible el tratamiento automático de la información por medio de ordenadores. 5

6 Sistema informático - definición Sistema informático Conjunto interrelacionado de hardware, software y recurso humano que permite almacenar y procesar información. El hardware incluye las computadoras y sus dispositivos. El software incluye el sistema operativo, el firmware y las aplicaciones. El soporte humano incluye al personal técnico (analistas, programadores, operarios, etc.) y a los usuarios.... 6

7 La figura del Administrador Quién es el administrador? Persona encargada de configurar y administrar el sistema Ideal: una persona encargada sólo de la administración En ocasiones: compagina su trabajo y el de administración Qué se espera del administrador? Amplios conocimientos de todo el sistema: hardware, software, datos, usuarios,... Capacidad reconocida para tomar decisiones Ambición y espíritu de superación Eficacia y moral irreprochables Responsabilidad: se trabaja con datos muy importantes, hay un jefe por encima,... El administrador tiene que tener por un lado autoridad y responsabilidad, por otro servicio y cooperación (BY:) Mª Pilar González ditec.um.es 7

8 Como actúa el Administrador Estrategias del administrador al realizar una tarea: Planearlo antes de hacer los cambios, haciendo un estudio detallado de los pasos que hay que realizar Hacer los cambios reversibles, haciendo copia de seguridad del sistema o de los ficheros de configuración a modificar Realizar los cambios incrementalmente, probándolos si fuese posible. (De esta manera se localizarán los fallos más fácilmente) Probarlo, probarlo, probarlo,..., antes de hacerlo público Conocer cómo realmente trabajan las cosas Al realizar una modificación: Precaución antes de... Testear después de... Es recomendable tener un cuaderno de bitácora para registrar todos los cambios (p.e. /etc/informacion) (BY:) Mª Pilar González ditec.um.es 8

9 Tareas esenciales del Administrador Añadir nuevos usuarios Controlar el rendimiento del sistema Realizar las copias de seguridad (y restaurarlas...) Añadir/eliminar elementos hardware Instalar/actualizar software (o desinstalar... ) Controlar la seguridad del sistema Controlar el correcto arranque del sistema Monitorización del sistema «Localizar» y resolver problemas del sistema Resolver dudas de los usuarios......todo lo cual puede precisar desarrollo software y scripting (BY:) Mª Pilar González ditec.um.es 9

10 Superusuario o Administrador Para administrar, existe un usuario privilegiado, que puede realizar cualquier acción sobre el sistema saltándose toda protección En Windows es el Administrador y pertenece al grupo Administrador En Unix es el superusuario o root y pertenece al grupo root HOME: /root (en modo singleuser es /) Alternativas para administrar: Entrar al sistema como usuario root Ejecutar orden su que crea una shell de superusuario Ejecutar la orden sudo, que puntualmente ejecuta algo como superusuario $ whoami $ id mengano uid=1001(mengano) gid=1000(users) $ su $ sudo id Password: **** password for mengano: **** # whoami uid=0(root) gid=0(root) root $ (BY:) Mª Pilar González ditec.um.es 10

11 Tipos de instalaciones Estaciones de trabajo monousuario: Administración sencilla (uno o muy pocos usuarios) Administrador == usuario Instalaciones poco críticas Servidores multiusuario: Mayor número de usuarios Arbitraje de recursos (limitaciones y privilegios) Modificaciones más delicadas Clusters de máquinas: Red: problemas de seguridad y mayor complejidad Para gran cantidad de máquinas: automatización de tareas La complejidad crece sustancialmente 11

12 Herramientas de Administración Casi todos los sistemas operativos UNIX tienen su propio conjunto de herramientas de administración: admintool (Sun Solaris) control-panel (Linux-RedHat) Yast (Linux-SuSe) smit (IBM AIX) sysadmsh (XENIX) La administración de sistemas del día a día se hace por medio de estas herramientas Otras operaciones precisan herramientas específicas o programación/scripting ad-hoc 12

13 Conocimientos del Administrador Funcionamiento interno del sistema: Diseño interno del sistema operativo Permite comprender qué hace cada operación, causas y motivos del funcionamiento del sistema Seguridad y comunicaciones: En la actualidad los equipos están en red Los servicios de red de una máquina son cruciales Programación (scripts, perl, awk,...): Automatización de tareas: Si lo necesitas una vez lo vas a hacer varias Instalación de componentes hardware: Discos duros, periféricos,... Otros sistemas operativos, servicios de conectividad 13

14 Sistemas Operativos 14

15 Evolución de Unix 15

16 Evolución de Windows 16

17 LISA (antes SAGE) USENIX special interest group for system administrators: To enhance technical and managerial capabilities of the profession To promote activities that advance the state of the art or the community To providing tools, information, and services to assist system administrators To establish standards of professional excellence (BY:) Robert csciwww.etsu.edu 17

18 SAGE Site levels SAGE Site size Small uniform Complex Large complex Number of computers: <50 computers up to 100 systems >100 computers Operating systems: all running the same running more than 2 potentially running more operating system operating systems than one operating system Number of users: 20 or fewer users up to 100 users >100 or more users (A computer used only by the administrator does not qualify as a site)

19 SAGE Level vs. Skills vs. Level I - Novice Level II - Junior Level III - Intermediate Level IV - Senior Skills: Can explain simple procedures in writing or verbally, has good phone skills Familiar with OS commands/utilities at a user level - can edit files, use a shell, find users' home directories, navigate through the file system, use i/o redirection, etc. Can train users in applications and OS fundamentals, and writing basic documentation High skill with OS commands/utilities - can boot/shutdown a machine, can add/remove user accounts; also understands soft and hard links, distinctions between the kernel and the shell, etc. Can write purchase justifications, train users in complex topics, make internal presentations, and interact positively with upper management. Independent problem solving; selfdirection Is comfortable with most aspects of OS can configure mail, install/ configure systems, setup printing, manage basic security, install software, use nslookup/dig; also understands paging and swapping, process communication, devices and drivers, file systems, basics of routing, etc. Can write proposals or papers, acts as vendor liaison, makes presentations to customers/clients/peers, and works closely with upper management Understands all aspects of OS system tuning, client/server programming, design of consistent network-wide file system layouts, etc. Is able to follow instructions well Can write scripts in some administrative language (Perl, VBScript, shell, etc.) Ability to write scripts in some administrative language and do minimal debugging and modification of C programs Ability to program in an administrative language, to port C programs from one platform to another, and to write small C programs Ability to solve problems quickly, often by use of automation

20 SAGE Level vs. Background and Others vs. Level I - Novice Level II - Junior Level III - Intermediate Level IV - Senior Background: Two years of college or equivalent education or experience A degree or certificate in computer science or a related field One to three years of system administration experience A degree in computer science or a related field Three to five years systems administration experience A degree in computer science or a related field More than five years previous systems administration experience A degree and publications in computer science or a related field Other desirables: Previous experience in customer support, computer operations, system administration or another related area; Motivated to advance in the profession Programming experience in any applicable language Familiarity with networked/distributed computing environment concepts; for example, can use the route command, add a workstation to a network, and mount remote file systems Significant programming background in any applicable language Extensive programming background in any applicable language

21 SAGE Level vs. Responsabilities vs. Level I - Novice Level II - Junior Level III - Intermediate Level IV - Senior Appropriate responsibilities: Performs routine tasks under direct supervision Acts as a front-line interface to users, accepting trouble reports and dispatching them to appropriate system administrators Administers a small site alone or assists in the administration of a larger system; Works under general supervision Administers a mid-sized site alone or assists in administration of a large site and manages novice system administrators or operators Initiates some new responsibilities and helps plan for the future Evaluates/recommends purchases; has strong influence on purchasing Works under senior management to design/implement complex networks of machines or manage a large site or network Establishes/recommends policies on system use and services Has purchasing authority and responsibility for purchase justification Supervises system administrators, system programmers, or others of equivalent seniority

22 SAGE Other skills to consider Networking Skills Experience configuring file systems, synchronization, automounters, license managers, NIS/NIS+, TCP/IP, high-speed networking, routers, modem pools/terminal servers, etc. Security Experience building firewalls, deploying authentication systems, or applying cryptography; Experience with passwords, uids/gids, permissions, file system integrity, security packages Site Specialities Experience at sites with over 1000 computers, users, or disk space; Experience coordinating multiple independent computer facilities (for example, working for the central group at a large company or university); Experience with high uptime requirements, disaster recovery, etc. Heterogeneity Experience Experience working in an environment with more than one operating system Documentation Background in technical publications, documentation, or desktop publishing Databases Experience using relational databases, a database query language, or as a DBA Hardware Experience installing and maintaining network cabling, boards and memory, SCSI devices, peripherals, etc; Experience with board or component level diagnosis and Management Budget responsibility; Experience in writing personnel reviews, and ranking processes; Experience in interviewing/hiring Local Environment Experience Experience with the specific OS, applications, languages or with the work done by the users

23 Microsoft Certifications MCSE 7 Exams (4 networking, 1 client, 1 design, 1 elective) MCSA 4 Exams (2 networking, 1 client, 1 elective) (BY:) Robert csciwww.etsu.edu 23

24 Red Hat Certifications Red Hat Certified Technician (RHCT) Entry-level certification focuses on single-system administration Red Hat Certified Engineer (RHCE) Expands the RHCT with a focus on services and security Red Hat Certified Architect (RHCA) Five additional endorsements to RHCE, adds enterprise-level focus, from clustering to deploying systems Red Hat Certified Security Specialist (RHCSS) Includes two exams more than RHCA plus an SELinux exam 24

25 Other Certification/Training Linux Professional Institute (LPI) CompTIA Novell O'Reilly School of Technology 25

26 Mark Burgess' Principles of System Administration 1- Policy is the foundation 2- Predictability (is the goal) 3- Scalability (is often important) 4- Minimum privilege (restriction of unnecessary privilege protects a system from accidental and malicious damage) 4- Corollary: don't work as Administrator/root 5- Communities (each member needs to consider ramifications of actions) 6- Uniformity (increases predictability may decrease costs) (BY:) Robert csciwww.etsu.edu 26

27 Mark Burgess' Principles of System Administration (cont) 7- Variety (is a method of risk management and higher flexibility, may increase costs) 8- Delegation, aka 'Specialization' (specialization allows experts to develop, who can then do tasks more efficiently and more cost effectively) 9- Resource map: A resource map of a site aids the predictability of the system by allowing an administrator to learn about the parts of the system, understand inter-relationships and prepare a contingency plan for expected problems with the specific elements 9b- Resource map: removes ambiguity and increases knowledge of the environment for administrators, users, and managers 27

28 Mark Burgess' Principles of System Administration (cont) Good ideas for students: * learn to learn independently * systematic and organized work habits * balance between reality (problems happen) vs. Utopia Bad ideas for students: * expect a single right answer to every problem * get stuck due to frustration * expect the textbook/manual/instructor/guru to be able to accurately and completely answer every question 28

29 Guías de buenas prácticas Recomendaciones ITIL (Information Technology Infrastructure Library): Guía de buenas prácticas en servicios TIC. Incluye gestión de incidencias, atención a usuarios, mantenimiento y cambios. COBIT (Control Objectives for Information and related Technology): Certificación otorgada por ISACA/ITGI. Dividida en objetivos y dominios. ISO/IEC (Gestión de servicios TIC) 29

30 Unix Unix System Administration Handbook. Evi Nemeth, Garth Snyder,. Prentice Hall 4th Edition 2006 Essential System Administration - Help for UNIX System Administration. Æleen Frisch. O'Reilly - 2nd Edition 1995 The Practice of System and Network Administration. Thomas A. Limoncelli, Christine Hogan. Addison Wesley 2001 Linux Bibliografía Linux System Administrator s Guide ( Security & Optimizing Linux ( Linux Network Administrator s Guide ( 30

31 Bibliografía Windows Windows Server 2008: The Definitive Guide. Jonathan Hassell. O'Reilly 2008 Active Directory: Designing, Deploying, and Running Active Directory. Brian Desmond, Joe Richards, Robbie Allen, Alistair G. Loewe-Norris. O'Reilly 4th Edition 2008 Windows Administration Resource Kit: Productivity Solutions for IT Professionals. Dan Holme. Microsoft Press

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