COSC 4750

CentOS Installation and maintenance

Installation

• Pretty easy to do

• Requires a minimum amount of knowledge on the part of the installer

• Finds most hardware during the installation– May have problems with some laptops and very

new motherboards (mostly video issues).

• Can be installed using a boot disk and the CDROM

• Just the CDROM, if you can boot from the CDROM

• A boot disk (CD, USB or specialized floppies) and install from the network, if you have a network card

• The installation can be done in several modes– Normal: Uses a GUI interface to ask questions– text: No GUI interface, used when it is unable

to detect your monitor/video card correctly– expert: Expected you know what you are doing.– Askmethod: uses normal and asks if you want

to use network.

With CDs

• It will tell you a CD was found.

• Then asks if you want to verify the media.– Make sure all 4 disks are good and it can install

from them.

– Takes 30 to 60 minutes depending on the CDROM drive.

Normal mode

• The installer will begin up a GUI interface now, if you using local media

1. Which language– English is default

2. Keyboard Configuration: – us

3. Mouse type:- Default is normally correct. (wheeled Mouse PS/2)

If network install

• Wants to know if it should use DHCP or static IP number– May need a network driver disk.

• Then where to get the files from

• Once it finds the install media, it will startup the GUI interface.

Upgrade options

• If a version of linux is installed, it will ask– Upgrade

• Lists current version.

– New install

Install Type

• Personal desktop install– Meant for personal computers and laptops– Installs GUI– No server deamons installed.

• i.e. can’t telnet into this machine, because there is no telnet server.

– Min install 2.3GB

• If running Windows, will automatically configure for dual-boot

Install Type (2)

• Workstation and laptop class– Install everything from Personal desktop– Installs development environment – Installs system admin tools.

– Requires at least 3 GB free disk space

Install Type (3)

• Server-Class– Must choose to install X Windows system – Install network applications, such as file and

printer sharing, web services, – Removes ALL existing partitions on ALL

drives– Need at least 1.1GB of disk space, without X-

windows

Install Type (4)

• Custom Install– 620 MB minimum install, max 9 GB

– You select packages to be installed

– Configure grub if necessary

• Upgrading system– Will not delete any data (backup anyway)

– upgrades the kernel and all installed packages, if able to.

• May require of max of 9 GB to upgrade the system.

Custom Installation

• Partition drives– Have installer auto partition

• Choose to erase only linux partitions, all partitions, or only use free space• Will setup swap partition, /boot partition which is 100 megs, and the rest goes

to the / partition– Note: swap for partition 2x until 2GB, then 1x after that. Min of 64MB.

• Allows you to review and make changes.– Using Disk Druid (linux Druid = Windows Wizard)

• Easier to use then fdisk• Fewer mistakes can be made with Disk Druid

– Need at least a / and swap partition in order to install the system– Recommended for servers, you have /, /boot, /usr, /home, /tmp, /var, and

swap. /usr needs to be at least 5 GB (for a full installation).– For workstations or personal machines, the auto partition works very well.– Using fdisk

• Complicated, similar to Microsoft fdisk program.

• With Disk druid, you request how much space you want to partition and it assigns it as close a possible

• typically: 500MB comes out as 502MB– Due to drive restriction, sectors, and partitions

already created.

• Has “Grow to fill disk” option. Use it on the last partition to get the rest of the space.

Partitions to Format

• The installer will ask which partitions to format. You don’t have format all of them, unless they are new.

• checking for bad blocks while formatting– Normally a good idea, but it takes about an

hour to check a 4GB to 8GB drive– We’ll be using 20+ GB drives in lab.

Boot loader configuration

• If you plan to boot only from a floppy disk, you can skip the configuration– It created near the end of the installation. Also useful

when lilo/grub has failed or other problems booting.

• Otherwise choose lilo or grub as the boot loader• If will list dual boot options automatic for you

– If it is able to find them correctly.– Choose when one you want to boot by default

• You can then opt for a boot password

• For SMP (symmetric Multi Processor) motherboards, grub will create two boot entries. – 1. uses all the processors

• Normal use

– 2. uses only one processor• for use when you are having problems with a

processor

Network Configuration

• Choose DHCP or manual– DHCP will ask the DHCP server for all the

network information that it needs.

• Choose Activate on boot– Will your networking start when the system

boots

Manual Network Settings

• Need IP number, Netmask, Network, and Broadcast– Example: IP 129.72.216.101, Netmask: 255.255.255.0,

Network: 129.72.216.0, and Broadcast 129.72.216.255

• Also Need Hostname, Gateway, Primary DNS, 2nd (if known), and 3rd (if known), DNS search– Hostname:rhinst, Gateway: 129.72.216.1, DNS:

129.72.216.4, 129.72.216.13, 129.72.60.8, Search cs.uwyo.edu, uwyo.edu

Firewall Configuration

• Security level: High– Only DHCP can connect to the computer– NOT allowed: FTP, IRC DCC file transfers,

RealAudio, Remote X windows clients– Good for computers connected to the internet,

but not servers

• Security level: medium– Allows all Ports lower than 1023 to accessed

• FTP, SSH, telnet, HTTP, etc.

– NFS server port allowed, Remote X clients, and X Font server (xfs is disable by default)

– RealAudio does work.

• Security level: No firewall– No blocking.

Language Support

• By default it installs English

• You can choose to add more languages– Or remove english and install another one.

Time Zone Configuration

• You can choose you location or UTC (Universal Coordinated Time)

• Location is Denver, Mountain Standard time.• UTC for Wyoming is UTC-07 US Mountain

– You can also choose to use Daylight Savings Time as well.

• Setting the system clock to UTC– The time on files will be UTC instead of local time.

• UTC is GMT

Set root password.

• Account Creation– Set the root password– Can also create other user accounts at this time.

• Authentication Configuration– MD5 Password: Can use up to 256 characters,

instead of the normal 8 or less– Shadow Password: Passwords are stored in a

file called: /etc/shadow

Package Group Selection

• You select components to install– Can choose everything (need max of 7 GB of

disk space)– Choose Minimal need only 620 MB

• You can also choose to select individual packages, instead of component group– choose only www, instead of Mail/WWW/news

tools.

Package installation

• At this point the installer, formats the hard drives, and installs the packages selected and configures the system.

• Testing in our lab with a network install,– The actually package installation took about 45

minutes to install everything.

Finish the install.

• It will install all the packages and then ask you to reboot.

• Next it will bring up the “First Time boot” configurations

• Asks to agree to License agreement

Date and Time

• Enter correct time/date

• Setup Network Time Protocol to set the time automatically from a known time server.

• On campus, we use time.uwyo.edu instead of the ones listed.

Configure X

• Choose the resolution and color depth.

• You can also

• Choose a Monitor– Usually, Redhat normally chooses the correct

monitor by default, but always a good thing to check

• Choose a Video card, video memory– usually chooses the correct information by default

• May not select very new video cards correctly. Cards that are less then 6 months old.

– May have to deal with after the installation is completed.

• Also may have problems with laptop video cards.

• Many vendors offer video drivers, so you can check with their web site as well.

Account creation

• Account Creation– Can create user accounts at this time.

• Authentication Configuration– MD5 Password: Can use up to 256 characters,

instead of the normal 8 or less– Shadow Password: Passwords are stored in a

file called: /etc/shadow

User Authentication

– Enable NIS• Can use an existing group of computer accounts on

the network, instead of having to create account local to this machine.

– Enable LDAP, Hesiod, Kerberos5– Enable SMB

• Use a windows server to authenticate users. You still have to create local account, but use windows for passwords.

Done

• It should now boot in GUI multiuser mode.

• See if everything works.– Now it is time to customize your machine

• Next Time– Customizing– upgrading– maintenance