| Installation Guide9.16. Write changes to diskThe installer prompts you to confirm the partitioning options that you selected. Click Write changes to disk to allow the installer to partition your hard drive and install Red Hat Enterprise Linux. If you are certain that you want to proceed, click Write changes to disk. Up to this point in the installation process, the installer has made no lasting changes to your computer. When you click Write changes to disk, the installer will allocate space on your hard drive and start to transfer Red Hat Enterprise Linux into this space. Depending on the partitioning option that you chose, this process might include erasing data that already exists on your computer. To revise any of the choices that you made up to this point, click Go back. To cancel installation completely, switch off your computer. To switch off most computers at this stage, press the power button and hold it down for a few seconds. After you click Write changes to disk, allow the installation process to complete. If the process is interrupted (for example, by you switching off or resetting the computer, or by a power outage) you will probably not be able to use your computer until you restart and complete the Red Hat Enterprise Linux installation process, or install a different operating system. 9.17. x86, AMD64, and Intel 64 Boot Loader ConfigurationTo boot the system without boot media, you usually need to install a boot loader. A boot loader is the first software program that runs when a computer starts. It is responsible for loading and transferring control to the operating system kernel software. The kernel, in turn, initializes the rest of the operating system. If you install Red Hat Enterprise Linux in text mode, the installer configures the bootloader automatically and you cannot customize bootloader settings during the installation process. GRUB (GRand Unified Bootloader), which is installed by default, is a very powerful boot loader. GRUB can load a variety of free operating systems, as well as proprietary operating systems with chain-loading (the mechanism for loading unsupported operating systems, such as Windows, by loading another boot loader). Note that the version of GRUB in Red Hat Enterprise Linux 6 is an old and stable version now known as "GRUB Legacy" since upstream development moved to GRUB 2. Red Hat remains committed to maintaining the version of GRUB that we ship with Red Hat Enterprise Linux 6, just as we do with all packages that we ship. The GRUB menu defaults to being hidden, except on dual-boot systems. To show the GRUB menu during system boot, press and hold the Shift key before the kernel is loaded. (Any other key works as well but the Shift key is the safest to use.) If there are no other operating systems on your computer, or you are completely removing any other operating systems the installation program will install GRUB as your boot loader without any intervention. In that case you may continue on to Section 9.18, "Package Group Selection". You may have a boot loader installed on your system already. An operating system may install its own preferred boot loader, or you may have installed a third-party boot loader.If your boot loader does not recognize Linux partitions, you may not be able to boot Red Hat Enterprise Linux. Use GRUB as your boot loader to boot Linux and most other operating systems. Follow the directions in this chapter to install GRUB. If you install GRUB, it may overwrite your existing boot loader. By default, the installation program installs GRUB in the master boot record or MBR, of the device for the root file system. To decline installation of a new boot loader, unselect Install boot loader on /dev/sda. If you choose not to install GRUB for any reason, you will not be able to boot the system directly, and you must use another boot method (such as a commercial boot loader application). Use this option only if you are sure you have another way of booting the system! If you have other operating systems already installed, Red Hat Enterprise Linux attempts to automatically detect and configure GRUB to boot them. You may manually configure any additional operating systems if GRUB does not detect them. To add, remove, or change the detected operating system settings, use the options provided. - Add
Select Add to include an additional operating system in GRUB. Select the disk partition which contains the bootable operating system from the drop-down list and give the entry a label. GRUB displays this label in its boot menu. - Edit
To change an entry in the GRUB boot menu, select the entry and then select Edit. - Delete
To remove an entry from the GRUB boot menu, select the entry and then select Delete.
Select Default beside the preferred boot partition to choose your default bootable OS. You cannot move forward in the installation unless you choose a default boot image. The Label column lists what you must enter at the boot prompt, in non-graphical boot loaders, in order to boot the desired operating system. Once you have loaded the GRUB boot screen, use the arrow keys to choose a boot label or type e for edit. You are presented with a list of items in the configuration file for the boot label you have selected. Boot loader passwords provide a security mechanism in an environment where physical access to your server is available. If you are installing a boot loader, you should create a password to protect your system. Without a boot loader password, users with access to your system can pass options to the kernel which can compromise your system security. With a boot loader password in place, the password must first be entered before selecting any non-standard boot options. However, it is still possible for someone with physical access to the machine to boot from a diskette, CD-ROM, DVD, or USB media if the BIOS supports it. Security plans which include boot loader passwords should also address alternate boot methods. You may not require a GRUB password if your system only has trusted operators, or is physically secured with controlled console access. However, if an untrusted person can get physical access to your computer's keyboard and monitor, that person can reboot the system and access GRUB. A password is helpful in this case. If you choose to use a boot loader password to enhance your system security, be sure to select the checkbox labeled Use a boot loader password. Once selected, enter a password and confirm it. GRUB stores the password in encrypted form, so it cannot be read or recovered. If you forget the boot password, boot the system normally and then change the password entry in the /boot/grub/grub.conf file. If you cannot boot, you may be able to use the "rescue" mode on the first Red Hat Enterprise Linux installation disc to reset the GRUB password. If you do need to change the GRUB password, use the grub-md5-crypt utility. For information on using this utility, use the command man grub-md5-crypt in a terminal window to read the manual pages. When selecting a GRUB password, be aware that GRUB recognizes only the QWERTY keyboard layout, regardless of the keyboard actually attached to the system. If you use a keyboard with a significantly different layout, it might be more effective to memorize a pattern of keystrokes rather than the word that the pattern produces. To configure more advanced boot loader options, such as changing the drive order or passing options to the kernel, be sure Configure advanced boot loader options is selected before clicking Next. 9.17.1. Advanced Boot Loader ConfigurationNow that you have chosen which boot loader to install, you can also determine where you want the boot loader to be installed. You may install the boot loader in one of two places: The master boot record (MBR) - This is the recommended place to install a boot loader, unless the MBR already starts another operating system loader, such as System Commander. The MBR is a special area on your hard drive that is automatically loaded by your computer's BIOS, and is the earliest point at which the boot loader can take control of the boot process. If you install it in the MBR, when your machine boots, GRUB presents a boot prompt. You can then boot Red Hat Enterprise Linux or any other operating system that you have configured the boot loader to boot. The first sector of your boot partition - This is recommended if you are already using another boot loader on your system. In this case, your other boot loader takes control first. You can then configure that boot loader to start GRUB, which then boots Red Hat Enterprise Linux. If you install GRUB as a secondary boot loader, you must reconfigure your primary boot loader whenever you install and boot from a new kernel. The kernel of an operating system such as Microsoft Windows does not boot in the same fashion. Most users therefore use GRUB as the primary boot loader on dual-boot systems.
If you have a RAID card, be aware that some BIOSes do not support booting from the RAID card. In cases such as these, the boot loader should not be installed on the MBR of the RAID array. Rather, the boot loader should be installed on the MBR of the same drive as the /boot/ partition was created. If your system only uses Red Hat Enterprise Linux, you should choose the MBR. Click the Change Drive Order button if you would like to rearrange the drive order or if your BIOS does not return the correct drive order. Changing the drive order may be useful if you have multiple SCSI adapters, or both SCSI and IDE adapters, and you want to boot from the SCSI device. While partitioning your hard drive, keep in mind that the BIOS in some older systems cannot access more than the first 1024 cylinders on a hard drive. If this is the case, leave enough room for the /boot Linux partition on the first 1024 cylinders of your hard drive to boot Linux. The other Linux partitions can be after cylinder 1024. In parted, 1024 cylinders equals 528MB. For more information, refer to: http://www.pcguide.com/ref/hdd/bios/sizeMB504-c.html Rescue mode provides the ability to boot a small Red Hat Enterprise Linux environment entirely from boot media or some other boot method instead of the system's hard drive. There may be times when you are unable to get Red Hat Enterprise Linux running completely enough to access files on your system's hard drive. Using rescue mode, you can access the files stored on your system's hard drive, even if you cannot actually run Red Hat Enterprise Linux from that hard drive. If you need to use rescue mode, try the following method: Boot an x86, AMD64, or Intel 64 system from any installation medium, such as CD, DVD, USB, or PXE, and type linux rescue at the installation boot prompt. Refer to Chapter 36, Basic System Recovery for a more complete description of rescue mode.
For additional information, refer to the Red Hat Enterprise Linux Deployment Guide. 9.17.3. Alternative Boot LoadersGRUB is the default bootloader for Red Hat Enterprise Linux, but is not the only choice. A variety of open-source and proprietary alternatives to GRUB are available to load Red Hat Enterprise Linux, including LILO, SYSLINUX, and Acronis Disk Director Suite. Red Hat does not provide customer support for third-party boot loaders. 9.18. Package Group SelectionNow that you have made most of the choices for your installation, you are ready to confirm the default package selection or customize packages for your system. The Package Installation Defaults screen appears and details the default package set for your Red Hat Enterprise Linux installation. This screen varies depending on the version of Red Hat Enterprise Linux you are installing. If you install Red Hat Enterprise Linux in text mode, you cannot make package selections. The installer automatically selects packages only from the base and core groups. These packages are sufficient to ensure that the system is operational at the end of the installation process, ready to install updates and new packages. To change the package selection, complete the installation, then use the Add/Remove Software application to make desired changes. By default, the Red Hat Enterprise Linux installation process loads a selection of software that is suitable for a system deployed as a basic server. Note that this installation does not include a graphical environment. To include a selection of software suitable for other roles, click the radio button that corresponds to one of the following options: - Basic Server
This option provides a basic installation of Red Hat Enterprise Linux for use on a server. - Database Server
This option provides the MySQL and PostgreSQL databases. - Web server
This option provides the Apache web server. - Enterprise Identity Server Base
This option provides OpenLDAP and Enterprise Identity Management (IPA) to create an identity and authentication server. - Virtual Host
This option provides the KVM and Virtual Machine Manager tools to create a host for virtual machines. - Desktop
This option provides the OpenOffice.org productivity suite, graphical tools such as the GIMP, and multimedia applications. - Software Development Workstation
This option provides the necessary tools to compile software on your Red Hat Enterprise Linux system. - Minimal
This option provides only the packages essential to run Red Hat Enterprise Linux. A minimal installation provides the basis for a single-purpose server or desktop appliance and maximizes performance and security on such an installation.
To customize your package set further, select the Customize now option on the screen. Clicking Next takes you to the Package Group Selection screen. 9.18.1. Installing from Additional RepositoriesYou can define additional repositories to increase the software available to your system during installation. A repository is a network location that stores software packages along with metadata that describes them. Many of the software packages used in Red Hat Enterprise Linux require other software to be installed. The installer uses the metadata to ensure that these requirements are met for every piece of software you select for installation. The basic options are: The High Availability repository includes packages for high-availability clustering (also known as failover clustering) using the Red Hat High-availability Service Management component. The Load Balancer repository includes packages for load-balancing clustering using Linux Virtual Server (LVS). The Red Hat Enterprise Linux repository is automatically selected for you. It contains the complete collection of software that was released as Red Hat Enterprise Linux 6, with the various pieces of software in their versions that were current at the time of release. The Resilient Storage repository includes packages for storage clustering using the Red Hat global file system (GFS).
To include software from extra repositories, select Add additional software repositories and provide the location of the repository. To edit an existing software repository location, select the repository in the list and then select Modify repository. If you change the repository information during a non-network installation, such as from a Red Hat Enterprise Linux DVD, the installer prompts you for network configuration information. Select an interface from the drop-down menu. Click OK.
Anaconda activates the interface that you selected, then starts NetworkManager to allow you to configure the interface. If you select Add additional software repositories, the Edit repository dialog appears. Provide a Repository name and the Repository URL for its location. Once you have located a mirror, to determine the URL to use, find the directory on the mirror that contains a directory named repodata. Once you provide information for an additional repository, the installer reads the package metadata over the network. Software that is specially marked is then included in the package group selection system. If you choose Back from the package selection screen, any extra repository data you may have entered is lost. This allows you to effectively cancel extra repositories. Currently there is no way to cancel only a single repository once entered. 9.18.2. Customizing the Software Selection Your Red Hat Enterprise Linux system automatically supports the language that you selected at the start of the installation process. To include support for additional languages, select the package group for those languages from the Languages category. Select Customize now to specify the software packages for your final system in more detail. This option causes the installation process to display an additional customization screen when you select Next. Red Hat Enterprise Linux divides the included software into package groups. For ease of use, the package selection screen displays these groups as categories. You can select package groups, which group components together according to function (for example, X Window System and Editors), individual packages, or a combination of the two. To view the package groups for a category, select the category from the list on the left. The list on the right displays the package groups for the currently selected category. To specify a package group for installation, select the check box next to the group. The box at the bottom of the screen displays the details of the package group that is currently highlighted. None of the packages from a group will be installed unless the check box for that group is selected. If you select a package group, Red Hat Enterprise Linux automatically installs the base and mandatory packages for that group. To change which optional packages within a selected group will be installed, select the Optional Packages button under the description of the group. Then use the check box next to an individual package name to change its selection. In the package selection list on the right, you can use the context menu as a shortcut to select or de-select base and mandatory packages or all optional packages. After you choose the desired packages, select Next to proceed. The installer checks your selection, and automatically adds any extra packages required to use the software you selected. When you have finished selecting packages, click Close to save your optional package selections and return to the main package selection screen. The packages that you select are not permanent. After you boot your system, use the Add/Remove Software tool to either install new software or remove installed packages. To run this tool, from the main menu, select ⤍ ⤍ . The Red Hat Enterprise Linux software management system downloads the latest packages from network servers, rather than using those on the installation discs. 9.18.2.1. Core Network Services All Red Hat Enterprise Linux installations include the following network services: centralized logging through syslog email through SMTP (Simple Mail Transfer Protocol) network file sharing through NFS (Network File System) remote access through SSH (Secure SHell) resource advertising through mDNS (multicast DNS)
The default installation also provides: network file transfer through HTTP (HyperText Transfer Protocol) printing through CUPS (Common UNIX Printing System) remote desktop access through VNC (Virtual Network Computing)
Some automated processes on your Red Hat Enterprise Linux system use the email service to send reports and messages to the system administrator. By default, the email, logging, and printing services do not accept connections from other systems. Red Hat Enterprise Linux installs the NFS sharing, HTTP, and VNC components without enabling those services. You may configure your Red Hat Enterprise Linux system after installation to offer email, file sharing, logging, printing and remote desktop access services. The SSH service is enabled by default. You may use NFS to access files on other systems without enabling the NFS sharing service. 9.19. Installing PackagesAt this point there is nothing left for you to do until all the packages have been installed. How quickly this happens depends on the number of packages you have selected and your computer's speed. Depending on the available resources, you might see the following progress bar while the installer resolves dependencies of the packages you selected for installation: Red Hat Enterprise Linux reports the installation progress on the screen as it writes the selected packages to your system. For your reference, a complete log of your installation can be found in /root/install.log once you reboot your system. After installation completes, select Reboot to restart your computer. Red Hat Enterprise Linux ejects any loaded discs before the computer reboots. 9.20. Installation CompleteCongratulations! Your Red Hat Enterprise Linux installation is now complete! The installation program prompts you to prepare your system for reboot. Remember to remove any installation media if it is not ejected automatically upon reboot. After your computer's normal power-up sequence has completed, Red Hat Enterprise Linux loads and starts. By default, the start process is hidden behind a graphical screen that displays a progress bar. Eventually, a login: prompt or a GUI login screen (if you installed the X Window System and chose to start X automatically) appears. The first time you start your Red Hat Enterprise Linux system in run level 5 (the graphical run level), the FirstBoot tool appears, which guides you through the Red Hat Enterprise Linux configuration. Using this tool, you can set your system time and date, install software, register your machine with Red Hat Network, and more. FirstBoot lets you configure your environment at the beginning, so that you can get started using your Red Hat Enterprise Linux system quickly. Chapter 10. Troubleshooting Installation on an Intel or AMD SystemThis section discusses some common installation problems and their solutions. For debugging purposes, anaconda logs installation actions into files in the /tmp directory. These files include: /tmp/anaconda.loggeneral anaconda messages /tmp/program.logall external programs run by anaconda /tmp/storage.logextensive storage module information /tmp/yum.logyum package installation messages /tmp/sysloghardware-related system messages
If the installation fails, the messages from these files are consolidated into /tmp/anaconda-tb-identifier, where identifier is a random string. All of the files above reside in the installer's ramdisk and are thus volatile. To make a permanent copy, copy those files to another system on the network using scp on the installation image (not the other way round). |
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