Chapter 28. Boot Options

The Red Hat Enterprise Linux installation system includes a range of functions and options for administrators. To use boot options, enter linux option at the boot: prompt.
To access the boot: prompt on a system that displays a graphical boot screen, press the Esc key while the graphical boot screen is displayed.
If you specify more than one option, separate each of the options by a single space. For example:
linux option1 option2 option3


The Red Hat Enterprise Linux installation and rescue discs may either boot with rescue mode, or load the installation system. For more information on rescue discs and rescue mode, refer to Section 28.6.2, “Booting Your Computer with the Rescue Mode”.

28.1. Configuring the Installation System at the Boot Menu

You can use the boot menu to specify a number of settings for the installation system, including:
  • language
  • display resolution
  • interface type
  • Installation method
  • network settings

28.1.1. Specifying the Language

To set the language for both the installation process and the final system, specify the ISO code for that language with the lang option. Use the keymap option to configure the correct keyboard layout.
For example, the ISO codes el_GR and gr identify the Greek language and the Greek keyboard layout:
linux lang=el_GR keymap=gr

28.1.2. Configuring the Interface

To use a specific display resolution, enter resolution=setting as a boot option. For example, to set the display resolution to 1024×768, enter:
linux resolution=1024x768
To run the installation process in text mode, enter:
linux text
To enable support for a serial console, enter serial as an additional option.
Use display=ip:0 to allow remote display forwarding. In this command, ip should be replaced with the IP address of the system on which you want the display to appear.
On the system you want the display to appear on, you must execute the command xhost +remotehostname, where remotehostname is the name of the host from which you are running the original display. Using the command xhost +remotehostname limits access to the remote display terminal and does not allow access from anyone or any system not specifically authorized for remote access.

28.1.3. Updating anaconda

You can install Red Hat Enterprise Linux with a newer version of the anaconda installation program than the one supplied on your installation media.
The boot option
linux updates
presents you with a prompt that asks you for a disk image containing anaconda updates. You do not need to specify this option if you are performing a network installation and have already placed the updates image contents in rhupdates/ on the server.


The rhupdates directory should only contain anaconda updates. The installation may fail if you add other files (such as errata RPMs) or if you place too much content in the directory.
To load the anaconda updates from a network location instead, use:
linux updates=
followed by the URL for the location where the updates are stored.

28.1.4. Specifying the Installation Method

Use the askmethod option to display additional menus that enable you to specify the installation method and network settings. You may also configure the installation method and network settings at the boot: prompt itself.
To specify the installation method from the boot: prompt, use the repo option. Refer to Table 28.1, “Installation methods” for the supported installation methods.

Table 28.1. Installation methods

Installation method Option format
DVD drive repo=cdrom:device
Hard Drive repo=hd:device/path
HTTP Server repo=http://host/path
HTTPS Server repo=https://host/path
FTP Server repo=ftp://username:password@host/path
NFS Server repo=nfs:server:/path
ISO images on an NFS Server repo=nfsiso:server:/path

28.1.5. Specifying the Network Settings

Normally, anaconda prompts you to configure a network interface if one is needed during installation. However, you can provide network settings with options at the boot: prompt as follows:
The system's IP address.
The system's netmask.
The IP address of the network gateway.
The IP address of the DNS server.
The network device to use with these settings.
The name you wish to assign to the network device, followed by the device's MAC address.
Each of these settings is required even if you are only configuring a single interface.
The following settings are optional:
The virtual LAN ID number (802.1q tag) for the specified network device.
The delay after which the network will be considered active. If you use this option, the system will wait after bringing up network interfaces until either the gateway is successfully pinged, or until the amount of seconds specified in this parameter passes. This is useful for some NICs which may report that a link is available before it actually is, causing any operations which require network access (such as Kickstart file downloads) to fail. Maximum value of this parameter is 30 as defined by NetworkManager; specifying a value higher than 30 will cause the option to be ignored.
This example configures the network settings for an installation system that uses the IP address for interface eth0. The interface is named primary, and the system will wait for 5 seconds or until it can successfully ping the gateway before continuing:
linux ip= netmask= gateway= dns= ksdevice=eth0 ifname=primary:01:23:45:67:89:ab nicdelay=5
If you specify the network configuration and network device at the boot: prompt, these settings are used for the installation process and the Networking Devices and Configure TCP/IP dialogs do not appear. Configuring a Bonded Interface

To configure a bonded network interface, use the bond option. Name the bonded interface, specify which network connections will be bonded, and list any additional options in the following format:
linux bond=<bondname>:<bondslaves>:[:<options>]
For example:
linux bond=bond0:eth0,eth1:mode=active-backup,primary=eth1
Available optional parameters are listed in the Working with Kernel Modules chapter of the Red Hat Enterprise Linux Deployment Guide.