Chapter 36. Customizing boot parameters

Before the installation can begin, you must configure some mandatory boot parameters. When installing through z/VM, these parameters must be configured before you boot into the generic.prm file. When installing on an LPAR, the rd.cmdline parameter is set to ask by default, meaning that you will be given a prompt on which you can enter these boot parameters. In both cases, the required parameters are the same.


All network configuration must now be specified by either by using a parameter file, or at the prompt.

Installation source
An installation source must always be configured. Use the inst.repo option to specify the package source for the installation.
Network devices

Network configuration must be provided if network access will be required during the installation. If you plan to perform an unattended (Kickstart-based) installation by using only local media such as a disk, network configuration can be omitted.

Use the ip= option for basic network configuration, and other options as required.

Also use the rd.znet= kernel option, which takes a network protocol type, a comma delimited list of sub-channels, and, optionally, comma delimited sysfs parameter and value pairs. This parameter can be specified multiple times to activate multiple network devices.

For example:


When specifying multiple rd.znet boot options, only the last one is passed on to the kernel command line of the installed system. This does not affect the networking of the system since all network devices configured during installation are properly activated and configured at boot.

The qeth device driver assigns the same interface name for Ethernet and Hipersockets devices: enc<device number>. The bus ID is composed of the channel subsystem ID, subchannel set ID, and device number, separated by dots; the device number is the last part of the bus ID, without leading zeroes and dots. For example, the interface name will be enca00 for a device with the bus ID 0.0.0a00.

Storage devices

At least one storage device must always be configured for text mode installations.

The rd.dasd= option takes a Direct Access Storage Device (DASD) adapter device bus identifier. For multiple DASDs, specify the parameter multiple times, or use a comma separated list of bus IDs. To specify a range of DASDs, specify the first and the last bus ID.

For example:

rd.dasd=0.0.0200 rd.dasd=0.0.0202(ro),0.0.0203(ro:failfast),0.0.0205-0.0.0207

The rd.zfcp= option takes a SCSI over FCP (zFCP) adapter device bus identifier, a world wide port name (WWPN), and a FCP LUN, then activates the device. This parameter can be specified multiple times to activate multiple zFCP devices.

For example: Since 8, a target world wide port name (WWPN) and an FCP LUN have to be provided only if the zFCP device is not configured in NPIV mode or when auto LUN scanning is disabled by the zfcp.allow_lun_scan=0 kernel module parameter. It provides access to all SCSI devices found in the storage area network attached to the FCP device with the specified bus ID. This parameter needs to be specified at least twice to activate multiple paths to the same disks.

Kickstart options
If you are using a Kickstart file to perform an automatic installation, you must always specify the location of the Kickstart file using the inst.ks= option. For an unattended, fully automatic Kickstart installation, the inst.cmdline option is also useful.

An example customized generic.prm file containing all mandatory parameters look similar to the following example:

Example 36.1. Customized generic.prm file

ro ramdisk_size=40000 cio_ignore=all,!condev
rd.dasd=0.0.0200 rd.dasd=0.0.0202

Some installation methods also require a file with a mapping of the location of installation data in the file system of the DVD or FTP server and the memory locations where the data is to be copied.

The file is typically named generic.ins, and contains file names for the initial RAM disk, kernel image, and parameter file (generic.prm) and a memory location for each file. An example generic.ins will look similar to the following example:

Example 36.2. Sample generic.ins file

images/kernel.img 0x00000000
images/initrd.img 0x02000000
images/genericdvd.prm 0x00010480
images/initrd.addrsize 0x00010408

A valid generic.ins file is provided by Red Hat along with all other files required to boot the installer. Modify this file only if you want to, for example, load a different kernel version than default.

Additional resources