chreipl - Modify the re-IPL configuration

SUSE Linux Enterprise Server 15 SP5 LPAR mode z/VM guest KVM guest

Use the chreipl tool to modify the re-IPL configuration for Linux® on IBM® Z. You can configure a particular device as the reboot device.

chreipl syntax

Notes:

¹ You can specify the <device_bus_id>, <wwpn>, and <lun> in any order if you use the corresponding command options.
² The -b option can be used if the device node or directory maps to a SCSI disk or NVMe device.

Where:

<device_bus_id> or -d <device_bus_id> or --device <device_bus_id>

specifies the device bus-ID of a CCW re-IPL device or of the FCP device through with a SCSI re-IPL device is attached.

<wwpn> or -w <wwpn> or --wwpn <wwpn>

specifies the worldwide port name (WWPN) of a SCSI re-IPL device.

<lun> or -l <lun> or --lun <lun>

specifies the logical unit number (LUN) of a SCSI re-IPL device.

nvme

declares that the following parameters refer to an NVMe device.

-i <function_id> or --fid <function_id>

specifies the PCIe function ID of the NVMe device. The function ID is an 8-digit hexadecimal value. Specify the ID with a leading 0x. In the value itself you can omit leading zeroes.

-s <namespace_id> or --nsid <namespace_id>

specifies the name space ID of the NVMe device. Name space IDs are assigned by NVMe disk controllers to divide a physical NVMe device into multiple logical devices. The name space ID is an 8-digit hexadecimal value. Specify the ID with a leading 0x. In the value itself you can omit leading zeroes. The default is 0x00000001, which is equivalent to 0x1.

<node>

specifies a device node of a DASD, SCSI , NVMe, or logical device mapper re-IPL device.

<dir>

specifies a directory in the Linux file system on the re-IPL device.

-c <n> or --clear <n>

controls memory clearing during the re-IPL. Possible values of <n> are 1 and 0:

0: does not clear memory during the re-IPL. This is the default.
1: clears all memory during the re-IPL. For large memory sizes, memory clearing can considerably slow down the re-IPL process. Use this setting if you must clear memory, even at the expense of a prolonged re-IPL procedure.

You cannot control memory clearing for all environments and re-IPL devices. For unsupported devices and environments, this option causes the command to fail with an error message.

This setting can affect the online state of hotplug memory after the re-IPL, see Memory state and reboot

nss

declares that the following parameters refer to a z/VM® named saved system (NSS).

Note: You cannot load SUSE Linux Enterprise Server 12 or later from an NSS. The NSS could contain a Linux distribution with NSS support or another mainframe operating system, for example, CMS.

<name> or -n <name> or --name <name>

specifies the name of an NSS as defined on the z/VM system.

Note: You cannot load SUSE Linux Enterprise Server 15 SP5 from an NSS. The NSS could contain a Linux distribution with NSS support or another mainframe operating system, for example, CMS.

-L <parm> or --loadparm <parm>

For SUSE Linux Enterprise Server 15 SP5 with a DASD, SCSI, or virtio block device as boot device, you can specify parameters for GRUB 2 with the syntax g<grub_parameters>. Typically, <grub_parameters> is a specification that selects an item from the GRUB 2 boot menu. For details, see Specifying GRUB 2 parameters.

For DASD, you can also specify a leading 0, 1, or 2.

For virtio block devices on KVM hosts, use the same syntax as for DASD.

0 or 1: immediately starts GRUB 2 for booting the target SUSE Linux Enterprise Server 15 SP5 kernel.
2: boots a rescue kernel.

If you omit this specification, GRUB 2 is started after a timeout period has expired.

For a site specification, use one of the following values for <parm>:

S<n>: Specifies the site ID for which site-specific kernel parameters and DASD configurations are to be used. The site ID <n> is a digit in the range 0 to 9.
SS: Uses the subchannel set ID (SSID) of the IPL device as the site ID, for example, if the SSID is 0, values for site 0 are used.
S: Uses the common specifications. Specifying a single capital S without a trailing site ID is equivalent to omitting the S parameter.

For more information about site-specific configurations, see Site-specific Linux instantiation.

-b <n> or --bootprog <n>

For SUSE Linux Enterprise Server 15 SP5 in LPAR mode or as a z/VM guest with a SCSI boot device or an NVMe device, you can specify 0, 1, or 2

0 or 1: immediately starts GRUB 2 for booting the target SUSE Linux Enterprise Server 15 SP5 kernel.
2: boots a rescue kernel.

If you omit this specification, GRUB 2 is started after a timeout period has expired.

-p or --bootparms

specifies boot parameters for the next reboot. The boot parameters, which typically are kernel parameters, are appended to the kernel parameter line in the boot configuration. The boot configuration can include up to 895 characters of kernel parameters. The number of characters you can specify in addition for rebooting depends on your environment and re-IPL device as shown in Table 1.

Table 1. Maximum characters for additional kernel parameters by re-IPL device
Environment	DASD	SCSI or NVMe	NSS
z/VM	64	3452	56
LPAR	none	3452	n/a
KVM	none	n/a	n/a

Notes:

The kernel parameters that you specify for a DASD or NSS re-IPL device are stored with the z/VM PARM parameter.
The kernel parameters that you specify for a SCSI re-IPL device are stored as SCPDATA.

If you omit this parameter, the existing boot parameters in the next boot configuration are used without any changes.

Important: If the re-IPL kernel is SUSE Linux Enterprise Server 12 or later, be sure not to specify kernel parameters that prevent the target kernel from booting. See Avoid parameters that break GRUB 2.

-f or --force

With this option, you can force the re-IPL from a target device even if the target cannot be verified by the system. This is the case, for example, if the device is on the cio_ignore exclusion list.

Note: Use this option with great care. Specifying a non-existing device causes the re-IPL to fail.

-h or --help

displays help information for the command. To view the man page, enter man chreipl.

-v or --version

displays version information.

For disk-type re-IPL devices, the command accepts but does not require an initial statement:

ccw: declares that the following parameters refer to a DASD or a virtio block re-IPL device.
fcp: declares that the following parameters refer to a SCSI re-IPL device.
node: declares that the following parameters refer to a disk re-IPL device that is identified by a device node or by a directory in the Linux file system on that device. The disk device can be a DASD or a SCSI disk.

Examples

These examples illustrate common uses for chreipl.

The following commands all configure the same DASD as the re-IPL device, assuming that the device bus-ID of the DASD is 0.0.7e78, that the standard device node is /dev/dasdc, that udev created an alternative device node /dev/disk/by-path/ccw-0.0.7e78, that /mnt/boot is located on the Linux file system in a partition of the DASD.
- Using the bus ID:
```
# chreipl 0.0.7e78
```
- Using the bus ID and the optional ccw statement:
```
# chreipl ccw 0.0.7e78
```
- Using the bus ID, the optional statement and the optional --device keyword:
```
# chreipl ccw --device 0.0.7e78
```
- Using the standard device node:
```
# chreipl /dev/dasdc
```
- Using the udev-created device node:
```
# chreipl /dev/disk/by-path/ccw-0.0.7e78
```
- Using a directory within the file system on the DASD:
```
# chreipl /mnt/boot
```
The following commands all configure the same SCSI disk as the re-IPL device, assuming that the device bus-ID of the FCP device through which the device is attached is 0.0.1700, the WWPN of the storage server is 0x500507630300c562, and the LUN is 0x401040b300000000. Further it is assumed that the standard device node is /dev/sdb, that udev created an alternative device node /dev/disk/by-id/scsi-36005076303ffc56200000000000010b4, and that /mnt/fcpboot is located on the Linux file system in a partition of the SCSI disk.
- Using bus ID, WWPN, and LUN:
```
# chreipl 0.0.1700 0x500507630300c562 0x401040b300000000
```
- Using bus ID, WWPN, and LUN with the optional fcp statement:
```
# chreipl fcp 0.0.1700 0x500507630300c562 0x401040b300000000
```
- Using bus ID, WWPN, LUN, the optional statement, and keywords for the parameters. When you use the keywords, the parameters can be specified in any order:
```
# chreipl fcp --wwpn 0x500507630300c562 -d 0.0.1700 --lun 0x401040b300000000
```
- Using the standard device node:
```
# chreipl /dev/sdb
```
- Using the udev-created device node:
```
# chreipl /dev/disk/by-id/scsi-36005076303ffc56200000000000010b4
```
- Using a directory within the file system on the SCSI disk:
```
# chreipl /mnt/fcpboot
```
To configure a DASD with bus ID 0.0.7e78 as the re-IPL device, using 2 to select a boot option from the GRUB 2 boot menu:
```
# chreipl 0.0.7e78 -L 0g2
Re-IPL type:  ccw
Device:       0.0.7e78
Loadparm:     "0g2"
Bootparms:    ""
```
The following examples configures a DASD with bus ID 0.0.7e78 as the re-IPL device. To also display all kernel messages on the console, add ignore_loglevel to the existing kernel parameters in the boot configuration. To clear memory at the expense of a prolonged re-IPL procedure, set the clear mode to 1.
```
# chreipl 0.0.7e78 -p "ignore_loglevel" -c 1
Re-IPL type:  ccw
Device:       0.0.7e78
Loadparm:     ""
Bootparms:    "ignore_loglevel"
clear:        1
```

The following examples configures an NVMe device with Function ID 0x00000013 and name space ID 0x00000001 as the re-IPL device.

# chreipl nvme -i 0x13 -s 1
Re-IPL type: nvme
FID: 0x00000013
NSID: 0x00000001
bootprog: 0
br_lba: 0
Loadparm: ""
Bootparms: ""
clear:       0