Features/S390xNetworkBoot: Difference between revisions
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== Overview == | == Overview == | ||
The network boot feature enhances the s390x ipl device and the s390-ccw bios with support for booting via a virtio-net boot device. A new address is added to the ccw ipl block providing the address of a s390-netboot.img which performs the actual load over the network. This code | The network boot feature enhances the s390x ipl device and the s390-ccw bios with support for booting via a virtio-net boot device. A new address is added to the ccw ipl block providing the address of a s390-netboot.img (effectively a network boot ROM) which performs the actual load over the network. This code has been included into QEMU since 2.9. | ||
== Building s390-netboot. | Starting with 2.10 QEMU includes a pre-built network boot ROM based on the SLOF firmware, enabling network booting from a DHCP/TFTP server. As s390 network bootable operating system images are not very common at this point in time, this document also gives a brief overview on how to build one. | ||
== Booting from a network interface == | |||
The network boot can't be triggered using the traditional ''-boot n'' command line option, but requires to specify the ''bootindex'' attribute on the network device. E.g., | |||
qemu-system-s390x ... -device virtio-net-ccw,netdev=hostnet0,id=net0,bootindex=1 | |||
or, with libvirt | |||
... | |||
<interface type='network'> | |||
<source network='default'/> | |||
<model type='virtio'/> | |||
<boot order='1'> | |||
</interface> | |||
... | |||
== Building a s390 network bootable binary == | |||
A s390 operating system image usable for network booting can be built from an initial ramdisk and a kernel image. These can be taken from any existing s390 system. | |||
One way to build an image is to take a kernel and an installer initial ramdisk from a distribution's DVD/ISO and concatenate them. Some fixups are necessary in the new binary. Both, concatenation and fixups can be done by using the script in [https://github.com/ibm-s390-tools/s390-tools/blob/master/netboot/mk-s390image]. Booting the resulting image would then start the installation process as if booted from the DVD. | |||
Another possible way is to build a binary that behaves similar to the PXELINUX boot loader. In this case an initial ramdisk with an init process triggering the PXELINUX-like processing has to be built as described in [https://github.com/ibm-s390-tools/s390-tools/tree/master/netboot]. The site also contains a script assisting in the creation of such an initial ramdisk. | |||
Latest revision as of 17:48, 15 April 2020
This is a short overview about using network boot for s390x.
Overview
The network boot feature enhances the s390x ipl device and the s390-ccw bios with support for booting via a virtio-net boot device. A new address is added to the ccw ipl block providing the address of a s390-netboot.img (effectively a network boot ROM) which performs the actual load over the network. This code has been included into QEMU since 2.9.
Starting with 2.10 QEMU includes a pre-built network boot ROM based on the SLOF firmware, enabling network booting from a DHCP/TFTP server. As s390 network bootable operating system images are not very common at this point in time, this document also gives a brief overview on how to build one.
Booting from a network interface
The network boot can't be triggered using the traditional -boot n command line option, but requires to specify the bootindex attribute on the network device. E.g.,
qemu-system-s390x ... -device virtio-net-ccw,netdev=hostnet0,id=net0,bootindex=1
or, with libvirt
...
<interface type='network'>
<source network='default'/>
<model type='virtio'/>
<boot order='1'>
</interface>
...
Building a s390 network bootable binary
A s390 operating system image usable for network booting can be built from an initial ramdisk and a kernel image. These can be taken from any existing s390 system.
One way to build an image is to take a kernel and an installer initial ramdisk from a distribution's DVD/ISO and concatenate them. Some fixups are necessary in the new binary. Both, concatenation and fixups can be done by using the script in [1]. Booting the resulting image would then start the installation process as if booted from the DVD.
Another possible way is to build a binary that behaves similar to the PXELINUX boot loader. In this case an initial ramdisk with an init process triggering the PXELINUX-like processing has to be built as described in [2]. The site also contains a script assisting in the creation of such an initial ramdisk.