Comment 35 for bug 1859656

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Andrew Cloke (andrew-cloke) wrote : Re: [2.6] Unable to reboot s390x KVM machine after initial deploy

After discussing, I realise I had a misunderstanding in comment #30 that I'd like to correct.

I had incorrectly assumed that feeding the PXEBooting KVM guest a zero length pxelinux.cfg file *instructed* it to boot from the local disk.

I now realise that is incorrect. Feeding the PXEBooting KVM guest a zero length pxelinux.cfg file only tells the guest to *fail* it's netboot attempt.

It's at this stage that the architecture specific behaviour kicks in.

On amd64, the netboot failure will force the KVM guest to move down to it's second specified boot option, namely the local disk.

However, s390x will NEVER move to it's second specified boot option. If the first boot option (netbooting) fails, it abandons the attempt and powers the guest off.

IBM has been informed of this difference in behaviour, but it is unlikely to be able to address it soon.