Xenserver/citrix hypervisor and xcp-ng blank screen while loading the installer

While performing maintenance on my lab environment i encounterd a strange problem with the installation process for Xenserver 8.2 (and 8.1/8.0). Starting the installer will result in ether a black screen or a kernel panic.

After some research i found an interesting issue in github (from the xcp-ng project) https://github.com/xcp-ng/xcp/issues/206.

It remains unclear why the installation was unable to start, but it looks like some cpu+mainbord combinations are unable to handle the default maxmem setting of 8192MB. changing the Maxmem setting on the USB boot drive will allow the installation to start.

If you use UEFI to boot, you will need to edit the file: USB:\EFI\xenserver\grub.cfg

Find the following sniped (starting from line 19 on my Xenserver 8.2 image).

menuentry "install" {
    multiboot2 /boot/xen.gz dom0_max_vcpus=1-16 dom0_mem=max:8192M com1=115200,8n1 console=com1,vga
    module2 /boot/vmlinuz console=hvc0 console=tty0
    module2 /install.img
}

And change it to:

menuentry "install" {
    multiboot2 /boot/xen.gz dom0_max_vcpus=1-16 dom0_mem=max:2048M com1=115200,8n1 console=com1,vga
    module2 /boot/vmlinuz console=hvc0 console=tty0
    module2 /install.img
}

If you use LEGACY boot, you wille need to edit the file: USB:\boot\isolinux\isolinux.cfg

Find the following sniped (starting from line 19 on my Xenserver 8.2 image).

LABEL install
	KERNEL mboot.c32
	APPEND /boot/xen.gz dom0_max_vcpus=1-16 dom0_mem=max:8192M com1=115200,8n1 console=com1,vga --- /boot/vmlinuz console=hvc0 console=tty0 --- /install.img

And change it to:

LABEL install
	KERNEL mboot.c32
	APPEND /boot/xen.gz dom0_max_vcpus=1-16 dom0_mem=max:2048M com1=115200,8n1 console=com1,vga --- /boot/vmlinuz console=hvc0 console=tty0 --- /install.img

Your Xenserver / xcp-ng installation should now work 🙂