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virt-install : ERROR the CPU is incompatible with host CPU: unknown host CPU



While installing operating system using the command virt-intsll or libvirt we might encounter the above error. The error might occur even if the cpu model is a popular one.

In some forums it is mentioned that this error could be because nx/xd feature of the CPU is not enabled, but some BIOS don't have this nx/xd feature at all making it very difficult to change or verify it.
The only work around that helped was using the cpu as "clear cpu configuration". That is while running the virt-install command pass the option "clear" for --cpu as shown below.



If you are using libvirt then the option is available under hardware details->processor as shown in the figure below.


Setting this option might help get around the error.


use isoinfo to find if an iso image is bootable

Using iso images for installation is a common practice. But some isos might fail to boot when we try to use them. One of the reasons could be that the iso is not a bootable iso. One way to verify if the iso is bootable or now is to use the isoinfo command in linux.

isoinfo is a command that provides a lot of information regarding an iso file.



To view the information about whether the iso is bootable or not use the option -d.



From the above output we can see that the iso has an Eltorito boot loader, thus it is a bootable iso. If the iso does not have a boot loader we would not see any boot loader information in the output of the above command.

We can also use the isoinfo command to list the contents of the iso usin the option -l