Background: Introduction to Xen PV Bootloaders
In the very early days of Xen it was necessary for the host (domain 0)
administrator to explicitly supply a kernel (and perhaps initial
ramdisk) from the domain 0 filesystem in order to start a new guest.
This mostly worked and for some use cases, i.e. those where the host
admin wants very strict control over what each guest runs, was
desirable and remains so today.
However for other use cases it was rather inflexible since it meant
that the host administrator needed to be involved in what many
considered to be a guest administrator, or even distribution level,
decision i.e. the selection of which kernel to run, with what
parameters etc. Continue reading