Re: How to have dracut conditionally add different kernel modules for different kernels?

[Andrei Borzenkov <arvidjaar-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

В Fri, 10 Apr 2015 12:11:53 -0700
lyndat3-p/IIKWkZnU0S+FvcfC7Uqw@public.gmane.org пишет:

> The distro I use, opensuse, has switched to using dracut for initrd creation.
> 
> Prior to dracut usage, kernel-flavor-specific loading -- particularly for the case of Xen -- could be defined in
> 
>  /etc/sysconfig/kernel
>   ...
>   INITRD_MODULES="processor thermal ahci fan jbd ext3 edd"
>   DOMU_INITRD_MODULES="xennet xenblk"
>   ...
> 
> On 'old' mkinitrd, if both -xen and non-xen kernels were installed, initrd's were created for each.  In the xen case the modules defined in "DOMU_INITRD_MODULES" were conditionally added to the initrd-xen.
> 
> Since the  switch to dracut, module config/loading is defined in dracut.conf & dracut.d/*conf
> 
> But the 
> 
> add_drivers+=" ... " 
> 
> is apparently added for all kernels.
> 
> What's the right way to add kernel-specific modules in dracut, so that for example the xen mods are ONLY added in the xen case?

Not sure about the "right" way, but dracut configuration files are
shell scripts, so you can implement the same logic in /etc/dracut.d
snippet, something like

if is_xen_kernel ; then
  add_drivers+=" ..."
fi

where is_xen_kernel does whatever check is required to detect domU
kernel.