Re: Dracut generation modes

[Seewer Philippe <philippe.seewer-omB+W0Dpw2o@public.gmane.org>]

Warren Togami wrote:
> So this might not have been clear earlier, but stating it on the list to 
> be sure everyone is on the same page.
> 
> * Default Dracut
> Dracut without any parameters should generate an initrd image capable of 
> booting a generic machine.  This means it must not detect anything of 
> the current running system to determine what to install in the image. 
> This includes stuff in /proc, /sys, lsmod, /proc/mounts and possibly more.

Yes

> 
> By necessity, stuff in the filesystem are usable to dracut in 
> determining what to install in the image.

...Dracut has to get it's tools from somewhere...

> 
> * --hostonly mode
> Host only mode is permitted to use runtime detection to generate an 
> image capable of booting the current system.  What exactly does this 
> mean?  Is this primarily for smaller sizes by avoiding irrelevant modules?

Yes. And possibly more optimization. I'm thinking "apt-get update 
linux-image" which automatically rebuilds the initrd...

> * (Some other generation mode)
> Perhaps we need more generation modes for other purposes.  One likely 
> case is where you need to generate a machine specific image for a 
> non-local system.  A combination of command line options and/or .conf 
> file would define the dracut image for a non-local system.  This might 
> be necessary for cases like:
> 
> - netboot initrd needs to be as small as possible for resource 
> constraint reasons
> - embedded systems with resource constraints

That's what dracutmodules in the configfile is for.

> - certificates or passwords for iscsi or kerberized nfs

I'd say either via injection or a site-specific add-on module.

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