[et-mgmt-tools] Re: [PATCH] virt-install cli options for managed storage

[Daniel P. Berrange]

On Tue, Aug 12, 2008 at 05:06:38PM -0400, Cole Robinson wrote:
> Per Dan's advice, I've changed the previously proposed
> virt-install cli options for specifying libvirt managed
> storage.
> 
> This patch does not change any possible semantics of
> --file or --cdrom: they remain strictly for specifying
> local media. In this way they are basically deprecated.
> 
> A new cli option is added: --disk. The format is:
> 
> --disk  path:///some/file/path[:device=cdrom|floppy][:permissions=ro|sh]
> --disk  vol:///poolname/volname[:device=cdrom|floppy][:permissions=ro|sh]
> --disk  pool:///poolname[:device=cdrom|floppy][:permissions=ro|sh]
> 
> The changes from Dan's proposal are:
> 
>  - use of path:/// instead of file:///, since this will
>    hopefully clear up any confusion users previously had
>    with specifying block devices.
>  - For vol:///, I used / as a delimiter vs. ':' between
>    the pool and vol name, to avoid any extra collisions
>    (since I assume '/' is not part of a legal pool name).
>  - Explictly list what type of extra option we are
>    appending (device, permissions). This adds clarity
>    to the command line, reduces chance of name collision,
>    and is similar to the approach used by qemu.
> 
> The --disk option is quite useful even for the local case,
> since users can now add cdrom and floppy drives (and eventually
> other device types) via the cli. This could also be expanded
> to allow specifying file formats (qcow2, etc.) for creating
> new storage.
> 
> The other functionality change is that disk:/// can be used
> to specify install media. If none of --pxe, --cdrom, or 
> --location are specified, we look to see if a --disk 
> device=cdrom was specified, and if so, use that for
> installation. We can eventually expand this to allow
> installing off floppies.
> 
> One question: Is ':' an appropriate delimiter? qemu typically
> uses ',' for these types of cli options. May be an arbitrary
> choice, but perhaps someone has an opinion.

You could use ',', or we could use full URI syntax 

  vol:///poolname/volname?device=[cdrom|floppy][;permissions=ro|sh]

Separating params by a ';' or '&' - the former avoids shell
metacharacter expansion

Daniel
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