Re: block-nbd script and example config

[Anthony Liguori <aliguori@us.ibm.com>]

Nicholas Lee wrote:

>>The only thing to think about is how do handle file devices with spaces
>>in the filename.  This is going to be common I think.
>>    
>>
>
>Since it's a python variable can't you just run a validator on config
>import and throw an exception if the devive block doesn't exist. 
>Noting that device paths including special characters need to be
>enclosured in "...".
>
>ie. export=phy:"/dev/vgname/bob your uncle; mate! device", ...
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>
Double quotes are actually valid characters in a filename although 
rarely used.

A more bold way of approaching this would be to adopt a more qemu like 
syntax of:

hda1="/dev/vgname/bob you uncle; mate1"
hda2="/root/rockhopper.img"

We could use stat to figure out whether something was a file or a device 
and use the appropriate script (file or phy).  For everything else, we 
could use explicit urls such as:

hda3="nbd://rockhopper.austin.ibm.com:1025"

I like the syntax a lot but I'm not sure that marking a device read-only 
works nicely anymore.  We could have a single readonly attribute like:

readonly=['hda1', 'hda2']

Or perhaps just require url encoding:

hda1="phy:///dev/vgname/bob you uncle&readonly=1"

Kind of ugly but at least we're optimizing for the common case.

Just thinking out loud.

Regards,

Anthony Liguori

>--
>Nicholas Lee
>http://stateless.geek.nz
>gpg 8072 4F86 EDCD 4FC1 18EF  5BDD 07B0 9597 6D58 D70C
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