[libvirt] Add pool to domain xml
(Renamed subject from [PATCH] Support transient attribute on vmware disks)
On Dec 27, 2013, at 22:59 , Eric Blake <eblake(a)redhat.com> wrote:
On 12/27/2013 02:40 PM, Wout Mertens wrote:
>
> Otherwise it seems to me that this would be part of the general section, perhaps
simply a “path” node?
Not quite a path node. I was thinking more like:
<domain type='kvm'>
<name>foo</name>
<pool name='mypool'/>
...
where the new <pool> element says that anything that the 'foo' domain
does that requires creation of new files will do so within the already
existing <pool> object with the name 'mypool'. We can also support
<pool uuid='...'> (or both name and uuid at once). If the <pool>
element is missing, that's when the domain uses defaults and/or refuses
to do tasks where we don’t know where to stick the files.
Yes, that seems like a nice interface. It does throw away some info (the full path to the
.vmx file in the case of VMWare) but that doesn’t really matter very much.
I had a look at implementing this but I’m stuck. I don’t know the code very well, I figure
there are at least three places this impacts (for vmware):
- (1) the virDomainDef definition
- (2) the translation from virDomainDef to .vmx file path
- (3) (optionally I suppose) the translation from .vmx file to virDomainDef
For (1), I added a sub-struct to _virDomainDef in domain_conf.h:
struct {
char *name;
char *uuid;
} pool;
…thinking this would be easier than managing a pool object pointer and a more direct
representation of the domain xml. Is there any change to definition or initialization code
etc needed elsewhere? Testing code?
For (2): The translation from virDomainDef to path happens in
vmware_conf.c:vmwareVmxPath() and there the problem is that regular VMWare uses a full
path but ESX uses the ‘[storage] ‘ prefix instead.
- I presume there’s somewhere in the pool management code that translates this, any
pointers?
- vmware_conf.c then needs to pull in the storage_conf.h file, is that a problem?
- I propose that if both UUID and name are present, UUID takes precedence over name, but
if no device is found then name is tried.
I haven’t tackled (3) yet and I suppose it doesn’t really add much, certainly not for my
use case.
Happy 2014! :)
Wout.