Thanks a lot Justin for such a
detailed explanation.
> If the domain has an XML definition
for it in place, the "Destroy"
> command won't touch it. You can start the domain again using the
> "Create" function:
>
> http://libvirt.org/html/libvirt-libvirt.html#virDomainCreate
>
> If you want to get rid of an XML definition for the domain from a
> server, the command you're looking for is "undefine":
>
> http://libvirt.org/html/libvirt-libvirt.html#virDomainUndefine
> command won't touch it. You can start the domain again using the
> "Create" function:
>
> http://libvirt.org/html/libvirt-libvirt.html#virDomainCreate
>
> If you want to get rid of an XML definition for the domain from a
> server, the command you're looking for is "undefine":
>
> http://libvirt.org/html/libvirt-libvirt.html#virDomainUndefine
I understood now what the destroy function
does. As for "domainUndefine":
To quote from the "undefine"
method's documentation:
Undefine a domain but does not stop it
if it is running
So, If the Domain remains as it
is, what is the significance of removing the XML
Description/Definition?
What I want to do, is to remove the Domain
completely from the system, including its associated virtual disks. Is
there any way to do this using the API?
>> Secondly, Is it possible to boot
a domain on a completely different physical
>> host with the same Hypervisor configuration?
>
> You can use libvirt for this, but it's not automatic. As far as I know,
> you'll need to have your software connect to each of the servers and
> launch the appropriate virDomainCreate() (and probably other) commands.
> So, it would be up to your application to make sure that the domain is
> not running on server A, before you launch it on server B.
>> host with the same Hypervisor configuration?
>
> You can use libvirt for this, but it's not automatic. As far as I know,
> you'll need to have your software connect to each of the servers and
> launch the appropriate virDomainCreate() (and probably other) commands.
> So, it would be up to your application to make sure that the domain is
> not running on server A, before you launch it on server B.
I am sorry, but I did not get this quite
completely. Could you please explain this a bit more? Especially the "it
would be up to your application to make sure that the domain is
not running on server A, before you launch it on server B" part. Firstly, how will I get the domain from server A to server B to launch it there? By migrating it to server B?
not running on server A, before you launch it on server B" part. Firstly, how will I get the domain from server A to server B to launch it there? By migrating it to server B?
Please help.
Thanks and Regards
Sagar Barve
Sagar Barve
----- Original Message -----
From: "Justin Clift" <justin@xxxxxxxxxxxx>
To: "IKI-サガル バルウェ" <sagar.barve@xxxxxxxxxx>
Cc: <libvir-list@xxxxxxxxxx>
Sent: Thursday, June 17, 2010 5:17
PM
Subject: Re: 1. Domain Destroy ,
2. Domain boot on a different host and 3. Domain start time
>> Hello,
>>
>> Firstly, I have some confusion about the libvirt API "virDomainDestroy"
>> method. here is the link to API:
>> http://libvirt.org/html/libvirt-libvirt.html#virDomainDestroy
>
> "Destroy" here can be a bit confusing. It doesn't really touch or
> remove the disk data. "Destroy" in this case means to destroy just the
> running instance of the domain. i.e. stop running it, free up the
> memory that was allocated to it, and free up any devices (network
> resource, etc) that had been assigned to it.
>
> If the domain has an XML definition for it in place, the "Destroy"
> command won't touch it. You can start the domain again using the
> "Create" function:
>
> http://libvirt.org/html/libvirt-libvirt.html#virDomainCreate
>
> If you want to get rid of an XML definition for the domain from a
> server, the command you're looking for is "undefine":
>
> http://libvirt.org/html/libvirt-libvirt.html#virDomainUndefine
>
>
>> Secondly, Is it possible to boot a domain on a completely different physical
>> host with the same Hypervisor configuration?
>> For. E.g: if I have a domain on a host 192.168.101.1 running Xen with a
>> Domain "test" in shutdown state. If I have to start/boot the domain "test"
>> on a different physical host, running Xen say 192.168.101.2, is it possible
>> using libvirt API? If not, then is there any other method to do it?
>
> You can use libvirt for this, but it's not automatic. As far as I know,
> you'll need to have your software connect to each of the servers and
> launch the appropriate virDomainCreate() (and probably other) commands.
> So, it would be up to your application to make sure that the domain is
> not running on server A, before you launch it on server B.
>
>
>> Thirdly, Is there a method to get the total running time of a domain? I
>> mean, the amount of time since the domain had been booted. Currently, I can
>> fetch the CPU time. But, is this the exact amount of time the domain is ON?
>> i.e. If the domain is in a "IDLE" state, the CPU time does not increase. But
>> what I want is the amount of time the domain was ON(including the idle
>> time). So, If I can get the start time of the domain, I can calculate the
>> duration.
>
> Sorry, I personally can't help with this one. I haven't had to look at
> this stuff yet.
>
> Hope the above stuff helps though. :)
>
> Regards and best wishes,
>
> Justin Clift
>
> --
> Salasaga - Open Source eLearning IDE
> http://www.salasaga.org
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