----- Original Message -----
From: "Ayal Baron" <abaron@redhat.com> To: "Livnat Peer" <lpeer@redhat.com> Cc: engine-devel@ovirt.org Sent: Tuesday, January 17, 2012 11:45:33 AM Subject: Re: [Engine-devel] the future of template cloning
----- Original Message -----
On 17/01/12 10:46, Itamar Heim wrote:
On 01/17/2012 10:32 AM, Omer Frenkel wrote:
----- Original Message -----
From: "Itamar Heim"<iheim@redhat.com> To: "Jon Choate"<jchoate@redhat.com> Cc: engine-devel@ovirt.org Sent: Monday, January 16, 2012 7:26:24 PM Subject: Re: [Engine-devel] the future of template cloning
On 01/16/2012 06:16 PM, Jon Choate wrote:
On 01/16/2012 10:58 AM, Itamar Heim wrote: > On 01/16/2012 05:46 PM, Jon Choate wrote: >> On 01/16/2012 09:46 AM, Livnat Peer wrote: >>> On 12/01/12 22:45, Ayal Baron wrote: >>>> >>>> ----- Original Message ----- >>>>> We are going to be able to store the disks for a template >>>>> on >>>>> different storage domains due to the multiple storage >>>>> domain >>>>> feature. Cloning a template will still be possible, but >>>>> will >>>>> it >>>>> provide any value? Thoughts? >>>> I see no relation between the two options. >>>> >>>> Scenario 1: I can create a VM with a single disk and >>>> create >>>> a >>>> template from it. >>>> I would still want to be able to clone the template in >>>> order >>>> to >>>> provision VMs from it on different domains. >>>> >>>> Scenario 2: same thing with multiple disks on same domain. >>>> >>>> Scenario 3: I have a template with 2 disks on 2 different >>>> domains >>>> (domain A and domain B) and I want to have another copy of >>>> the >>>> template on domain C and domain D >>>> >>> Hi Jon, >>> >>> After talking to Michael Pasternak it seems that we did not >>> implemented >>> copyTemplate in the REST API, it seems to be a gap that we >>> have. >>> >>> This gap is playing in our favor, we can remove the >>> copyTemplate >>> verb >>> and introduce copyDisk verb. >>> >>> The template disks can be copied to another SD. >>> When creating a VM from template the user can choose per >>> disk >>> the >>> destination SD (only SD with the disks are eligible >>> candidates). >> wait, when creating a VM from a template, the user won't get >> a >> choice >> will they? Won't the VM disks have to go on the same storage >> domain as >> the template disks they were created from? > > yes, but the template disks can be copied to multiple storage > domains, > so the user can choose for the VM/disk which storage domain > to > create > them from (per storage domains that have copies of that disk) OH! I totally misunderstood. So what you are saying is that a template can have N number of copies of the same disk each on a different storage domain. I had thought that if you wanted that type of situation you would have multiple copies of the template itself too.
yes, one copy of disk per domain though.
Just to be clear, does this mean that the plan is to phase out the current clone template command and instead implementing a clone disk command so that a template can duplicate its disks individually?
pretty much, yes. though i'd imagine 'clone template' would still be useful to have for the user. not sure if it implies core should expose it as well to allow easier usage at UI level for such a task.
we can leave it untouched - means copyTemplate get 1 destination domain, and copies all disks to it, but i think it will be unusable (and problematic - what if one of the disks already exists on the destination?),
then don't copy it, it is already there
I agree with Omer, there is no reason to support copy template, if the user wants to clone all the disks he can use multiple actions, we don't need a specific verb for this.
Reason or lack of depends on the common usage. If we assume that normally all disks of a template would reside on the same domain then it makes sense to have a verb to copy the template in its entirety and not burden the user. The general recommendation should be to use a single storage domain, so I think there is room for such a verb. I agree. This is the common use case, all disk resides on the same SD. and that is why we need a verb for it. However, for more "trick"/special cases we need to support multi domains. I also think it would be easier from api perspective to use a single copy verb.
If the UI chooses to expose such operation it will use the multipleRunAction API which makes it easier to expose to the user partial success, we could clone disk A and Disk B but Disk C failed etc.
The multipleRunAction is for user marking multiple objects in GUI and running an action on all of these objects. Here however, the action the user wants is to copy 1 object (the template) which has sub objects and it should run as a single action. For example, if there is enough space on the target domain for 2/4 disks then using multipleRunAction would result in 2 disks being copied and 2 failing. If however it is a single action then the free space test would fail the entire action and user would be able to choose if he wants to copy just 2. Note that in this case, actually performing the copy of the 2 disks is detrimental as it can negatively affect VMs on this domain.
what the user really wants is to specify which disks to copy and destination per disk, and i don't see a reason to create a backend command to do it
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
_______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel