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From Sam Corbett <sam.corb...@cloudsoftcorp.com>
Subject Re: JcloudsLocation behaviour
Date Tue, 16 Jun 2015 11:19:21 GMT
Hi Svet

Thanks for your comments.

Re provision mode vs. byon locations:

A BYON location isn't incorporated into the rest of Brooklyn's 
lifecycle, so for example you couldn't destroy the instance when 
stopping the associated Brooklyn entity. (Correct me if I'm wrong or out 
of date!) Of more interest is that a BYON location cannot create an 
instance if the target does not exist (i.e. the rebind or obtain mode). 
Within a single deployment it might seem strange that a user might not 
know whether their location exists or not but it makes more sense if we 
attempted to handle such a case across many deployments of the same 
blueprint.

Perhaps simply starting with "obtain" and "rebind" is sufficient. If 
there is demand for "rebind or obtain" it will be straightforward to 
include later.

Re stop vs destroy:

I think it's as much to do with how users understand what "stop" means 
to Brooklyn as much as how useful the proposed functionality is. Stop 
and unmanage works but is unintuitive.

Sam

On 15/06/2015 12:18, Svetoslav Neykov wrote:
> Hi Sam,
> Could you describe what this approach gives in comparison with BYON location. In what
cases should the one or the other be preferred. Or does this supersede BYON?
>
> Re stop vs destroy - If I've ever had a need to manage a machine outside of Brooklyn
in any way I stop the process  and then unmanage the entity. Adding the functionality to the
STOP effector still has benefits, but no opinion about it. What I'd like to note is that when
adding it we should do it in a backwards compatible way. Currently stopMachineMode will destroy
the machine so we should keep it that way in case destroyMachineMode is not set.
>
> Svet.
>
>
>
>> On 11.06.2015 г., at 14:24, Sam Corbett <sam.corbett@cloudsoftcorp.com> wrote:
>>
>> Hi all,
>>
>> A couple of ideas for JcloudsLocation.
>>
>> I'd like to make it possible to incorporate existing machines into Brooklyn
>> as Jclouds locations rather than bring-your-own-node locations. To do this
>> I'd like to add a new config key, named something like "provision mode".
>> Valid options are:
>> * obtain: The current behaviour. Always provisions a new machine.
>> * rebind: Attempt to rebind to an existing machine using the location
>> properties and entity's provisioning properties. Fail if no suitable
>> machine is found.
>> * rebind or obtain: As rebind but calling `obtain` rather than failing if
>> no existing machine is found.
>>
>> Deployments would fail if an existing machine was found but Brooklyn cannot
>> connect to it.
>>
>> To aid the rebind cases I would add a second config key that sets the
>> predicate used to determine whether an existing machine should be used. The
>> current predicate
>> (brooklyn.location.jclouds.JcloudsLocation.RebindToMachinePredicate)
>> cross-checks IDs and hostnames. An obvious extension would be to look at a
>> machine's tags.
>>
>> I think this would be beneficial for users that want to bring existing
>> systems under Brooklyn's control.
>>
>> Second, when stopping entities is there any way to distinguish between
>> stopping and destroying their locations? The stop effector currently
>> accepts "stopProcessMode" and "stopMachineMode" arguments. I'm wondering if
>> there's a case for a third argument named "destroyMachineMode" (with values
>> always/never/if-not-stopped) that allows the caller to distinguish between
>> suspending and destroying instances.
>>
>> Any thoughts?
>>
>> Thanks,
>>
>> Sam
>>
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>> Registered Office: 13 Dryden Place, Edinburgh, EH9 1RP
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-- 
Cloudsoft Corporation Limited, Registered in Scotland No: SC349230. 
 Registered Office: 13 Dryden Place, Edinburgh, EH9 1RP
 
This e-mail message is confidential and for use by the addressee only. If 
the message is received by anyone other than the addressee, please return 
the message to the sender by replying to it and then delete the message 
from your computer. Internet e-mails are not necessarily secure. Cloudsoft 
Corporation Limited does not accept responsibility for changes made to this 
message after it was sent.

Whilst all reasonable care has been taken to avoid the transmission of 
viruses, it is the responsibility of the recipient to ensure that the 
onward transmission, opening or use of this message and any attachments 
will not adversely affect its systems or data. No responsibility is 
accepted by Cloudsoft Corporation Limited in this regard and the recipient 
should carry out such virus and other checks as it considers appropriate.

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