> A template is just a special type of compute resource and there's nothing to
> say we're not going to end up with template network and storage resources as
> well - I really don't think a new noun is justified and would prefer to keep
> things as simple as possible... 3 nouns is about right.
>
> Sam
I'm still warping^H^H^H^H^H wrapping my head around RESTful thinking
as opposed to OO, so please bear with me.
That's ok... in fact RESTful interfaces are usually fairly OO - what I call ROA is just taking it to the extreme. Most people are still thinking like functional programming (e.g. RPC-style), as reflected in APIs like Amazon EC2.
If both "AMI"s (template-computes) and "instances" (actual-computes)
are "compute" resources, then how would the client distinguish between
the two? One reason to distinguish between them is to separately
classify them into different areas of the UI (for example the "Images"
vs. Instances" tabs of ElasticFox) based on the verbs that can be done
to them.
The simplest solution for this is to add templates to a "template" category. In fact we could specify a number of well known categories like "validated", "[in]secure", etc.
On second thought, I may have answered my own question: we can
distinguish template-computes from actual-computes by looking at the
verb links that are provided on them. Actual-computes will have verbs
such as "start","stop", "pause", "resume", "delete" (depending on
their current state); while template-computes will only have "start"
and "delete", and their state will never change (not sure, but it
seems to me that a template's state will not change - you can only
create a new resource from a template or delete the template
altogether).
Exactly, only there may be conditions where machines in transition or in abnormal/error states appear as templates when they should not. I'm not yet sure whether we need to explicitly state that a machine is a template (or just rely on the presence or absence of verbs like "clone" and "start" respectively)... but I am sure that they are the same noun.
Then again, if an infrastructure provider does not allow
actual-computes to be "paused" or "resumed" but does allow "start" and
"stop", then we cannot distinguish between actual-computes that are
stopped (having verbs "start" and "delete") and between
template-computes (having verbs "start" and "delete").
Right. It's also possible that user permissions will confuse things - perhaps a failover operator can start but not stop machines for example.
So then the question remains: how do we reliably distinguish between
template-computes and actual-computes? Or template-XXs and actual-XXs
?