Open Stack

Hi,

I would agree with Stan that we need to discuss definitions before going
deeply to the implementation.

The first example on the
https://wiki.openstack.org/wiki/Heat/Blueprints/hot-software-config shows
components like install_mysql and install_wordpress.
I would say that this is a bit confusing because I expected to see
component definitions instead of software deployment definition process. I
think this is a quite dangerous path here because this example shows us
that we can use components as installation steps definition instead of real
component definition.
If one continue to do this approach and defines more and more granular
steps as a components they will come to workflow definition composed in
terms of components. This approach does not add either simplicity or
clarity in the HOT template.

Thanks
Georgy



On Tue, Oct 22, 2013 at 10:02 AM, Stan Lagun <slagun at mirantis.com> wrote:

> Hello,
>
> I've been reading through the thread and the wiki pages and I'm still
> confused by the terms. Is there a clear definition of what do we understand
> by component from user's and developer's point of view. If I write
> "component, type:MySQL" what is behind that definition? I mean how does the
> system know what exactly MySQL is and how to install it? What MySQL version
> is it gonna be? Will it be x86 or x64? How does the system understand that
> I need MySQL for Windows on Windows VM rather then Linux MySQL? What do I
> as a developer need to do so that it would be possible to have "type:
> MyCoolComponentType"?
>
>
> On Tue, Oct 22, 2013 at 8:35 PM, Thomas Spatzier <
> thomas.spatzier at de.ibm.com> wrote:
>
>> Zane Bitter <zbitter at redhat.com> wrote on 22.10.2013 17:23:52:
>> > From: Zane Bitter <zbitter at redhat.com>
>> > To: openstack-dev at lists.openstack.org,
>> > Date: 22.10.2013 17:26
>> > Subject: Re: [openstack-dev] [Heat] HOT Software configuration proposal
>> >
>> > On 22/10/13 16:35, Thomas Spatzier wrote:
>> > > Zane Bitter <zbitter at redhat.com> wrote on 22.10.2013 15:24:28:
>> > >> From: Zane Bitter <zbitter at redhat.com>
>> > >> To: openstack-dev at lists.openstack.org,
>> > >> Date: 22.10.2013 15:27
>> > >> Subject: Re: [openstack-dev] [Heat] HOT Software configuration
>> proposal
>> > >>
>> > >> On 22/10/13 09:15, Thomas Spatzier wrote:
>> > >>> BTW, the convention of properties being input and attributes being
>> > > output,
>> > >>> i.e. that subtle distinction between properties and attributes is
>> not
>> > >>> really intuitive, at least not to me as non-native speaker, because
>> I
>> > > used
>> > >>> to use both words as synonyms.
>> > >>
>> > >> As a native speaker, I can confidently state that it's not intuitive
>> to
>> > >> anyone ;)
>> > >
>> > > Phew, good to read that ;-)
>> > >
>> > >>
>> > >> We unfortunately inherited these names from the Properties section
>> and
>> > >> the Fn::GetAtt function in cfn templates. It's even worse than that,
>> > >> because there's a whole category of... uh... things (DependsOn,
>> > >> DeletionPolicy, &c.) that don't even have a name - I always have to
>> > >> resist the urge to call them 'attributes' too.
>> > >
>> > > So is this something we should try to get straight in HOT while we
>> still
>> > > have the flexibility?
>> >
>> > Y-yes. Provided that we can do it without making things *more*
>> > confusing, +1. That's hard though, because there are a number of places
>> > we have to refer to them, all with different audiences:
>> >   - HOT users
>> >   - cfn users
>> >   - Existing developers
>> >   - New developers
>> >   - Plugin developers
>> >
>> > and using different names for the same thing can cause problems. My test
>> > for this is: if you were helping a user on IRC debug an issue, is there
>> > a high chance you would spend 15 minutes talking past each other because
>> > they misunderstand the terminology?
>>
>> Hm, good point. Seems like it would really cause more confusion than it
>> helps. So back away from the general idea of renaming things that exist
>> both in cfn and HOT.
>> What we should try of course is to give new concepts that will only exist
>> in HOT intuitive names.
>>
>> >
>> > > Regarding properties/attributes for example, to me I would call both
>> just
>> > > properties of a resource or component, and then I can write them or
>> read
>> > > them like:
>> > >
>> > > components:
>> > >    my_component:
>> > >      type: ...
>> > >      properties:
>> > >        my_prop: { get_property: [ other_component,
>> other_component_prop ] }
>> > >
>> > >    other_component:
>> > >      # ...
>> > >
>> > > I.e. you write property 'my_prop' of 'my_component' in its properties
>> > > section, and you read property 'other_component_prop' of
>> 'other_component'
>> > > using the get_property function.
>> > > ... we can also call them attributes, but use one name, not two
>> different
>> > > names for the same thing.
>> >
>> > IMO inputs (Properties) and outputs (Fn::GetAtt) are different things
>> > (and they exist in different namespaces), so -1 for giving them the same
>> > name.
>> >
>> > In an ideal world I'd like HOT to use something like get_output_data (or
>> > maybe just get_data), but OTOH we have e.g. FnGetAtt() and
>> > attributes_schema baked in to the plugin API that we can't really
>> > change, so it seems likely to lead to developers and users adopting
>> > different terminology, or making things very difficult for new
>> > developers, or both :(
>> >
>> > cheers,
>> > Zane.
>> >
>> > _______________________________________________
>> > OpenStack-dev mailing list
>> > OpenStack-dev at lists.openstack.org
>> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>> >
>>
>>
>> _______________________________________________
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>> OpenStack-dev at lists.openstack.org
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>>
>
>
>
> --
> Sincerely yours
> Stanislav (Stan) Lagun
> Senior Developer
> Mirantis
> 35b/3, Vorontsovskaya St.
> Moscow, Russia
> Skype: stanlagun
> www.mirantis.com
> slagun at mirantis.com
>
> _______________________________________________
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> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>
>


-- 
Georgy Okrokvertskhov
Technical Program Manager,
Cloud and Infrastructure Services,
Mirantis
http://www.mirantis.com
Tel. +1 650 963 9828
Mob. +1 650 996 3284
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