Re: Use & impact of role/host attribute in ARIA

2017-09-07 Thread Tal Liron 
Really, the only important one is "host" role. For the TOSCA get_property
and get_attribute functions there is support for a keyword called "HOST",
which explicitly follows the path of outbound relationships to Container
capabilities (there might be several) to the final Compute node. So
Container and Compute play special roles in TOSCA.

A related role is "feature" which exists for the tosca.capabilities.Node
(note: for the capability type, not the node type!). This is followed for
*inbound* relationships to find the "HOST". This is that nodes that have
relationships to the "feature" capability of any other node (it is declared
in tosca.nodes.Root) would be able to find their host.

There are a few other roles for ARIA-specific extensions: plugins,
workflows, and scaling policies.

We could have solved this by looking for hardcoded type names, but as I
said it seemed like a bad idea to me. As the TOSCA spec changes, these
names might change or their might be other ways to reach hosts. The "role"
keeps things generic and untied to the spec.


On Thu, Sep 7, 2017 at 3:06 AM, D Jayachandran 
wrote:

> Hi Tal,
>
> How do we conclude certain normative types play "special roles" ? I will
> wait for Ran to explain on the remove execution part.
>
>
> Regards,
> DJ
>
> -Original Message-
> From: Tal Liron [mailto:t...@cloudify.co]
> Sent: Wednesday, September 06, 2017 7:05 PM
> To: dev@ariatosca.incubator.apache.org
> Subject: Re: Use & impact of role/host attribute in ARIA
>
> First of all, "role" is an extension and is only used internally. It is
> indeed not defined by TOSCA and you shouldn't be using it yourself.
>
> The reason "role" exists is to avoid hardcoding functionality to type
> names. Certain normative types play special roles in TOSCA: certain
> relationships are special, as are certain capabilities, data types, etc. In
> order to avoid having ARIA look for a specific type name, it checks the
> "role" extension. Internally, "role" is inherited (and can be overridden),
> so that anything that inherits from tosca.nodes.Compute, for example, would
> also have the "host" role. (For past versions of the NFV Profile, we likely
> had the VDU type as having "host" role, even though it did not inherit from
> tosca.nodes.Compute).
>
> Then execution plug tries to find out if the operation is hosted remotely
> by seeing if the node is hosted: either a host itself, or has a
> relationship to a node that is hosted. I'll leave it to Ran to explain why
> this needs to be the case. :)
>
>
>
> On Wed, Sep 6, 2017 at 6:27 AM, Ran Ziv  wrote:
>
> > (I'll let Tal take this one :P)
> >
> > On Wed, Sep 6, 2017 at 2:26 PM, D Jayachandran <
> > d.jayachand...@ericsson.com>
> > wrote:
> >
> > > Yes, I can see that Ran. So that was my question , why was role
> > > being added to the types ?
> > > TOSCA spec does not say about a parameter called role. I feel this
> > > is not aligned with TOSCA spec.
> > >
> > > Regards,
> > > DJ
> > >
> > > -Original Message-
> > > From: Ran Ziv [mailto:r...@cloudify.co]
> > > Sent: Wednesday, September 06, 2017 2:16 PM
> > > To: dev@ariatosca.incubator.apache.org
> > > Subject: Re: Use & impact of role/host attribute in ARIA
> > >
> > > This is where the execution plugin decides whether to run locally or
> > > remotely (ssh):
> > > https://github.com/apache/incubator-ariatosca/blob/0.1.
> > > 1/aria/orchestrator/execution_plugin/instantiation.py#L42
> > >
> > > This is indeed related to the "host" role definition.
> > >
> > > Here you can see the assignment of the "host" role to the Compute type:
> > > https://github.com/apache/incubator-ariatosca/blob/
> > > 1e883c57abb733b10e13f0b7005cf564886d3fb1/extensions/aria_
> > > extension_tosca/profiles/tosca-simple-1.0/nodes.yaml#L63
> > >
> > >
> > > Ran
> > >
> > > On Wed, Sep 6, 2017 at 10:07 AM, D Jayachandran <
> > > d.jayachand...@ericsson.com
> > > > wrote:
> > >
> > > > Hi,
> > > >
> > > > I just noticed the "role" attribute is added for different
> "capability"
> > > > and "node" types in ARIA profiles. There is no such role with the
> > > > TOSCA spec.
> > > > Why is this been added in the profiles ? What is the use of them ?
> > > >
> > > > I faced an issue when I run a local script as part of the
> > > > Interface operation. The script was provided to the execution
> > > > plugin as "run_script_with_ssh" rather than "run_script_locally".
> > > > The "role" seemed to have a saying on deciding this. Based on this
> > > > role a host is being added to any node instance. With the host
> > > > being set a script is configured either as " run_script_with_ssh"
> > > > rather than "run_script_locally".
> > > >
> > > > So I want to understand under which cicumstances is a host being
> > > > added to a node and which decided if the script execution is local
> or ssh ?
> > > >
> > > >
> > > > Regards,
> > > > DJ
> > > >
> > >
> >
>

RE: Use & impact of role/host attribute in ARIA

2017-09-07 Thread D Jayachandran 
Hi Tal,

How do we conclude certain normative types play "special roles" ? I will wait 
for Ran to explain on the remove execution part.


Regards,
DJ

-Original Message-
From: Tal Liron [mailto:t...@cloudify.co] 
Sent: Wednesday, September 06, 2017 7:05 PM
To: dev@ariatosca.incubator.apache.org
Subject: Re: Use & impact of role/host attribute in ARIA

First of all, "role" is an extension and is only used internally. It is indeed 
not defined by TOSCA and you shouldn't be using it yourself.

The reason "role" exists is to avoid hardcoding functionality to type names. 
Certain normative types play special roles in TOSCA: certain relationships are 
special, as are certain capabilities, data types, etc. In order to avoid having 
ARIA look for a specific type name, it checks the "role" extension. Internally, 
"role" is inherited (and can be overridden), so that anything that inherits 
from tosca.nodes.Compute, for example, would also have the "host" role. (For 
past versions of the NFV Profile, we likely had the VDU type as having "host" 
role, even though it did not inherit from tosca.nodes.Compute).

Then execution plug tries to find out if the operation is hosted remotely by 
seeing if the node is hosted: either a host itself, or has a relationship to a 
node that is hosted. I'll leave it to Ran to explain why this needs to be the 
case. :)



On Wed, Sep 6, 2017 at 6:27 AM, Ran Ziv  wrote:

> (I'll let Tal take this one :P)
>
> On Wed, Sep 6, 2017 at 2:26 PM, D Jayachandran < 
> d.jayachand...@ericsson.com>
> wrote:
>
> > Yes, I can see that Ran. So that was my question , why was role 
> > being added to the types ?
> > TOSCA spec does not say about a parameter called role. I feel this 
> > is not aligned with TOSCA spec.
> >
> > Regards,
> > DJ
> >
> > -Original Message-
> > From: Ran Ziv [mailto:r...@cloudify.co]
> > Sent: Wednesday, September 06, 2017 2:16 PM
> > To: dev@ariatosca.incubator.apache.org
> > Subject: Re: Use & impact of role/host attribute in ARIA
> >
> > This is where the execution plugin decides whether to run locally or 
> > remotely (ssh):
> > https://github.com/apache/incubator-ariatosca/blob/0.1.
> > 1/aria/orchestrator/execution_plugin/instantiation.py#L42
> >
> > This is indeed related to the "host" role definition.
> >
> > Here you can see the assignment of the "host" role to the Compute type:
> > https://github.com/apache/incubator-ariatosca/blob/
> > 1e883c57abb733b10e13f0b7005cf564886d3fb1/extensions/aria_
> > extension_tosca/profiles/tosca-simple-1.0/nodes.yaml#L63
> >
> >
> > Ran
> >
> > On Wed, Sep 6, 2017 at 10:07 AM, D Jayachandran < 
> > d.jayachand...@ericsson.com
> > > wrote:
> >
> > > Hi,
> > >
> > > I just noticed the "role" attribute is added for different "capability"
> > > and "node" types in ARIA profiles. There is no such role with the 
> > > TOSCA spec.
> > > Why is this been added in the profiles ? What is the use of them ?
> > >
> > > I faced an issue when I run a local script as part of the 
> > > Interface operation. The script was provided to the execution 
> > > plugin as "run_script_with_ssh" rather than "run_script_locally".
> > > The "role" seemed to have a saying on deciding this. Based on this 
> > > role a host is being added to any node instance. With the host 
> > > being set a script is configured either as " run_script_with_ssh" 
> > > rather than "run_script_locally".
> > >
> > > So I want to understand under which cicumstances is a host being 
> > > added to a node and which decided if the script execution is local or ssh 
> > > ?
> > >
> > >
> > > Regards,
> > > DJ
> > >
> >
>