Topology and Orchestration Specification for Cloud Applications (TOSCA) and Juju

[Johannes Wettinger]

On Fri, Aug 24, 2012 at 9:11 PM, Gustavo Niemeyer
<gustavo.niemeyer at canonical.com> wrote:
>> By offering this option, the creator of a particular charm can decide
>> either to put all the conditional logic into one single hook
>> implementation or to deliver a number of implementations for different
>> platforms. Depending on the particular use case, either the one or the
>> other approach might be more appropriate. What do you think?
>
> Have you ever considered what's the root of your perception that juju
> looks simpler?

I did. :-) I mean the manifest.yaml inside a charm looks really
simple. But if a charm is designed to be portable, i.e. runnable on
many platforms, then the implementation of the hooks gets quite
complex including sophisticated conditional logic. In TOSCA there's
more complexity already inside the template ("manifest"), but as a
result the implementation artifacts ("hook implementations") can be
simpler.

At the end of the day, the complexity has to be somewhere and cannot
be avoided if portability is a goal. The only question is where to put
it. I definitely like Juju's approach to keep things simple,
especially the core of a charm, namely its manifest. But imho it
wouldn't hurt the simplicity of Juju, if some of the complexity can
*optionally* be transferred to the manifest.yaml. This would be an
option and wouldn't bring much additional complexity to the manifest
file.

Johannes