Yes, a new thing though it might serve some of the same purposes. The idea is 
to only use engine instance information from the metadata store so the template 
commands will work from anywhere and mostly in any order. On a cluster machine 
if the engine instance data is in the metastore and the binary exists wherever 
it was on the machine registered, then `pio deploy <new-kind-of-instance-id>` 
would work without any other part of the workflow. Also `pio train 
<new-kind-of-instance-id>` would work from any cluster machine with no need of 
special folder layout or manifest.json

Sorry to overload the term but though this new type of engine instance would 
have much of the same info, it would also have to contain the path to the 
binary and maybe other things.

On Sep 16, 2016, at 7:51 PM, Kenneth Chan <> wrote:

Pat, would you explain more about the 'instanceId' as in
`pio register --variant path/to/some-engine.json --instanceId 
some-REST-compatible-resource-id`  ?

Currently PIO also has a concept of engineInstanceId, which is output of train. 
I think you are referring to different thing, right?


On Fri, Sep 16, 2016 at 12:58 PM, Pat Ferrel < 
<>> wrote:
This is a great discussion topic and a great idea.

However the cons must also be addressed, we will need to do this before 
multi-tenant deploys can happen and the benefits are just as large as removing 
`pio build`

It would be great to get rid of manifest.json and put all metadata in the store 
with an externally visible id so all parts of the workflow on all machines will 
get the right metadata and any template specific commands will run from 
anywhere on any cluster machine and in any order. All we need is a global 
engine-instance id. This will make engine-instances behave more like datasets, 
which are given permanent ids with `pio app new …` This might be a new form of 
`pio register` and it implies a new optional param to pio template specific 
commands (the instance id) but removes a lot of misunderstandings people have 
and easy mistakes in workflow.

So workflow would be:
1) build with SBT/mvn
2) register any time engine.json changes so make the json file an optional 
param to `pio register --variant path/to/some-engine.json --instanceId 
some-REST-compatible-resource-id` the instance could also be auto-generated and 
output or optionally in the engine.json. `pio engine list` lists registered 
instances with instanceId. The path to the binary would be put in the 
instanceId and would be expected to be the same on all cluster machines that 
need it.
3) `pio train --instanceId` optional if it’s in engine.json
4) `pio deploy --instanceId` optional if it’s in engine.json
5) with easily recognized exceptions all the above can happen in any order on 
any cluster machine and from any directory.

This takes one big step to multi-tenancy since the instance data has an 
externally visible id—call it a REST resource id…

I bring this up not to confuse the issue but because if we change the workflow 
commands we should avoid doing it often because of the disruption it brings.

On Sep 16, 2016, at 10:42 AM, Donald Szeto < 
<>> wrote:

Hi all,

I want to start the discussion of removing engine registration. How many people 
actually take advantage of being able to run pio commands everywhere outside of 
an engine template directory? This will be a nontrivial change on the 
operational side so I want to gauge the potential impact to existing users.

- Stateless build. This would work well with many PaaS.
- Eliminate the "pio build" command once and for all.
- Ability to use your own build system, i.e. Maven, Ant, Gradle, etc.
- Potentially better experience with IDE since engine templates no longer 
depends on an SBT plugin.

- Inability to run pio engine training and deployment commands outside of 
engine template directory.
- No automatic version matching of PIO binary distribution and artifacts 
version used in the engine template.
- A less unified user experience: from pio-build-train-deploy to build, then 


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