[Container-tools] Way towards implementing nested Nulecule applications

[Jeroen van Meeuwen]

On 2015-11-18 20:03, Ratnadeep Debnath wrote:
> Hi all,
> 
> Those who have been adventurous with the Nulecule spec and have tried
> to implement nested Nulecule applications, 3 or more levels deep, must
> have realized the pain points of doing so:
> 
> - it's hard to use external Nulecule applications out of the box
> 

There are limitations sometimes, but I've not found 
mariadb-centos7-atomicapp or mongodb-centos7-atomicapp that difficult to 
use.

Could you elaborate on what you find it is that is difficult?

> - namespace conflicts in a flat **answers** data
> 

I'm running in to this particular issue myself as well, also later on -- 
when the second "mariadb" Pod gets created like I described on this list 
earlier [1].

I work around both problems by creating Nulecule application container 
images for each of the separate instances, FROM 
projectatomic/mariadb-centos7-atomicapp, and substituting values in 
/application-entity/{Nulecule,artifacts/kubernetes/*.yaml} like so [2].

> - duplicate params across sections in answers data
> 

Amen.

> I have started articulating the ideas(problems and solutions) we have
> been brainstorming on for some time at [1], to improve the developer
> experience when developing nested Nulecule applications.
> 
> [1]: https://github.com/projectatomic/nulecule/issues/187
> 

[1] 
https://www.redhat.com/archives/container-tools/2015-November/msg00208.html
[2] 
https://github.com/kanarip/kolab-atomicapp/blob/master/04-webadmin-database/Dockerfile

-- 
Regards,

-- Jeroen