We need an implementation of Nulecule's Storage Requirements

[veillard]

Needed for all those examples around databases etc ...
Spec v2 is at
https://github.com/projectatomic/nulecule/tree/master/spec/0.0.2#storage-requirements-object

[vpavlin]

Looking at https://github.com/projectatomic/nulecule/tree/master/spec#storageRequirementsObject I am not sure how do we translate this to a real storage. Any more detailed explanation on how to implement this feature?

[goern]

storageRequirements correspond to Persistent Storage in Kubernetes two steps need to be performed:

1. the application packager has a storage requirement, this must be translated to a persistant storage claim object to be deployed to kubernetes or openshift3
2. the deployment guy needs to provision storage (within kube or openshift) without this, 0. will lead to a blocked deployment of the application

step 1. is implemented either as a) part of answers.conf or b) a kube config that is dropped in the correct artifacts directory.

I would vote for a) which also means that we need to generate a PersistentVolume object and deploy it during atomic run.

AFAIK there is no need to respect any sequence of deployment.

[kanarip]

OpenShift specifies an attribute "volumeMounts" to a container, which seems very much like what we need.

Edit: Separately, a volume.yaml seems to be used for the claim and the dimensions of the storage.

[goern]

ja, OpenShift (more precisely Kubernetes) has a two fold concept:

1. there is a Persistent Volume Claim, that claim is issued by the application and can be generated out of a Nulecule file by atomicapp's openshift provider
2. that claim must be satisfied by a Persistent Volume, which is configured/provisioned by the platform administrator

Both must match, so a claim for 512Mi will be satisfied by a volume of 512Mi...

Further info: https://github.com/kubernetes/kubernetes/blob/release-1.0/docs/design/persistent-storage.md

[dustymabe]

We just merged persistent storage for kubernetes in #460. Closing.