Allow empty strings pvc storageClassName

[nervo]

In some situations, it coud be useful to define pvc storageClassName as empty string (not null) to disable dynamic provisioning.

Right now, it's not fully possible in this chart, and the way of doing it may vary depends on the chart/subchart:

PostgreSQL (using the storageClass "-" de facto standard) :

postgresql:
  ...
  persistence:
    ...
    storageClass: "-"

Elasticsearch (using full "volumeClaimTemplate" block) :

elasticsearch:
  ...
  volumeClaimTemplate:
    ...
    storageClassName: ""

Zammad itself:

persistence:
  ...
  storageClass: ""

In this last example, zammad is using half of the de facto standard :)
First, storageClass is used instead of storageClassName (which, in my opinion, is a good thing).
But then, the special value "-" is not handled, and worst, if storageClass is an ampty string, it leads to no storageClassName at all because of the "with" usage right here: https://github.com/zammad/zammad-helm/blob/master/zammad/templates/statefulset.yaml#L298

[monotek]

So you're asking to change the default to "-"?
Why should we change this for everyone if it can be set throught the values.yaml file?

[nervo]

@monotek nope :)

storageClassName must be either:

• an empty string
• a string
• absent/null

Each one of these has a different meaning, empty string for no class at all, string for a specific class, and absent/null for the default class.
With the current implementation, there is no difference between empty string, absent or null because of go template "with" method, which treat all of them the same way.

As a workaround, a standard is to allow user to pass a special string "-" to storageClass, resulting in a true empty string in the final manifest.
You can find an implementation in one of the subchart your are using, bitnami/postgresql: https://github.com/bitnami/charts/blob/master/bitnami/postgresql/templates/statefulset.yaml#L607 and https://github.com/bitnami/charts/blob/master/bitnami/common/templates/_storage.tpl#L15

In all cases, the default should remain juste like it is now, absent/null, aka. the default system class

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[nervo]

I still believe :)

[monotek]

Do mind to provice an pr?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[monotek]

willl be fixed in: #115