Add support for OpenShift 4.0

[cben]

ManageIQ uses /oapi/Foo endpoints for all openshift-specific resources.
This was an openshift-specific path, probably predating api groups in k8s; all these have long been mirrored as various "normal" api groups e.g. /apis/template.openshift.io/Template.

IIUC, openshift/origin#21782 completely dropped /oapi from Openshift 4.0.
Good riddance, but that means ManageIQ will not work against Openshift 4.0.

cc @oourfali @jhernand @agrare for visibility.

[cben]

Not sure yet how much "will not work". Ideally k8s parts should still work, but I don't remember how tolerant the inventory code is to partial failures. Will update when I get around to testing this.

[agrare]

Hey @cben thanks a lot for the ping!

It it as simple as switching from /oapi to /apis/user.openshift.io? Is that newer api available on older openshift versions as well, or is it a hard if >= 4.0; /apis/user.openshift.io; else /oapi; end

[cben]

@ourfali tells me we don't intend to support openshift 4.x at all.

It it as simple as switching from /oapi to /apis/user.openshift.io?

A little bit harder, as there are multiple api groups under /apis, and we'll need a separate Kubeclient::Client for each group.

Is that newer api available on older openshift versions as well

Yes, starting 3.6. Do we support anything older?

if >= 4.0

Due to openshift/origin#22901, version-sniffing 4.x is problematic.
But presence of old / new endpoints is not hard to test.

[cben]

@agrare Does https://github.com/ManageIQ/manageiq-providers-openshift/blob/master/app/models/manageiq/providers/openshift/container_manager/container_template.rb also need adaptation?
It already does api_group => "template.openshift.io" to process the template itself, but not sure about create_object... I think it takes apiVersion and kind from the template itself, so maybe it does work? (assuming the template is openshift 4 compatible)

Also create_project

manageiq-providers-openshift/app/models/manageiq/providers/openshift/container_manager.rb

Lines 39 to 40 in 29370d2

	def create_project(project)
	connect.create_project_request(project)

I no longer remember what user-visible functionalities these supports :-|

It might make sense to lift some of the #164 changes into container_manager_mixin.rb, your call.

---

As you notice, I'm increasingly losing touch with manageiq, had near zero work time for it last few months... The time I do have I prefer to focus on kubeclient.

[agrare]

Thanks @cben I missed create_project (I was searching for \.connect)

I thought that connect_client handled that by doing api, version = api_version.split('/', 2) and :path => '/apis/' + api but I'll double check