local persistent storage docs fix

[akostadinov]

Hi, this is a copy of openshift/origin#19212

Basically there is a missing step for creating storage classes in the docs. After one goes through the steps in the document, local storage is sitll not working as expected until the necessary storage classes are created. The necessary storage classes are kindly provided by @toni-moreno and @sbengo in openshift/origin#19212 (comment)

What needs fixing?

Add a section for creating the necessary storage classes.

[vikram-redhat]

@tmorriso-rh - PTAL.

@jhou1 @liangxia Please provide the QE review for this PR.

[jhou1]

@qinpingli PTAL.

[qinpingli]

The issue is when the openshift users tried to use local volume, they can not select storageclass for local volume, right?

Yes, now we have this issue.

1. When local storage provisioner creates local PV, it will tag PVs with storageclass name defined in configmap(e.g. this PV is a hdd storage or ssd storage).
2. Openshift users can request storage they needed by storageclassname.
3. But the storageclass name defined in configmap can not be find by "oc get sc|storageclassname" command.
4. So, the web UI can not get storageclass name when creating PVC. The storageclass must be created manually.

[liangxia]

But the storageclass name defined in configmap can not be find by "oc get sc|storageclassname" command.

This sounds like a bug.

[jsafrane]

That's not a bug, it's intention. You can set pv.spec.storageClassName without creating a StorageClass object for it. Either you don't need a StorageClass (they're required for dynamic provisioning, otherwise they're optional) or you'll create one later.

I admit it's confusing to users and we should update our docs with creation of StorageClasses.

[akostadinov]

Also original bug describes a SELinux labeling issue. Any chcon needs to be documented unless this is no longer needed with 3.9+.

[qinpingli]

@akostadinov this was fixed in OCP 3.9 doc.
https://docs.openshift.com/container-platform/3.9/install_config/configuring_local.html

@qinpingli @jsafrane Does this require an update to the docs, or can I close the PR? Thanks.

Cc: @vikram-redhat

[qinpingli]

I think it still needs an update in the doc for storageclasses creation.

[vikram-redhat]

@tmorriso-rh - was a PR created to fix?