Allow to configure workspaces persistent storage from Eclipse Che CR

[ibuziuk]

Is your task related to a problem? Please describe

CheCluster API v2 [1] is going to have the dedicated properties for workspace storage configuration:

devEnvironments:
  storage:
      pvcStrategy: <strategy> // 'per-user' or 'per-workspace'
      perUserStrategyPvcConfig:
        claimSize: <size> // will only be applied for 'per-user'
        storageClass: <classname> // will only be applied for 'per-user'

once specified those properties should be used as defaults for DevWorkspaces creation

[1] eclipse-che/che-operator#1324

Describe the solution you'd like

Configure storage related properties from the Eclipse Che CR

Release Notes Text

Workspaces persistent storage options like the strategy and the size are now configurable using CheCluster CR. It's also possible to set the storage strategy to per-workspace now so that developers will be able to run multiple workspaces concurrently.

[amisevsk]

Related: devfile/devworkspace-operator#843

[amisevsk]

A few additional notes:

• claimSize is configured in the DevWorkspaceOperatorConfig. However, the DWOC has separate configuration based on workspace storage-type (you can set a different default for per-workspace vs common). It's not clear which default the CheCluster config refers to
• storageClass is configured in the DWOC as well.
• pvcStrategy would need to be consumed by whichever component creates DevWorkspaces (e.g. the Dashboard) as DWO does not provide a way to configure the default storage type used for workspaces. Also in terms of naming, pvcStrategy may be somewhat confusing as the DevWorkspace attribute is controller.devfile.io/storage-type

[AObuchow]

claimSize is configured in the DevWorkspaceOperatorConfig. However, the DWOC has separate configuration based on workspace storage-type (you can set a different default for per-workspace vs common). It's not clear which default the CheCluster config refers to

This ambiguity has been confusing me a bit, too. Something that came to mind, however, is perhaps we need to use the pvcStrategy and claimSize in combination to determine which default PVC size should be set on DWO?
E.g. if pvcStrategy is set to per-workspace and claimSize is set to 7Gi then the per-workspace PVC size will be set to 7Gi on the DWOC.

pvcStrategy would need to be consumed by whichever component creates DevWorkspaces (e.g. the Dashboard) as DWO does not provide a way to configure the default storage type used for workspaces. Also in terms of naming, pvcStrategy may be somewhat confusing as the DevWorkspace attribute is controller.devfile.io/storage-type

This question still holds - from what I understand, pvcStrategy should be consumed by the Dashboard to set the storage-type attribute in the workspace.

[ibuziuk]

@amisevsk @AObuchow folks, wdyt about adding default strategy to the DWOC as part of this issue e.g.

  workspace:
    defaultStorageStrategy: 'common| per-workspace | ephemeral'  

This would allow configuring storage from the Che Cluster CR without a need of adding extra attributes on the dashboard level

[amisevsk]

On the DevWorkspace Operator level, we can't change the default. Currently, DWO treats an empty/blank storage type as common -- if it was possible to configure this default then we would risk orphaning workspace data on the cluster whenever it was changed. For example, if the default is changed from common to per-workspace, all existing workspaces would need to be re-provisioned with per-workspace storage, and all storage kept in the common PVC would be untracked.

In fact, the DevWorkspace Operator does not allow changing the storage type of a DevWorkspace once it has been used for this reason. Otherwise, flows like

• Create common storage DevWorkspace, clone a large repository
• Switch storage-type to ephemeral
• Delete the DevWorkspace

would result in all the data saved in the common PVC to be left in-tact with no clear way to clean it up short of doing it manually or deleting the DevWorkspace. Eventually, this would result in the common PVC being full of old data, preventing new workspaces from functioning correctly.