Page History

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Going forward, we want to implement a more fine-grain and generic approach.

We For example, in the GUI we would like to have a storage provider field for the CO and DO windows (this equates to the name of one and only one storage provider). If the admin inputs a specific storage provider and does not use the storage tags field, he can enter in an arbitrary number of key/value pairs in another text field (perhaps we would provide a nice entry dialog to make this easier in the GUI). These key value pairs can be passed into the storage driver when it's asked to create (or update) a volume and the storage driver can decide what each and every key/value pair means.We would like to add one method to the PrimaryDataStoreDriver interface:, if anything.

References

JIRA-xxxx: https://issues.apache.org/jira/browse/CLOUDSTACK-xxxx

Use

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cases

• An admin wants to ensure a root or data disk uses the plug-in of a specific storage vendor because he wants to make sure he can leverage vendor-specific properties.
• The admin creates a Compute or Disk Offering and selects the desired storage plug-in from a combo box. The admin enters in an arbitrary collection of key/value pairs (in the following form: key=value;key=value;key=value). These keys and values are vendor specific and have no meaning to CloudStack (CloudStack simply passes them to the selected storage plug-in and the plug-in decides what, if anything, to do for each key/value pair). We will likely have a dialog in the GUI that makes entry of key/value pairs easier and less error prone than manually entering them in.
• A user executes such a Compute or Disk Offering, which leads to the creation of a root or data disk (respectively) that was created using the storage plug-in specified in the Compute or Disk Offering and the arbitrary collection of key/value pairs, if any.

High-Level Flow Chart

New API added to PrimaryDataStoreDriver that can be returned to CloudStack clients

In order to help a GUI UI perform checking on the value of a given key as well as what keys are applicable, we intend to add a method to the PrimaryDataStoreDriver interface with the following interface:

List<StringMap<String, String> getPropertiesAndTypes();

The key of the returned list map is a String representing a given property that is supported by the plug-in. For example, "burstIops". These are vendor specific and have no meaning to CloudStack.

The value of the returned list map is a String representing the type of the property. For example, "Integer", "Float", "String". All supported types will be listed as public static final member variables in the PrimaryDataStoreDriver interface.

Example output:

[ ("burstIops", "String"), ("replicas", "Integer") ]

A new API will be added to CloudStack that returns such a list map for a given storage plug-in. With the above information, the client a UI could display to the admin all applicable properties and perform basic type checking on assigned values based on returned types.

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The GUI will likely provide a helper dialog to list all applicable properties for a given storage plug-in as well as performing basic verification of input based on the type the property is (ex. Integer).

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Database changes

We will need to add two columns to the cloud.disk_offering table: provider and custom_properties.

The provider value should match one of the provider values in the storage_pool table.

The custom_properties value should be of the following format: key_1=value_1;key_2=value_2;key_3=value_3...key_n=value_n

Existing interface changes

In the PrimaryDataStoreDriver interface, we will need to change the following API:

From

public void createAsync(DataStore dataStore, DataObject dataObject, AsyncCompletionCallback<CreateCmdResult> callback)

To

public void createAsync(DataStore dataStore, DataObject dataObject, Map<String, String> customProperties, AsyncCompletionCallback<CreateCmdResult> callback)

Any code in the CloudStack codebase can be changed as part of this process. However, at least one plug-in (from NetApp) does not have its code in the CloudStack codebase, so this is a reminder for me to e-mail them and ask them to make this change.