Using CA AppLogic › Appliance Developer Guide › Appliance Overview › Configure Appliance › Separate Configuration and Data from Code

Separate Configuration and Data from Code

You should separate your configuration and data from the code by placing your data in a separate placeholder volume. In addition, you should separate your code from the os on a read only instantiable volume.

Placeholder volumes are intended for persistent storage as well as provide fixed contents, such as html files for a web server. In addition, placeholder volumes are places where volumes can be attached. Those volumes are used for appliance specific content, such as files and databases that belong to the application, rather than to the appliance class.

Instantiable volumes, unlike placeholder volumes, belong to the appliance class and are copied and migrated with the catalog class.

Important The instantiable volume can be lost between launches of the appliance and will not be preserved when copying and migrating the application where the appliance resides. The only exception is the singleton where instantiable volumes are always preserved.

Follow these steps:

1. Right click the appliance, select Modify Boundary and Volumes.

   The Volumes tab displays.

2. To add the new volume, click Add.

   The Create Volumes dialog displays

3. Enter the following fields:

   Type

   Type of volume. For example: Placeholder

   Name

   Unique name of the volume. For example: data

   Size

   Size of the volume in megabytes or gigabytes. For example: 100M

   Filesystem

   Filesystem that the volume is formatted with. For example: ext3

   Click Next and then Close.

   The Volumes tab displays.

4. Select the volume, enter the volume mount point, such as, /content, in the Mount On column and click OK.

   The Infrastructure Editor displays.

5. Click the Grid Shell icon.
6. To start the volume manage, execute the following command:

   vol manage appliancename.volumename --rw
   

7. To create the content directory, execute the following command:

   mkdir content 
   

8. Place your configuration and data in the separate volume.
9. Separate your code from the os on a read only instantiable volume.
10. Exit the grid shell.

    The Infrastructure Editor displays.

11. Save the application.