IBM Host Access Transformation Services (HATS) allows you to reuse and transform your user experience, by extending terminal applications to the web, mobile, portal, rich client, or as standard SOAP or RESTful web services without touching the existing application.
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A HATS project is bound to a version of an application server that is selected during project creation itself. In an ideal scenario, the server to be used is identified first. This project can then be deployed on that server after creation.
This project cannot be deployed to another application server, because of some internal configuration that is performed during project creation. But there are scenarios where the project might be needed to run on another application server.

1. Users used server A while exploring HATS but want to use Server B for actual deployment.
2. Migrating to light weight server instead of heavy weight server for development or vice versa.
3. Migration due to cost, performance, and maintenance. 

If users encounter the above scenarios, they can migrate using either of the 2 approaches below:
     -    Recreate the project with the new server. Issue with this approach is that it requires additional effort and time, especially if the project has multiple assets.
     -    Migration can also be done without recreating the projects.

• • This can be achieved by carefully changing internal configuration and folder structure. 
  • Changes that are needed to be done, depend on the application server and will differ from server to server. There are chances of the project getting corrupted if required files or configurations are deleted or modified.

This blog recommends steps on how to migrate from one application server to another, by changing the internal configuration. Following are the 2 application servers which can be used inter-changeably:

• IBM WLP (WebSphere Liberty Profile) – a light weight application server.
• IBM WAS (WebSphere Application Server) – a fully loaded application server.

Following changes are required on the project and the enterprise application project – the EAR file. Please note that these are needed only to run from the HATS studio. For HATS runtime, just deploying the project EAR file on another application server is good enough.

Migration from WAS to WLP:

1. Add WLP server to the workspace – ignore if already added.
2. Switch to navigator view and select created HATS project and select ‘properties’ menu from context menu to open properties window.
3. Select ‘Project Facets’
4. Unselect ‘WebSphere Web (Co-existence)’ and ‘WebSphere Web (Extended)’. Select ‘WebSphere Application Server Liberty’ in Runtimes tab. 
5. Select Enterprise application project created for HATS project and select ‘properties’ menu from context menu to open properties window.
6. Select ‘Project Facets’.
7. Unselect ‘WebSphere Web (Co-existence)’ and ‘WebSphere Web (Extended)’. Select ‘WebSphere Application Server Liberty’ in Runtimes tab.
8. Save changes and redeploy the project. 

Migration from WLP to WAS:

1. Add WAS server to the workspace – ignore if already added.
2. Switch to navigator view and select created HATS project and select ‘properties’ menu from context menu to open properties window.
3. Select ‘Project Facets’.
4. Select ‘WebSphere Application Server Traditional Vx.y’ in Runtimes tab and select ‘WebSphere Web (Co-existence)’ and ‘WebSphere Web (Extended)’.
5. Select Enterprise application project created for HATS project and select ‘properties’ menu from context menu to open properties window.
6. Select ‘Project Facets’.
7. Select ‘WebSphere Application Server Traditional Vx.y’ in Runtimes tab and select ‘WebSphere Web (Co-existence)’ and ‘WebSphere Web (Extended)’.
8. Save changes and redeploy the project.

Contact:

For further information on Automation, Services offerings or Technical details in IBM HACP/HATS please connect with HCL mainframe Lab services.

Shivaprasad N
Technical Specialist

Mainframe Lab services