Modernizing your application

Overview

Are you considering modernizing your application, i.e. migrating it from an on-premises system to a cloud hosted system? If so, CAST Imaging can provide advice and recommendations about what you may need to change in your application before you start the migration process.

How does it work?

A series of checks are run against the application during the generation of results at the end of the analysis process and the result of these checks is presented in a way which makes it easy to see which objects in your application may need work to ensure a smooth migration to a given cloud provider (for example, removal if they are not supported in a cloud environment):

The results provided should be considered as an initial assessment providing “points of interest” that require further investigation to work out:

the effort required to make the necessary changes
the cost involved
the level of existing adherence to “cloud” norms

What scenarios are supported?

Typically, checks are provided for the following types of technologies where modernization (migration to cloud) is attractive:

Mainframe

Checks available for Amazon Web Services (AWS), Microsoft Azure or Google Cloud Platform (GCP):

Database technologies

Checks are available for the following on-premises to cloud migration paths (via Amazon Web Services (AWS), Microsoft Azure or Google Cloud Platform (GCP)), typically focusing on data type, object type and syntax remediation:

IBM DB2 to MySQL
IBM DB2 to PostgreSQL
Oracle Server to PostgreSQL
Microsoft SQL Server to PostgreSQL
Oracle Server to Oracle Cloud

In addition, more general checks are provided for:

data access modes - i.e. how tables are accessed and processed, which can help when adapting application code to access new “cloud” database instances.
database dependencies and adherences - i.e. their criticality (number of actions in the application code using a given table) and the level of difficulty to migrate them (number of objects in the database depending on a given table).

Are there any prerequisites?

CAST Imaging provides a set of “built-in” checks that will automatically be triggered when a compatible technology is found in your application.

In addition, some checks are also provided in a dedicated extension, which will need to be manually installed, see com.castsoftware.sql.movetocloud .

How do I access the recommendations?

In the application landing page, click Ready to view to access the analysis results:

If your application contains technologies for which checks are available, then the Advisor for modernization section will be displayed:

If you do not see the “Welcome” page with the various sections, it may be disabled. See Landing Page in Viewer preferences.

click the scenario you are interested in, for example if you are considering migrating your Mainframe application to Amazon Web Services, click the Move to AWS button.
you will then be directed into a workflow which allows you to choose various different scenarios:

select the option you would like to investigate in each step of the workflow. Results are shown in the last step where the objects impacted or which are candidates for change are shown.
- In this example, the scenarios chosen are:
- Mainframe modernization using Amazon Web Services (AWS)
- Rehosting/replatforming application on EC2
- Cobol Programs candidate for AWS Lambda function conversion (focusing on servless functions as replacements for Cobol Programs)
- Cobol Programs candidate for Cloud function conversion: Data-independent programs

What are the Quick Wins / Minor Cleanup / Major Cleanup categories?

In each step of the workflow, information is displayed in categories:

These categories define the number of checks that have been “triggered”. Each category defines the level of difficulty to deal with the check, with Major Cleanup requiring the most amount of work.

When a specific check is selected, the display changes to show the number of objects that are actually impacted by the check:

What can I do with the recommendations?

When looking at the detailed recommendations (i.e. the objects that are impacted or are recommended for change) you can use the various CAST Imaging features to help you plan the work you need to do make these changes:

Item	Name	Description
1	View Documentation	Displays an explanation about the check that has been selected, together with a rationale (explanation of why the check is important) and a remediation (explanation of how to update the object in preparation for moving to cloud), e.g.:
2	Post-It	Creates a Post-It: a way to annotate the object. For example you could explain what needs changing. See also Post-Its.
3	Tag	Creates a Tag associated to the object: for example you could tag it with the release number you intend to make this change in. See the example below and also Tags.
4	Export	Exports the content of the object list to `.csv` file.
5	Save	Will tag all objects in the list with the same Tag so that they can be easily identified.
6	Investigate	Displays the objects in a dedicated view with the standard viewer features available.
7	Properties	Select an object in the right hand panel to view its properties:

Example using tags

In our example, we’re examining a migration scenario from IBM DB2 to Microsoft Azure PostgreSQL. We’re focusing specifically on syntax remediation - identifying existing IBM DB2 syntax that won’t function in PostgreSQL. The particular check we’re highlighting is “Ensure DB2 Scalar Function CHAR is not used”. According to the documentation, the IBM DB2 CHAR() function must be replaced with PostgreSQL’s equivalent TO_CHAR() function when migrating code between these database systems.

Once we have drilled down through the workflow, we can see a list of all objects where CHAR() is used and the number of times it is used in each object:

To ensure the team dealing with this migration can easily find these objects in the future, it is possible to tag them all. First select them and click the Tags button:

Then add an appropriate tag: in this example we have tagged them with the name of the check “Ensure DB2 Scalar Function CHAR is not used”:

Finally, team members can use the global search feature, searching by tag to display all the objects that need updating:

Upgrading the checks

The checks that are used to provide recommendations are (for the most part, excluding those provided by com.castsoftware.sql.movetocloud ) embedded in the current release of CAST Imaging, therefore if you have updated CAST Imaging to a new release, but have not re-analyzed the application, or the application has been imported into CAST Imaging (from another instance) then you may not have the most recent checks available. See Upgrading the Advisor for more information (Administrator permissions are required to update the checks).