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#### Add the PowerShell configuration script

Next, add the configuration script called *configure.ps1* to the *%HOME%_\site* directory with the following code:

If you created a server-level data source, restart the App Service Linux application. Tomcat resets `CATALINA_BASE` to `/home/tomcat` and uses the updated configuration.

# [Windows](#tab/windows)

You can't directly modify a Tomcat installation for server-wide configuration because the installation location is read-only. To make server-level configuration changes to your Windows Tomcat installation, the simplest way is to do the following on app start: 

1. Copy Tomcat to a local directory (`%LOCAL_EXPANDED%`) and use that as `CATALINA_BASE` (see [Tomcat documentation on this variable](https://tomcat.apache.org/tomcat-10.1-doc/introduction.html)).
1. Add your shared data sources to `%LOCAL_EXPANDED%\tomcat\conf\server.xml` using XSL transform.

#### Add a startup file

Create a file named `startup.cmd` `%HOME%\site\wwwroot` directory. This file runs automatically before the Tomcat server starts. The file should have the following content:

This PowerShell completes the following steps:

1. Check whether a custom Tomcat copy exists already. If it does, the startup script can end here.
2. Copy Tomcat locally.
3. Add shared data sources to the custom Tomcat's configuration using XSL transform.
4. Indicate that configuration was successfully completed.

#### Add XSL transform file

A common use case for customizing the built-in Tomcat installation is to modify the `server.xml`, `context.xml`, or `web.xml` Tomcat configuration files. App Service already modifies these files to provide platform features. To continue to use these features, it's important to preserve the content of these files when you make changes to them. To accomplish this, use an [XSL transformation (XSLT)](https://www.w3schools.com/xml/xsl_intro.asp).

Add an XSL transform file called *configure.ps1* to the *%HOME%_\site* directory. You can use the following XSL transform code to add a new connector node to `server.xml`. The *identity transform* at the beginning  preserves the original contents of the configuration file.

Or, you can manually change the setting in the Azure portal:

1. Go to **Settings** > **Configuration** > **Application settings**.
1. Select **New Application Setting**.
1. Use these values to create the setting:
   1. **Name**: `CATALINA_BASE`
   1. **Value**: `"%LOCAL_EXPANDED%\tomcat"`

#### Finalize configuration

Finally, you place the driver JARs in the Tomcat classpath and restart your App Service. Ensure that the JDBC driver files are available to the Tomcat classloader by placing them in the */home/site/lib* directory. In the [Cloud Shell](https://shell.azure.com), run `az webapp deploy --type=lib` for each driver JAR: