You can use the Admin Console add cluster support to a developer domain.
Log on to the Admin Console. For instructions, see To Log On to the Admin Console.
From the left pane, click Application Server.
Click the Add Cluster Support button in the General tab.
The Add Cluster Support page appears. Review the information on this page and click OK.
In the Restart Required Page, click the Stop Instance button to stop the domain.
Log in to the machine where the domain is installed and run the following command: as-install/bin/asadmin list-domains. Verify that the domain was stopped.
Run the following command: as-install/bin/asadmin start-domain <domain-name>
The restarted domain supports clustering.
If the restarted domain does not show clustering capabilities, stop the domain, reboot the machine on which the domain is installed, and restart the domain as shown in step 7.