Deregistration of an instance from LDAP also removes all the node, or alias, objects and the database objects referring to the instance.
Deregistration of the DB2 server on either a local or a remote machine requires the LDAP node name be specified for the server:
db2 deregister db2 server in ldap
node <node_name>
When the DB2 server is deregistered, any LDAP node entry and LDAP database entries referring to the same instance of the DB2 server is also uncataloged.