This is what I did when the listener.ora was missing on one of my EBS servers:
1. Login as the oracle software owner on your server
2. Remove softlink in $TNS_ADMIN called "listener.ora" which points to $TNS_ADMIN/mydb_myserver/listener.ora
cd $TNS_ADMIN rm listener.ora3. Create new listener.ora directly under $TNS_ADMIN
cd $TNS_ADMIN vi listener.ora -- add the following -- cdb = (DESCRIPTION_LIST = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = minserver.skead.no)(PORT = 1521)) ) ) SID_LIST_cdb = (SID_LIST = (SID_DESC = (ORACLE_HOME= /orasw/oracle/product/19_21) (SID_NAME = cdb) ) ) USE_SID_AS_SERVICE_cdb = ON STARTUP_WAIT_TIME_cdb = 0 CONNECT_TIMEOUT_cdb = 10 TRACE_LEVEL_cdb = ADMIN LOG_DIRECTORY_cdb = /orasw/oracle/product/19_21/network/admin LOG_FILE_cdb = cdb TRACE_DIRECTORY_cdb = /orasw/oracle/product/19_21/network/admin TRACE_FILE_cdb = cdb ADMIN_RESTRICTIONS_cdb = ON SUBSCRIBE_FOR_NODE_DOWN_EVENT_cdb = OFF # added parameters for bug# 9286476 LOG_STATUS_cdb = ON INBOUND_CONNECT_TIMEOUT_cdb = 60 # ADR is only applicable for 11gDB DIAG_ADR_ENABLED_cdb = ON ADR_BASE_cdb = /orasw/oracle/product/19_21/admin/mydb_myserver #IFILE=/orasw/oracle/product/19_21/network/admin/mydb_myserver/listener_ifile.ora4. Run autoconfig
cd $ORACLE_HOME/appsutil/scripts/mydb_myserver/ ./adautocfg.sh Enter the APPS user password: Result: autoconfig succeeds.5. Create a new softlink under $TNS_ADMIN
cd $TNS_ADMIN ln -s mindb_minserver/listener.ora listener.ora