Introduction
With OEM installed, the next step is registering the servers and databases you actually want to monitor. This article follows on from our OEM 13.5 Installation on Linux post and walks through adding a target host to OEM, then registering the database and listener running on it, step by step.
Prerequisites
Below are the minimum requirements for a Linux environment:
- Connectivity between the OEM and target servers.
- The target hostname/IP entry added to OEM's
/etc/hostsfile, and vice versa. - Minimum 5GB free disk space on the target machine.
- Root user or sudo access on the target machine.
- Firewall disabled, or ports such as 1521 and 3872 opened between OEM and the target.
Environment Used in This Guide
| Hostname | oem.oraeasy.com |
|---|---|
| OS | OL 7.3 |
| OEM Version | 13c Release 5 (13.5) |
| OMS Home | /oem/app/oracle/middleware |
| Agent Base | /oem/app/oracle/agent |
| Hostname | uat.oraeasy.com |
|---|---|
| OS | OL 8.5 |
| Database Name | ORCLDB |
| Database Version | 19c (19.27) |
| Oracle Home | /u01/app/oracle/product/19c/db_home |
Approach: We'll first add the target host itself to OEM, then add the database and listener running on that host as separate targets.
Step 1: Verify Database Services and Prepare the Target
Confirm the database and listener are already running on the target before OEM tries to discover them, and create the directories the management agent will need once it's deployed.
SQL> select name,open_mode,database_role,log_mode from v$database;
NAME OPEN_MODE DATABASE_ROLE LOG_MODE
--------- -------------------- ---------------- ------------
ORCLDB READ WRITE PRIMARY ARCHIVELOG
SQL> show pdbs
CON_ID CON_NAME OPEN MODE RESTRICTED
---------- ------------------------------ ---------- ----------
2 PDB$SEED READ ONLY NO
3 ORCLPDB READ WRITE NO
[oracle@uat ~]$ lsnrctl status
LSNRCTL for Linux: Version 19.0.0.0.0 - Production on 06-SEP-2025 20:15:42
Copyright (c) 1991, 2025, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=uat.oraeasy.com)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 19.0.0.0.0 - Production
Start Date 06-SEP-2025 20:15:04
Uptime 0 days 1 hr. 10 min. 40 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u01/app/oracle/product/19c/dbhome_1/network/admin/listener.ora
Listener Log File /u01/app/oracle/diag/tnslsnr/uat/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=uat.oraeasy.com)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
Services Summary...
Service "3d7f7aee5db8a4eee0650a00273ebb20" has 1 instance(s).
Instance "orcldb", status READY, has 1 handler(s) for this service...
Service "86b637b62fdf7a65e053f706e80a27ca" has 1 instance(s).
Instance "orcldb", status READY, has 1 handler(s) for this service...
Service "orcldb" has 1 instance(s).
Instance "orcldb", status READY, has 1 handler(s) for this service...
Service "orcldbXDB" has 1 instance(s).
Instance "orcldb", status READY, has 1 handler(s) for this service...
Service "orclpdb" has 1 instance(s).
Instance "orcldb", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@uat ~]$
[oracle@uat ~]$ mkdir -p /u01/app/oracle/agent
[oracle@uat ~]$ mkdir -p /u01/app/oracle/agent_inst
Step 2: Add the Host Target in OEM
Adding the host deploys the OEM management agent onto the target server, which is what actually collects and reports data back to OMS.
Click Setup, then Add Target, then Add Targets.
Under Add Host Target, click Install Agent on Host.
Click Add, then provide the target hostname and platform, then click Next.
Provide the base and instance directories. Click the + sign next to Credential and add credential details for both the oracle and root users, as shown below.
Credential entry for the oracle user:
Credential entry for the root user:
Click Next.
Review the details, then click Deploy Agent.
Monitor the deployment progress.
The agent has been successfully deployed.
Step 3: Add the Database and Listener as Targets
With the agent running, OEM can now discover and register the Oracle targets on that host.
Click Setup, then Add Target, then Add Targets, then click Add Using Guided Process.
In Guided Discovery, type and select Database, Listener, and so on, then click Add.
Click the search icon to add the host.
Click the hostname, then click Select.
Click Next.
Target discovery runs in the background.
Check the box for the discovered database, provide the credentials for the DBSNMP user, then click Test Connection.
If DBSNMP is locked or the password is unknown, reset it on the target database first.
SQL> select username,account_status from dba_users where username='DBSNMP';
USERNAME ACCOUNT_STATUS
-------------------- ----------------
DBSNMP LOCKED
SQL>
SQL> alter user DBSNMP identified by YourPassword account unlock;
User altered.
SQL> select username,account_status from dba_users where username='DBSNMP';
USERNAME ACCOUNT_STATUS
-------------------- -----------------
DBSNMP OPEN
SQL> show pdbs
CON_ID CON_NAME OPEN MODE RESTRICTED
---------- ------------ - ---------- ----------
2 PDB$SEED READ ONLY NO
3 ORCLPDB READ WRITE NO
SQL> alter session set container=ORCLPDB;
Session altered.
SQL> select username,account_status from dba_users where username='DBSNMP';
USERNAME ACCOUNT_STATUS
-------------------- -----------------
DBSNMP OPEN
The connection test succeeds once DBSNMP is unlocked with the correct password.
Select the listener as well, then click Next.
Review the details, then click Save.
Target saving is in progress.
The targets have been saved successfully. Click Close.
Step 4: View the Added Targets
Both the host and its database can now be browsed directly from the Targets menu.
Click Targets, then Host, then click the host you want to view.
From here you can view host-level details like CPU and memory usage.
Similarly, click Targets, then Database, then click the database you want to view.
Here you can view details like active sessions on the target database.
With that, the target host and its database and listener are fully registered and visible in OEM. We'll be covering more OEM activities in future articles, so stay connected.
Thank you for reading!
I hope this content has been helpful to you. Your feedback and suggestions are always welcome. Feel free to leave a comment or reach out with any queries.
Abhishek Shrivastava
Oracle DBA with hands-on experience managing production Data Guard, RAC, GoldenGate, and APEX environments. I write practical, tested installation and troubleshooting guides based on real deployment work.
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