Installing the OEM Agents on Remote Servers

Installing the Management Agent (OMA) on Remote Servers in Oracle 19c.
In Oracle 19c, the deprecated Oracle Intelligent Agent has been replaced by the Management Agent (OMA), a core component of Oracle Enterprise Manager (OEM) Cloud Control. OMA enables comprehensive monitoring and management of Oracle environments.

The Oracle Management Agent in Oracle 19c is a software component of Oracle Enterprise Manager (OEM) that facilitates monitoring, management, and administration of Oracle databases, applications, and systems. It acts as a local agent deployed on a host to collect and relay data to the Oracle Management Service (OMS) for centralized management. Its key roles include:

• Monitoring and Metrics Collection: Gathers performance metrics, configuration data, and health status of managed targets (e.g., databases, hosts, middleware) in real-time.
• Event and Alert Management: Detects issues based on predefined thresholds, generates alerts, and notifies administrators of critical events.
• Job Execution: Executes automated tasks, such as backups, patching, or scripts, scheduled through OEM.
• Configuration Management: Tracks configuration changes and ensures compliance with standards by collecting and reporting configuration data.
• Data Relay to OMS: Securely communicates collected data to the OMS for centralized storage, analysis, and visualization in the OEM console.
• Plug-in Support: Extends functionality through plug-ins to manage diverse Oracle and non-Oracle technologies.

The agent runs as a lightweight process on the host, communicates over HTTPS, and supports high availability and scalability in enterprise environments. It is essential for proactive monitoring and streamlined administration in Oracle 19c deployments.

In the context of Oracle 19c, the acronym OMA is commonly used informally to refer to the "Oracle Management Agent", even though Oracle's official documentation typically just calls it "Management Agent."
🔍 Clarifying the Terminology

OMA	Stands for Oracle Management Agent — commonly used in community discussions, training materials, and some vendor documentation.
Management Agent	The official term used by Oracle in Enterprise Manager documentation (e.g., "Deploying Management Agents").
OEM Agent	Sometimes used interchangeably with "Management Agent", refers to its role in Oracle Enterprise Manager (OEM).

📘 Example in Oracle Docs (13c / 19c context):
- Oracle uses the phrase: The "Management Agent" is responsible for collecting and uploading information from monitored targets to the Oracle Management Service (OMS).”
🧠 Conclusion: ✅ While OMA is not an official Oracle acronym, it is widely accepted in the Oracle DBA community as shorthand for Oracle Management Agent — particularly in environments running Oracle 12c, 18c, 19c, and newer.

To manage remote databases and clustered environments, the Oracle Management Agent must be installed on each remote server.
Installation Steps:

1. Use the Oracle Enterprise Manager Cloud Control Agent Deployment Wizard or deploy the OMA using silent installation with response files.
2. The OMA binaries are part of the Cloud Control installation and must be deployed to each node.
3. Configuration includes setting up the agent.properties file, ensuring secure communication with the Oracle Management Service (OMS), and verifying correct hostname/IP in the agent configuration.

RAC Configuration Example
Assume a two-node RAC cluster:

1. Nodes: RAC1 and RAC2
2. db_name=V920
3. service_name=V920.acme.com

Ensure that /var/opt/oracle/oratab exists on each node with a database-level entry:

V920:/u01/app/oracle/product/19.0.0:N

Validate cluster node configuration with:

$ olsnodes -n

Update listener.ora on each node to use port 1545, and configure local_listener in the init.ora or SPFILE:

local_listener = '(ADDRESS=(PROTOCOL=TCP)(HOST=RAC1)(PORT=1545))'

On RAC2, update to:

local_listener = '(ADDRESS=(PROTOCOL=TCP)(HOST=RAC2)(PORT=1545))'

TNS Configuration
Configure tnsnames.ora identically on all nodes, adjusting address order for load balancing. Example:

V920.ACME.COM =
  (DESCRIPTION=
    (LOAD_BALANCE=ON)
    (FAILOVER=ON)
    (ADDRESS_LIST=
      (ADDRESS=(PROTOCOL=TCP)(HOST=RAC1.ACME.COM)(PORT=1545))
      (ADDRESS=(PROTOCOL=TCP)(HOST=RAC2.ACME.COM)(PORT=1545)))
    (CONNECT_DATA=(SERVICE_NAME=V920.ACME.COM)))

Once the agent is deployed and running (agentctl start or emctl start agent), Cloud Control automatically detects and discovers targets such as databases and RAC instances.
You can verify successful discovery by checking the OEM console:

- Databases folder > V920.acme.com
  - Subfolder: Cluster Database Instances
    - Instances: V9201.acme.com, V9202.acme.com

In clustered environments with shared ORACLE_HOME:

• Each RAC node should have a separate OMA installation to avoid conflicts with .q state files.
• Alternatively, use symbolic links or CDSL to isolate agent-specific files.
• Set ORA_OEMAGENT_DIR to redirect state files:
  

  export ORA_OEMAGENT_DIR=/usr/oracle/agent
  emctl start agent
  

SNMP Configuration (Advanced/Optional)
Though not commonly used with OMA, if SNMP monitoring is needed:

• Update CONFIG.master, CONFIG.encap, and start_peer scripts for SNMP trap forwarding.
• Adjust ports and community strings accordingly.

Summary The Oracle Management Agent (OMA) in Oracle 19c is the modern replacement for the Oracle Intelligent Agent. It provides secure, scalable, and automated monitoring for Oracle systems and integrates tightly with Oracle Enterprise Manager Cloud Control. Deployment in RAC environments requires special considerations for shared homes and agent isolation.

Before moving on to the next lesson, click the Quiz link below to test your mastery of OEM concepts.
Installing OEM - Quiz