Databases

Oracle DB 21c Client User Guide

| Product: Oracle DB 21c Client

Overview

This guide covers the deployment and configuration of Oracle Database Client 21c on Linux using cloudimg AMIs from the AWS Marketplace. Oracle Database Client 21c provides the tools and libraries needed to connect to and manage remote Oracle 21c and earlier database instances. It includes SQL*Plus, Oracle Net, and other client utilities without requiring a full database installation.

What's included in this AMI:

  • Oracle Database Client 21c 21.3.0.0 installed at /u01
  • Dedicated oracle OS user with environment script (setEnv.sh)
  • SQL*Plus for connecting to remote Oracle databases
  • OS package update script for keeping the system current
  • AWS CLI v2 for AWS service integration
  • Systems Manager Agent (SSM) for remote management
  • CloudWatch Agent for monitoring
  • Latest security patches applied at build time
  • 24/7 cloudimg support with guaranteed 24 hour response SLA

Prerequisites

Before launching this AMI, ensure you have:

  1. An active AWS account
  2. An active subscription to the Oracle DB 21c Client listing on AWS Marketplace
  3. An EC2 key pair for SSH access
  4. The hostname, port, and service name of the Oracle Database you wish to connect to

Recommended Instance Type: t3.small (2 vCPU, 2 GB RAM) or larger. The minimum requirements are 1 vCPU, 1 GB RAM, and 20 GB disk space.

Step 1: Launch the AMI

  1. Navigate to the AWS Marketplace and search for "Oracle DB 21c Client cloudimg"
  2. Click Continue to Subscribe, accept the terms, then Continue to Configuration
  3. Select your preferred Region and Software Version
  4. Click Continue to Launch
  5. Choose Launch through EC2 for full control over instance configuration
  6. Select your instance type (t3.small recommended)
  7. Configure storage: 20 GB gp3 minimum
  8. Configure your Security Group with the following inbound rules:
Port Protocol Source Purpose
22 TCP Your IP SSH access
  1. Select your EC2 key pair and launch the instance

Step 2: Connect via SSH

Once your instance is running and has passed both status checks (2/2), connect using SSH:

ssh -i your-key.pem ec2-user@<public-ip-address>

To switch to the root user:

sudo su -

Important: Wait for the EC2 instance to reach 2/2 successful status checks before connecting.

Step 3: Switch to the Oracle User and Set Environment

The Oracle Client software is owned by the dedicated oracle OS user. Switch to this user and source the environment. Please type this command rather than copying and pasting:

sudo su - oracle
cd $HOME
. ./setEnv.sh

Step 4: Configure tnsnames.ora

Before connecting to a remote Oracle Database, create a tnsnames.ora configuration file. Replace the placeholder values with your target database details:

cd $HOME
. ./setEnv.sh

echo 'MY_DATABASE =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = YOUR_DB_HOSTNAME)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = YOUR_SERVICE_NAME)
    )
  )
' > "$ORACLE_HOME/network/admin/tnsnames.ora"

Step 5: Connect to a Remote Database via SQL*Plus

cd $HOME
. ./setEnv.sh
sqlplus 'system/password@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=your-db-host)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=your-service-name)))'

Replace system, password, your-db-host, and your-service-name with your actual connection details.

Server Components

Component Version Install Path
Oracle Client 21c 21.3.0.0 /u01

Filesystem Layout

Mount Point Description
/ Root filesystem
/boot Operating system kernel files
/u01 Oracle software installation directory

On Startup

An OS package update script runs on first boot. To disable:

rm -f /stage/scripts/initial_boot_update.sh

crontab -e
# Delete the @reboot line, save and exit

Troubleshooting

Cannot connect via SSH

  1. Verify the instance has reached 2/2 status checks
  2. Confirm your security group allows inbound TCP port 22 from your IP
  3. Ensure you are connecting as ec2-user with the correct key pair

SQL*Plus cannot connect to remote database

  1. Verify the target database is running and accepting connections
  2. Check the hostname, port, and service name are correct
  3. Ensure the target database security group allows port 1521 from this instance
  4. Test connectivity: telnet <db-host> 1521

Security Recommendations

  • Restrict SSH access: Only allow port 22 from trusted IP addresses
  • Secure credentials: Never store database passwords in plain text files
  • Use Oracle Wallet: Configure Oracle Wallet for secure credential storage
  • Encrypt connections: Configure Oracle Net Services to use SSL/TLS encryption

Support

If you encounter any issues with this product, contact cloudimg support:

  • Email: support@cloudimg.co.uk
  • Website: www.cloudimg.co.uk
  • Support hours: 24/7 with guaranteed 24 hour response SLA