Databases Azure

Oracle Database 21c Express Edition on Oracle Linux 8 on Azure User Guide

Last updated: 2026-04-13 | Product: Oracle Database 21c Express Edition on Oracle Linux 8 on Azure

Overview

This guide covers the deployment and configuration of Oracle Database 21c Express Edition on Oracle Linux 8 on Microsoft Azure using cloudimg's pre configured virtual machine image from the Azure Marketplace. Oracle Database 21c Express Edition is the free to use edition of Oracle Database, ideal for development, learning, and small production workloads. This variant provides full Oracle Database functionality on the Oracle Linux 8 platform with no licence cost.

What's included in this VM image:

Oracle Database 21c Express Edition 21.3.0.0.0 (64 bit) installed at /opt/oracle
Preconfigured XE container database with XEPDB1 pluggable database ready to start
Oracle Listener preconfigured on port 1521
Dedicated oracle OS user with environment scripts
Helper scripts for starting and stopping the database and listener
Randomly generated SYSTEM user credentials
OS package update script for keeping the system current
Azure Linux Agent (waagent) for Azure integration
Cloud init for automated provisioning
Latest security patches applied at build time
24/7 cloudimg support with guaranteed 24 hour response SLA

Platform: Microsoft Azure (Gen2 Hyper V) Default user: azureuser Database SID: XE Pluggable database: XEPDB1

Prerequisites

Before deploying this image, ensure you have:

An active Microsoft Azure subscription
Access to the Azure Portal or Azure CLI
An SSH key pair for Linux VM access
Familiarity with Azure VM management

Recommended VM Size: Standard_D2s_v3 (2 vCPU, 8 GB RAM) or larger. The minimum requirements are 2 vCPU, 2 GB RAM, and 20 GB disk space, but Oracle Database 21c Express benefits significantly from additional memory for better performance.

Step 1: Deploy the Virtual Machine

Option A: Azure Portal

Navigate to the Azure Marketplace and search for "Oracle Database 21c Express Edition Oracle Linux 8 cloudimg"
Select the image and click Create
Configure the basics:
Subscription: Select your Azure subscription
Resource Group: Create new or select existing
Virtual Machine Name: Enter a name for your VM
Region: Select your preferred Azure region
Size: Standard_D2s_v3 recommended
Under Administrator Account, select SSH public key and enter your key
Under Inbound Port Rules, allow SSH (port 22)
On the Networking tab, add an additional inbound rule for TCP port 1521 from your trusted IP addresses
Click Review + Create, then Create

Option B: Azure CLI

az vm create \
  --resource-group myResourceGroup \
  --name my-oracle-db-21c-xe-vm \
  --image cloudimg:oracle-db-21c-xe-oel8:default:latest \
  --size Standard_D2s_v3 \
  --admin-username azureuser \
  --generate-ssh-keys \
  --public-ip-sku Standard

Open port 1521 for Oracle Listener access from your trusted IP:

az vm open-port \
  --resource-group myResourceGroup \
  --name my-oracle-db-21c-xe-vm \
  --port 1521 \
  --priority 1010

Important: Restrict port 1521 to trusted application servers or your IP only. Do not open the Oracle Listener port to the public internet.

Step 2: Connect via SSH

Once your VM is running, connect using SSH:

ssh azureuser@<public-ip-address>

To find your VM's public IP:

az vm show --resource-group myResourceGroup --name my-oracle-db-21c-xe-vm --show-details --query publicIps -o tsv

Important: Wait for the VM to reach a running state before connecting. Early connection attempts may produce permission denied errors while cloud init completes initial provisioning.

Step 3: Switch to the Oracle User

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

sudo su - oracle

Three scripts are available in the oracle user's home directory:

setEnv.sh sets the Oracle environment variables, enabling utilities such as sqlplus
start_all.sh starts the XE database and its associated Oracle Listener
stop_all.sh stops the XE database and its associated Oracle Listener

Step 4: Start the Oracle Database and Listener

Run the following commands as the oracle user to start the database and listener:

cd $HOME
. ./start_all.sh

Expected output:

LSNRCTL for Linux: Version 21.0.0.0.0 - Production

Starting /opt/oracle/product/21c/dbhomeXE/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 21.0.0.0.0 - Production
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=0.0.0.0)(PORT=1521)))

The command completed successfully

SQL*Plus: Release 21.0.0.0.0 Production

Connected to an idle instance.

SQL> ORACLE instance started.
Database mounted.
Database opened.

Step 5: Connect with SQL*Plus

Set the Oracle environment variables and launch SQL*Plus:

cd $HOME
. ./setEnv.sh
sqlplus / as sysdba

Expected output:

SQL*Plus: Release 21.0.0.0.0 Production

Copyright (c) 1982, 2021, Oracle. All rights reserved.

Connected to:
Oracle Database 21c Express Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0
SQL>

Verify the database instance and pluggable database:

SELECT STATUS FROM V$INSTANCE;
SHOW PDBS;
EXIT;

Expected output:

STATUS
------------
OPEN

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 XEPDB1                         READ WRITE NO

Type EXIT to leave the SQL*Plus session.

Step 6: Connect Remotely with SQL Developer

To connect to the database from an external tool such as SQL Developer, use the following connection settings:

Setting	Value
Database Type	Oracle
Authentication Type	Default
Username	SYSTEM
Password	See credentials file below
Connection Type	Basic
Hostname	Your VM public IP
Port	1521
Service Name	XEPDB1

Note: To retrieve the SYSTEM user password, refer to the randomly generated credentials file at /stage/scripts/oracle-database-credentials.log.

Server Components

Component	Version	Install Path
Oracle Database 21c Express Edition	21.3.0.0.0	/opt/oracle/product/21c/dbhomeXE
Oracle Linux	8	/
Oracle Listener	21.3.0.0.0	/opt/oracle/product/21c/dbhomeXE/network/admin

Note: Component versions may be updated on first boot by the automatic OS package update script.

Filesystem Layout

Mount Point	Size	Description
/	30 GB	Root filesystem
/boot	1 GB	Operating system kernel files
/opt/oracle	20 GB	Oracle software and data files

Key Oracle directories:

Directory	Purpose
/opt/oracle	Oracle base directory
/opt/oracle/product/21c/dbhomeXE	Oracle home directory
/opt/oracle/oradata/XE	Oracle database data files
/opt/oracle/product/21c/dbhomeXE/network/admin	Listener and TNS configuration files
/opt/oracle/diag	Oracle diagnostic and alert log files
/stage/scripts	cloudimg helper scripts and credentials file

Managing the Oracle Database

The Oracle Database is managed using shell scripts provided in the oracle user's home directory. The database does not use systemd services by default in this image.

Start the database and listener:

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

Stop the database and listener:

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

Check listener status:

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

Scripts and Log Files

Script/Log	Path	Description
initial_boot_update.sh	/stage/scripts	Updates the OS with the latest packages on first boot
initial_boot_update.log	/stage/scripts	Output log for the boot update script
oracle-database-credentials.log	/stage/scripts	Oracle Database SYSTEM user credentials
setEnv.sh	/home/oracle	Sets Oracle environment variables for sqlplus and other tools
start_all.sh	/home/oracle	Starts the XE database and Oracle Listener
stop_all.sh	/home/oracle	Stops the XE database and Oracle Listener

On Startup

An OS package update script runs on first boot to ensure the image is fully up to date. You can disable this by removing the script and its crontab entry:

sudo rm -f /stage/scripts/initial_boot_update.sh

sudo crontab -e
# Delete the following line, save and exit:
@reboot /stage/scripts/initial_boot_update.sh

Troubleshooting

Cannot connect via SSH

Verify the VM is in Running state in the Azure Portal
Check that port 22 is allowed in the Network Security Group
Ensure you are using the correct username: azureuser
Verify your SSH key matches the one configured during deployment

Oracle Listener fails to start

Switch to the oracle user: sudo su - oracle
Source the environment: . ./setEnv.sh
Check listener status: lsnrctl status
Review the listener log at /opt/oracle/diag/tnslsnr/<hostname>/listener/alert/log.xml
Verify port 1521 is not in use by another process: netstat -tlnp | grep 1521

Database fails to start

Switch to the oracle user and source the environment
Connect to sqlplus: sqlplus / as sysdba
Check the instance status: SELECT STATUS FROM V$INSTANCE;
Try starting manually: STARTUP;
Review the alert log at /opt/oracle/diag/rdbms/xe/XE/trace/alert_XE.log

Cannot connect remotely on port 1521

Verify the Oracle Listener is running: lsnrctl status
Confirm the Network Security Group allows inbound TCP port 1521 from your IP
Test connectivity from your client: telnet <vm-ip> 1521
Confirm your SQL Developer connection uses service name XEPDB1 (not the old SID style)
Check that the listener.ora file binds to 0.0.0.0 on the VM

Security Recommendations

Restrict port access: Only allow port 1521 from trusted application servers or specific IP addresses
Change default passwords: Update the SYSTEM and SYS user passwords immediately after first login
Use strong passwords: Ensure all database user passwords meet complexity requirements
Enable auditing: Configure Oracle Database auditing to track access and changes
Encrypt connections: Configure Oracle Net Services to use SSL/TLS encryption for client connections
Limit OS access: Restrict SSH access to authorised administrators only
Review user privileges: Remove unnecessary grants and follow the principle of least privilege
Keep the system updated: Apply Oracle Critical Patch Updates and OS security patches regularly

Support

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

Email: support@cloudimg.co.uk
Website: www.cloudimg.co.uk
Product Catalogue: www.cloudimg.co.uk/products
User Guides: www.cloudimg.co.uk/guides
Support hours: 24/7 with guaranteed 24 hour response SLA