SSH Equivalency Setup in Oracle Exadata – Step-by-Step Guide

Introduction

SSH equivalency is a mandatory requirement in Oracle Exadata environments. It enables passwordless SSH communication between database servers, storage servers (cells), and other Exadata components.

SSH equivalency is used during:

• Exadata deployment

• OneCommand setup

• Patching activities

• Exachk execution

• Automation scripts

• Cluster operations

This guide demonstrates how to configure SSH equivalency securely in an Oracle Exadata environment.

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Environment Details

Example Exadata Environment:

Hostname	Type
db01	Database Server
db02	Database Server
cell01	Storage Server
cell02	Storage Server
cell03	Storage Server

User:

oracle

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Step 1: Verify Connectivity

From db01, verify connectivity to all nodes.

ping db02
ping cell01
ping cell02
ping cell03

Expected Result:

64 bytes from db02
64 bytes from cell01

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Step 2: Generate SSH Key

Login as oracle user.

su - oracle

Generate SSH key.

ssh-keygen -t rsa

Press Enter for all prompts.

Verify key files:

ls -ltr ~/.ssh

Expected:

id_rsa
id_rsa.pub

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Step 3: Copy Public Key to Remote Servers

Copy public key to all target nodes.

ssh-copy-id oracle@db02

ssh-copy-id oracle@cell01

ssh-copy-id oracle@cell02

ssh-copy-id oracle@cell03

Enter password when prompted.

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Step 4: Verify Passwordless Login

Test SSH connectivity.

ssh db02 hostname

ssh cell01 hostname

ssh cell02 hostname

ssh cell03 hostname

Expected Output:

db02
cell01
cell02
cell03

No password should be requested.

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Step 5: Configure Reverse Connectivity

Perform the same steps from db02 to db01.

Generate keys:

ssh-keygen -t rsa

Copy keys:

ssh-copy-id oracle@db01

Validate:

ssh db01 hostname

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Step 6: Validate SSH Equivalency

Execute the following command from each database node.

ssh db01 date

ssh db02 date

ssh cell01 date

ssh cell02 date

ssh cell03 date

All commands should execute without password prompts.

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Step 7: Verify Authorized Keys

Check authorized_keys file.

cat ~/.ssh/authorized_keys

Ensure public keys from all participating nodes are present.

Permissions:

chmod 700 ~/.ssh

chmod 600 ~/.ssh/authorized_keys

chmod 600 ~/.ssh/id_rsa

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Common Issues and Troubleshooting

Permission Denied

Error:

Permission denied (publickey)

Solution:

chmod 700 ~/.ssh

chmod 600 ~/.ssh/authorized_keys

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Host Key Verification Failed

Error:

Host key verification failed

Solution:

ssh-keygen -R hostname

Reconnect:

ssh hostname

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SSH Timeout

Verify:

ping hostname

nslookup hostname

Check firewall configuration.

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Validation Checklist

Check	Status
SSH keys generated	✓
Public keys copied	✓
Passwordless login working	✓
Authorized keys validated	✓
Permissions verified	✓

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Conclusion

SSH equivalency is a critical prerequisite for Oracle Exadata administration, patching, and automation activities. Properly configured passwordless SSH improves operational efficiency and reduces manual intervention during maintenance and deployment tasks.

Always validate connectivity and file permissions after configuration to avoid failures during patching and cluster operations.

Steps to Create and Connect to Azure Database for PostgreSQL

Steps to Create and Connect to Azure Database for PostgreSQL

1. Create PostgreSQL Database in Azure Portal
• Go to the Azure Portal.
• Search for and select Azure Database for PostgreSQL servers.
• Click Create, then select Flexible Server option.
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2. Get Connection Information
• In the newly created server’s Overview page, copy the Server name and Username; you will need these to connect.
3. Connect Using pgAdmin
• Open pgAdmin.
• Right-click Servers and select Create > Server.
• Enter a name, e.g., azure-pg-tt.
• On the Connection tab, enter the copied hostname and username from the Azure Portal.
• Click Save to connect.
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4. Explore Created Databases
• Expand the connected server in pgAdmin. You will see 3 databases pre-created by Azure. Do not delete these.
5. Create a New Database to Use
• Right-click Databases under your server, select Create > Database.
• Name your new database, for example, mypgsqldb.
6. Run SQL Queries on Your Database
• Select your new database (mypgsqldb) and click the Query Tool icon in pgAdmin.
• Run the following SQL commands to create a table, insert records, and query data:

sql

CREATE TABLE EMP(id serial PRIMARY KEY, name VARCHAR(50),  Salary INTEGER);

INSERT INTO EMP(id, name, salary) VALUES (1, 'Jon', 15000);

INSERT INTO EMP(id, name, salary) VALUES (2, 'Doe', 15400);

SELECT * FROM EMP;

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You are now connected to the PostgreSQL database on Azure !!!!!!