Introduction
Oracle Linux 9 is a modern, enterprise-grade Linux distribution designed for performance, security, and long-term stability. Built from the same upstream sources as Red Hat Enterprise Linux 9, it delivers binary compatibility while adding Oracle-specific enhancements such as the Unbreakable Enterprise Kernel (UEK), advanced performance tuning, and strong integration with cloud and enterprise workloads.
Microsoft Azure provides a highly scalable and globally distributed compute platform, making it an excellent environment for running Oracle Linux 9 for production systems, development environments, CI/CD pipelines, and performance-sensitive workloads. When deployed correctly, Oracle Linux 9 on Azure can deliver predictable performance, a strong security posture, and streamlined operations.
In this article, we explore best practices for running Oracle Linux 9 on Microsoft Azure, covering virtual machine selection, storage architecture, networking, security hardening, performance tuning, patching strategies, monitoring, backup, and automation. Whether you are migrating existing workloads or building new cloud-native applications, these guidelines will help you create a stable and production-ready environment.
Somewhere during your initial setup and planning, you will encounter the concept of an Oracle Linux 9 image in Microsoft Azure, which serves as the foundation for consistent, repeatable deployments across environments.
Choosing the Right Azure Virtual Machine Size
Selecting the appropriate Azure virtual machine (VM) size is critical for performance, cost efficiency, and scalability.
CPU Architecture Considerations
Oracle Linux 9 runs reliably on multiple CPU architectures available in Azure:
x86_64 (Intel / AMD)
Best suited for legacy applications, commercial software, and workloads requiring maximum compatibility.
ARM64 (Azure Ampere Altra-based VMs)
Well-suited for modern, cloud-native workloads, microservices, and applications compiled for ARM, offering strong price-performance benefits.
Always validate application compatibility before deploying ARM-based virtual machines in production.
VM Families
Common recommendations include:
- General purpose (Dsv5, Dav5) for balanced workloads
- Compute optimized (Fsv2) for CPU-intensive tasks
- Memory optimized (Esv5, Edsv5) for databases and in-memory workloads
Enable Azure Monitor metrics and periodically review utilization to right-size your VM selections.
Storage Best Practices
Storage design directly impacts system performance, scalability, and reliability.
OS Disk Configuration
- Use Premium SSD v2 or Standard SSD for predictable boot and system performance
- Allocate sufficient disk throughput for package updates and system operations
- Use XFS, the default and recommended filesystem for Oracle Linux 9
Data and Application Disks
- Separate application data from the OS disk
- Use dedicated managed disks for databases, logs, and large datasets
- Enable Azure Disk Encryption for data at rest
- For I/O-intensive workloads, use Ultra Disk or high-performance Premium SSD configurations
Networking Configuration
Proper networking design ensures security, low latency, and scalability.
Virtual Network and Subnet Design
- Deploy virtual machines in private subnets whenever possible
- Expose services through Azure Load Balancer or Application Gateway
- Use Azure NAT Gateway for controlled outbound internet access
Network Security Groups (NSGs)
- Apply the principle of least privilege
- Allow only required inbound ports (for example, 22 for SSH, 443 for HTTPS)
- Restrict SSH access to trusted IP ranges or use jump hosts
- Apply NSGs at both subnet and NIC levels when appropriate
Accelerated Networking
Enable Accelerated Networking on supported VM sizes to achieve lower latency and higher throughput. This is strongly recommended for production workloads.
System Hardening and Security
Security should be integrated into your Oracle Linux 9 deployment from the beginning.
SELinux
Oracle Linux 9 runs with SELinux enabled and enforcing by default:
- Keep SELinux in enforcing mode
- Use semanage and custom policies rather than disabling SELinux
- Validate application compatibility early in the deployment lifecycle
Firewall Configuration
Use firewalld to manage host-level firewall rules:
- Define zones appropriately
- Avoid opening unnecessary ports
- Keep firewall configuration consistent and documented
User and Access Management
- Disable password-based SSH authentication
- Use SSH key authentication exclusively
- Grant sudo privileges only where required
- Rotate SSH keys regularly
Package Management and Updates
Maintaining up-to-date systems is essential for security and reliability.
DNF and Repositories
Oracle Linux 9 uses dnf for package management:
- Perform regular updates using dnf update
- Pin critical packages if required for application stability
- Remove unused packages to reduce the attack surface
Kernel Strategy
Oracle Linux offers two supported kernels:
- Unbreakable Enterprise Kernel (UEK) – optimized for performance and modern workloads
- Red Hat Compatible Kernel (RHCK) – designed for strict compatibility requirements
Choose one kernel strategy and standardize it across all environments to simplify operations and troubleshooting.
Performance Tuning
While default settings are production-ready, tuning can improve performance for demanding workloads.
System Limits
- Adjust ulimit values for file descriptors and processes
- Tune sysctl parameters for networking and memory usage
- Disable unnecessary services to reduce system overhead
Disk and I/O Optimization
- Align filesystem settings with managed disk performance characteristics
- Use noatime mount options where appropriate
- Monitor disk latency using tools such as iostat and iotop
Monitoring and Logging
Operational visibility is essential for maintaining system health.
Azure-Level Monitoring
- Enable Azure Monitor metrics and diagnostic settings
- Track CPU, memory, disk, and network usage
- Configure alerts for critical thresholds
OS-Level Monitoring
- Use tools such as top, htop, vmstat, and sar
- Centralize logs using Azure Monitor Logs or an external log aggregation solution
- Implement log rotation to prevent disk exhaustion
Backup and Disaster Recovery
A solid backup strategy protects against failures and operational errors.
Disk Snapshots
- Schedule regular managed disk snapshots
- Automate snapshot retention policies
- Periodically test restore procedures
Image Strategy
- Create custom Azure images after system hardening and configuration
- Version images clearly
- Favor immutable infrastructure practices where possible
Automation and Infrastructure as Code
Manual configuration does not scale in cloud environments.
Cloud-Init
Use cloud-init to automate:
- Initial package installation
- User and SSH key configuration
- Baseline system hardening
Configuration Management
Tools such as Ansible, Chef, or Puppet can:
- Enforce consistent system configuration
- Apply security baselines
- Minimize configuration drift
Immutable Deployments
Instead of modifying live systems:
- Build updated images
- Deploy new virtual machines
- Decommission old instances
This approach improves reliability, security, and rollback capability.
Compliance and Governance
Many organizations must meet internal or regulatory compliance requirements.
- Document system configurations and changes
- Enforce patching and update policies
- Use managed identities instead of embedded credentials
- Audit access and configuration changes regularly
Oracle Linux 9 integrates well with Azure governance and security services when deployed correctly.
Conclusion
Running Oracle Linux 9 on Microsoft Azure is a strong foundation for both enterprise and cloud-native workloads. By selecting appropriate VM sizes, designing secure networking, hardening the operating system, and embracing automation, you can build a reliable, secure, and scalable infrastructure.
Success depends on standardization and repeatability—using well-defined images, consistent configuration practices, and continuous monitoring. When these best practices are applied, Oracle Linux 9 becomes an excellent platform for modern workloads on Azure, capable of supporting everything from simple web applications to mission-critical enterprise systems.
With the right architecture and operational discipline, Oracle Linux 9 on Azure can remain secure, performant, and easy to manage over the long term.
