A major Australian telecommunications company successfully migrated over 500 CentOS, Oracle Linux, and Alma Linux servers to Red Hat Enterprise Linux (RHEL) following the discontinuation of CentOS support. The upgrades were automated using Ansible Automation Platform. The project was completed within nine months with zero unplanned downtime, ensuring continued security compliance and enterprise support for critical infrastructure.
Client Background
Our client is one of Australia’s largest telecommunications providers, serving customers across mobile, internet, and enterprise services. Their infrastructure relied heavily on CentOS for hosting customer-facing applications, billing systems, and network management platforms.
The Challenge
When Red Hat announced the end-of-life for CentOS in December 2021, the client faced a critical decision. With over 500 production servers running CentOS and other Linux distributions, they needed to migrate to a supported enterprise Linux distribution before security patches ceased. The stakes were high:
- Regulatory compliance: Telecommunications infrastructure must meet strict security standards
- Business continuity: Customer-facing services required 99.99% uptime
- Legacy applications: Several mission-critical applications had dependencies specific to CentOS configurations
- Timeline pressure: Limited window before end-of-support deadline
- Project efficiency: Budget constraints required cost control and high levels of efficiency through automation where possible.
Our Solution
We developed a comprehensive four-phase migration strategy:
Phase 1: Assessment and Planning Our team conducted a thorough infrastructure audit, identifying application dependencies, custom configurations, and potential compatibility issues. We prioritized servers based on criticality and complexity.
Phase 2: Proof of Concept We established a test environment mirroring production systems, validating RHEL compatibility and creating detailed Ansible migration runbooks.
Phase 3: Pilot Migration Twenty non-critical servers were migrated first, allowing us to refine processes and train the client’s operations team on RHEL management.
Phase 4: Production Rollout Using an automated migration toolkit and off-peak maintenance windows, we systematically converted production servers with comprehensive rollback capabilities at every stage.
Results
The migration delivered significant benefits:
- 100% successful migration of 500+ servers with zero data loss
- Zero unplanned downtime during migration activities
- 30% reduction in security vulnerability exposure within first quarter
- Enhanced support: Access to Red Hat’s enterprise support and security updates
- Future-ready infrastructure: Modern platform supporting containerization and cloud-native initiatives
Conclusion
This project demonstrates the importance of proactive infrastructure management and the value of experienced migration partners. By carefully planning and executing the CentOS to RHEL transition, we helped secure our client’s critical telecommunications infrastructure for years to come while maintaining the exceptional service reliability their customers expect.