Senior Linux System Administrator
Visys Cloud Technologies
Jul 2023 - Current (3 years)
Administer and maintain over 200+ Linux (RHEL, CentOS, Ubuntu) and Windows Server (2016/2019) systems across AWS, VMware, RHV, XenServer, and bare-metal infrastructures, ensuring 99.99% uptime. Designed, implemented, and managed enterprise PKI infrastructure, including CSR generation, certificate renewal automation, trust chain management, and TLS/SSL integration for internal and public-facing services. Performed advanced system hardening, patch management, firewall configuration, and vulnerability remediation to maintain compliance with PCI-DSS, ISO 27001, and CIS benchmarks. Architected and deployed multi-region AWS infrastructure (VPC, EC2, S3, EKS, RDS, Route 53, CloudWatch, IAM), ensuring high availability, auto-scaling, and failover p