Senior System Administrator (KVM, WireGuard, Postfix, PostgreSQL, Nagios)
We are seeking a highly skilled System Administrator with a strong background in Linux systems, virtualization (KVM), and infrastructure management tools. The ideal candidate should have a minimum of 3 years hands-on experience with KVM, and solid expertise in WireGuard VPN, Postfix mail server, PostgreSQL database management, and Nagios monitoring setup. This is a mission-critical role to manage, secure, and optimize our server infrastructure and ensure high availability of internal and client-facing systems. Key Responsibilities: Virtualization & Infrastructure Management Design, deploy, and manage virtual machines using KVM (Kernel-based Virtual Machine). Perform regular backup, migration, and scaling of KVM-based instances. Configure and maintain libvirt, virt-manager, and associated tooling. Networking & VPN Configure and maintain WireGuard VPN for secure communication between distributed systems and users. Implement firewall and network routing rules in alignment with security policies. Mail Server Management Administer and harden Postfix mail servers (including TLS, SPF, DKIM, DMARC configurations). Monitor mail queues, handle spam filtering, and debug delivery issues. Database Administration Install, configure, and manage PostgreSQL servers. Perform regular backups, replication setup, tuning, and query optimization. Monitoring & Alerting Set up and maintain Nagios for system, application, and service monitoring. Define custom checks, thresholds, and notification rules. System Security & Compliance Apply regular OS and software patches. Manage user permissions, SSH access, and audit logs. Implement basic SELinux/AppArmor policies where required. Required Skills: 5+ years of experience as a Linux System Administrator. Minimum 3 years hands-on with KVM virtualization in production. Proficiency in WireGuard VPN, Postfix, PostgreSQL, and Nagios. Strong shell scripting skills (Bash, Python preferred). Comfortable with version control tools (Git), CI/CD pipelines, and infrastructure documentation. Preferred Qualifications: Experience with tools like Ansible, Terraform, or Proxmox. Familiarity with containerization (Docker) and orchestration (Kubernetes) is a plus. Knowledge of TLS/SSL certificate management. Understanding of DNS management, NGINX/Apache, and load balancing.
