Senior Linux Administrator

Key Responsibilities

• Administer, configure, troubleshoot, and maintain production and non-production RHEL and Ubuntu Linux virtual and physical servers.
• Maintain CIS-aligned security hardening, including UFW, SSH, AppArmor, PAM, auditd, and SSL/TLS configurations.
• Support security compliance and remediation using Microsoft Defender for Cloud, Azure Policy, and Azure-native security tooling.
• Manage Ubuntu patching and lifecycle activities using Ubuntu Pro, Livepatch, Extended Security Maintenance (ESM), and APT.
• Develop and maintain automation using Bash and PowerShell, including Cron jobs and scheduled processes.
• Support Azure DevOps repositories, pipelines, source control, and CI/CD workflows for Linux environments.
• Support Docker workloads running on standalone Linux VMs.
• Integrate containerized workloads with Azure Key Vault for secrets management.
• Support Azure Container Registry (ACR), including image push/pull operations and vulnerability scanning.
• Maintain SSSD-based identity integration, sudoers governance, and PAM configuration.
• Manage LVM, XFS/EXT4 filesystems, partitions, and dedicated mounts in accordance with CIS guidance.
• Perform system administration involving systemd, kernel tuning, auditd, and log rotation.
• Partner with cybersecurity teams to address audit findings, logging requirements, remediation activities, and overall security posture.
• Work independently as the senior Linux resource within a small, cross-functional IT and security team.

Required Qualifications

• 8+ years of hands-on Linux administration experience in enterprise or government environments.
• Strong experience with current Ubuntu Server LTS releases.
• Experience administering RHEL/Red Hat Linux environments.
• Working knowledge of Microsoft Azure supporting Linux VMs, including networking, Managed Identity, and Azure Key Vault.
• Experience with Azure DevOps, including repositories, pipelines, and CI/CD workflows.
• Experience administering Docker on Linux, including container secrets management.
• Advanced Bash scripting skills and working knowledge of PowerShell.
• Experience with UFW, SSH hardening, AppArmor, and SSL/TLS certificate management.
• Experience with systemd, kernel tuning/sysctl, PAM, auditd, and log rotation.
• Experience with SSSD and Linux identity/access management.
• Experience with LVM and XFS/EXT4 filesystem administration.
• Ability to independently troubleshoot and administer enterprise Linux environments.