Linux System Administrator Freelance Jobs in Riverside, CA

Bowhead seeks a Linux SME to join our team on the Corona IT program. The Linux SME will provide senior-level administration, engineering, and operational support for Linux-based enterprise systems and container platforms supporting mission-critical government and DoD programs and serve as a technical authority for Linux infrastructure, container orchestration, automation, and secure system operations in classified and unclassified environments.

This position is 100% onsite.

Install, configure, administer, and maintain Linux operating systems (RHEL, CentOS, Rocky, or equivalent) across physical, virtual, and containerized platforms. Deploy, configure, administer, and sustain Red Hat OpenShift clusters, including control plane and worker nodes, storage integration, networking, and platform upgrades. Support containerized workloads using Kubernetes and OpenShift, including image lifecycle management, registry integration, role-based access control (RBAC), and namespace management. Perform system hardening, patching, and vulnerability remediation in accordance with DoD STIGs, RMF, and cybersecurity requirements, including container security best practices. Support and maintain virtualized and hyper-converged infrastructure (VMware ESXi) hosting Linux and OpenShift environments. Develop and maintain automation and Infrastructure-as-Code (IaC) solutions using Ansible, Bash, Python, and CI/CD integrations to accelerate platform provisioning and consistency. Monitor system, cluster, and application performance; troubleshoot complex Linux, Kubernetes, and OpenShift-related issues across development, test, and production environments. Implement and maintain logging, monitoring, and alerting solutions for Linux systems and OpenShift clusters. Support backup, recovery, and disaster recovery solutions for Linux systems, container platforms, and persistent storage. Collaborate with cybersecurity, networking, DevSecOps, SOC/NOC, and application teams to ensure secure, resilient, and compliant operations. Develop and maintain technical documentation including build guides, SOPs, platform architecture diagrams, and configuration baselines. Participate in security assessments, audits, inspections, and Authority to Operate (ATO) activities. Provide mentorship and technical leadership to junior Linux and container platform administrators. Provide technical briefings and system status updates to program leadership and government stakeholders as required. The Senior Linux & OpenShift Systems Administrator reports to the Program Manager or IT Lead. Other duties as assigned.

Bachelor's degree in Computer Science, Information Technology or a related field. Seven plus (7+) years of experience as a System Administrator with a strong focus on Linux systems. Senior-level administration of Linux enterprise environments Hands-on experience with Red Hat and Kubernetes Container platform security, RBAC, and compliance implementation Scripting and automation (Ansible, Bash, Python) Virtualization and enterprise infrastructure support Experience supporting mission-critical or classified systems Strong troubleshooting, documentation, and communication skills Ability to work independently and lead technical efforts

Certifications: Comp TIA Sec+ and one of the following Red Hat Certified Engineer (RHCE) or Red Hat Certified Architect (RHCA)

Preferred Qualifications: Experience in DoD, classified, or SAP environments DevSecOps and CI/CD pipeline integration experience LPIC-2 & LPIC-3 (Linux Professional Institute) Linux Foundation Certified Engineer (LFCE) Certified Kubernetes Administrator (CKA) GIAC Certified UNIX Security Administrator (GCUX)

SECURITY CLEARANCE REQUIREMENTS: Must currently hold a security clearance at the minimum Secret level.

Physical Demands:

Ability to work in data centers, secure facilities, and operational environments Must be able to lift up to 25 pounds Must be able to stand and walk for prolonged amounts of time Must be able to twist, bend and squat periodically

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