Senior Linux Systems Engineer – Remote & Secure Infra

Lumen; Concord (NH); Remote; USD 87,000 - 116,000; Full time

Job summary

Lumen is seeking a Senior Linux Systems Administrator to design, build, secure, operate, and maintain Linux-based infrastructure supporting a classified federal program. The role emphasizes advanced Linux administration, VMware and KVM virtualization, and lifecycle support.

This remote position invites candidates across the U.S. to contribute to DevOps and app-support tasks, including automation with Ansible and Python, CI/CD with GitLab, and integration with LDAP/AD, SSL/TLS, and monitoring

Qualifications

• Six or more years of experience in Linux systems, infrastructure, network, security, or platform administration.
• Advanced administration experience with Ubuntu and RHEL.
• Strong command-line proficiency, including Bash scripting and CLI-based troubleshooting.
• Demonstrated experience designing and building production infrastructure from the ground up.
• Hands-on experience administering VMware ESXi, vCenter, and vSphere.
• Experience with KVM or comparable Linux-based virtualization technology.
• Experience administering Nessus or a comparable vulnerability-management platform.
• Experience managing SSL/TLS certificates and public-key infrastructure concepts.
• Strong knowledge of LDAP, LDAPS, and Active Directory integration.
• Working knowledge of TCP/IP, routing, DNS, NTP, firewalls, switches, ports, and network troubleshooting.
• Experience with Ansible and infrastructure automation.
• Working knowledge of Python and Git.
• Experience supporting monitoring and logging tools such as Zabbix and Elastic Stack.
• Ability to troubleshoot across operating systems, virtualization, authentication, applications, and network infrastructure.
• Active TS clearance with current SSBI/T5R investigation and CI polygraph, if those remain mandatory for the program.

Responsibilities

• Design and build secure Linux infrastructure from initial requirements through production implementation and operational handoff.
• Install, configure, administer, patch, harden, and troubleshoot Ubuntu and Red Hat Enterprise Linux systems.
• Perform advanced command-line administration using Bash and standard Linux utilities.
• Administer VMware ESXi, vCenter, and vSphere environments, including hosts, VMs, templates, storage, networking, certificates, backups, and recovery.
• Build and maintain KVM-based virtualization environments and support migration between platforms.
• Provision physical and virtual servers and integrate with network, storage, DNS, NTP, directory, monitoring, backup, and security services.
• Install, configure, maintain, and troubleshoot LDAP/AD integrations, including LDAP/LDAPS, bindings, searches, groups, and trust.
• Manage SSL/TLS certificate lifecycle, including keys, requests, SANs, installation, renewal, and trust.
• Maintain Nessus vulnerability scanning infrastructure, configurations, schedules, findings, remediation.
• Maintain monitoring/logging platforms such as Zabbix and Elastic Stack.
• Troubleshoot network connectivity, routing, DNS, ports, firewalls, NAT, and security controls.
• Create and maintain automation using Ansible, Bash, and Python.
• Use Git and GitLab CI/CD to manage infra code and deployment workflows.
• Read/modify applications built with Flask or Django as needed.
• Support REST API integration between apps, infra, and network/security elements.
• Develop and maintain build guides, diagrams, and runbooks.
• Participate in upgrades, incident response, capacity planning, and lifecycle management.
• This position requires 5‑20% travel for on-site meetings and hardware servicing.

Skills

Linux system administration

VMware ESXi/vCenter/vSphere

KVM virtualization

LDAP/AD integration

SSL/TLS certificates

Nessus vulnerability management

Zabbix / Elastic Stack

Ansible automation

Python scripting

GitLab CI/CD

Flask / Django apps

REST API integration

Bash scripting

Network troubleshooting

Tools

VMware ESXi/vCenter/vSphere

Nessus

Zabbix

Elastic Stack

Ansible

GitLab CI/CD

Python

Flask / Django

Job description

Lumen is seeking a Senior Linux Systems Administrator to design, build, secure, operate, and maintain Linux-based infrastructure supporting a classified federal program. The role emphasizes advanced Linux administration, VMware and KVM virtualization, and lifecycle support.

This remote position invites candidates across the U.S. to contribute to DevOps and app-support tasks, including automation with Ansible and Python, CI/CD with GitLab, and integration with LDAP/AD, SSL/TLS, and monitoring