Senior Linux System Administrator - Active Top-Secret Clearance

Role Summary:Support mission critical systems within a classified federal program.Administer Linux environments and AWS cloud infrastructure to maintain secure, highly available services.Implement automation, infrastructure as code, and compliance hardening aligned to DoD standards.Core Responsibilities:Administer and maintain Linux servers in classified and unclassified environments using RHEL, CentOS, and Ubuntu.Design, implement, and maintain AWS infrastructure including VPC, EC2, EBS, S3, IAM, CloudFormation, CloudWatch, RDS, and EFS.Automate provisioning, configuration, deployment, and patching with Ansible, Terraform, or CloudFormation.Monitor system performance, conduct root cause analysis, and implement performance tuning and capacity planning.Patch and harden Linux systems to meet DISA STIG and RMF compliance requirements.Manage users, roles, permissions, and security policies per DoD standards.Support CI/CD pipelines and DevSecOps practices using tools such as Jenkins, GitLab CI/CD, and AWS CodePipeline.Collaborate with cybersecurity teams for continuous monitoring, audit readiness, and incident response.Participate in Agile/Scrum sprints and provide infrastructure support to development and QA teams.Produce clear documentation for architectures, runbooks, IAC modules, and change records.Required Qualifications:Active Top Secret security clearance.Bachelor's degree in Computer Science, Information Systems, Engineering, or a related field, or equivalent experience.Eight or more years of hands on Linux system administration with RHEL, CentOS, and Ubuntu.Proven experience managing AWS infrastructure including VPC, EC2, EBS, S3, IAM, CloudFormation, and CloudWatch.Strong troubleshooting of networking fundamentals including TCP/IP, DNS, firewalls, and load balancers.Working knowledge of security hardening, DISA STIGs, CIS benchmarks, and RMF controls.Excellent problem solving, documentation, and communication skills.Native or bilingual proficiency in English.Preferred Qualifications:Experience with container technologies including Docker, Kubernetes, ECS, or EKS.Experience with AWS GovCloud or classified AWS regions.Certifications such as AWS Certified SysOps Administrator, AWS Solutions Architect, or RHCE.DoD 8570 certifications such as Security+ or CISSP.Exposure to monitoring tools such as Splunk, Prometheus, Grafana, or Nagios.Behavioral Competencies:Detail oriented with strong ownership and follow through in classified environments.Collaborative mindset with cross functional teams including security, development, and operations.Clear and concise communicator able to document and explain complex systems.Proactive, organized, and comfortable operating under change control and audit requirements.