Senior Linux System Admin

Job Overview:

We are seeking an accomplished and technically astute Level 3 Linux System Administrator to join our high-performance infrastructure team. This individual will serve as a subject matter expert (SME) on Linux systems, providing deep operational insight, advanced troubleshooting, performance tuning and capacity planning. Demonstrate a strong balance on hands-on expertise, automation mindset, and a strategic approach to system scalability, security, and lifecycle management.

Responsibilities:

• Deliver expert-level support and resolution for complex incidents and problems within the Linux ecosystem, ensuring minimal business impact and adherence to SLAs.

• Troubleshoot and resolve escalated issues in the Linux Environment.

• Proactively monitor system health, performance and capacity to ensure stability, availability and reliability.

• Perform Kernel Upgrade, patches and Vulnerability Management to ensure compliance meeting the organization standards.

• Design and enforce system hardening, access control, and security baselines aligned with the compliance framework.

• Server as escalation point and technical advisor for Level 1 and 2 administrators, develop technical runbooks and knowledge-based articles.

• Participate and lead initiatives for architectural reviews, infrastructure modernization, and enterprise risk assessments.

• Lead Major Incidents and engage with stake holders to perform Root Cause Analysis and provide permanent solutions.

 

Skills & Qualifications

• 8+ years of progressive experience in Linux Server Administration with enterprise level skills in Physical and virtual environment management.

• Deep Understanding of Linux security methodologies, Hardening procedure and best practices.

• Deep Understanding of Linux Internals – Process Management, Memory handling. Kernel Tuning, Capacity planning.

• Evaluate and maintain server storage and other IT standards for the enterprise and all supporting products and services.

• Hands on Experience with automation tools (Ansible, Chef, Puppet)

• Analyze server and storage characteristics (e.g., CPU behavior latency transmission speeds packet loss and throughput) triage and troubleshoot problems. Knowledge and experience of Root Cause Analysis (RCA) required

• Familiarity with complex multi-site and global network design multi-layered switch environment firewalls VPN Load balancers and DNS

• Familiar with the fundamentals of web application and relational database architectures

• Knowledge and writing a code and script (Shell, Python. Perl, Yaml, and / or PHP) is a huge plus.

• Knowledge with analytics and observability tools (Grafana, Kibana, Elk, Splunk, AppDynamics) is a plus

• Experience with container technologies (docker, Kubernetes, openShift, AWS, GCP).

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Education:

• Bachelor's/University degree in Computer Science/Engineering preferred or equivalent experience

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Job Family Group:

Technology

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Job Family:

Infrastructure

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Time Type:

Full time

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Primary Location:

Irving Texas United States

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Primary Location Full Time Salary Range:

$125,760.00 - $188,640.00

In addition to salary, Citi’s offerings may also include, for eligible employees, discretionary and formulaic incentive and retention awards. Citi offers competitive employee benefits, including: medical, dental & vision coverage; 401(k); life, accident, and disability insurance; and wellness programs. Citi also offers paid time off packages, including planned