Senior/Staff Engineer for CloudLinuxOS (remote-only, Europe & CIS)

CloudLinux is a global remote-first company. We are driven by our principles: do the right thing, employees first, we are remote first, and we deliver high volume, low-cost Linux infrastructure and security products that help companies to increase the efficiency of their operations. Every person on our team supports each other and does what we can to ensure we are all successful.

CloudLinuxOS, our flagship product, runs on over 80,000 production servers today, powering over 50 million websites, and is recognized as the best OS for security and efficiency in a shared hosting environment. CloudLinuxOS increases server density and enhances security, thus reducing operating costs, decreasing churn rates, and increasing profitability.

Check out our website for more information: https://www.cloudlinux.com/

We are seeking a talented Senior/Staff Engineer to join our engineering team. You will work on both web optimization (web server performance, request handling, web infrastructure) and CloudLinux core features optimization related to resource limitation (LVE - Lightweight Virtual Environment, MySQL Governor) and isolation and protection of file system (CageFS), providing technical leadership across multiple optimization domains.

Key qualities we're looking for:

• Product and architectural visionary - ability to see the big picture and drive product direction through technical excellence.
• Game changer - can take initiative and make proposals that change solutions and technical direction.
• Universal engineer - versatile and adaptable, comfortable working across different domains and technologies.
• High initiative - proactive in identifying opportunities and driving improvements.
• High performance - consistently delivers exceptional results and exceeds expectations.
• Advanced algorithmic optimization - ability to design and implement alternative, more efficient algorithmic approaches to solve complex technical problems.
• Adept at using AI - leverages modern AI tools and techniques to enhance productivity and solutions.
• Results-driven and goal-oriented - focused on delivering measurable impact and achieving strategic objectives.

Responsibilities

Web Optimization:

• Optimizing web performance - developing and implementing solutions to improve web server performance, request handling, and overall system efficiency, using benchmarking and measurements to validate improvements.
• Working with web servers - configuring, optimizing, and extending Nginx, Apache, and LiteSpeed.
• Optimizing PHP handlers and web request processing - analyzing and enhancing the performance of different PHP handlers and data transfer mechanisms for processing incoming web requests.
• Architecting web infrastructure - designing scalable, high-performance web systems and infrastructure solutions.
• Ensuring web security - implementing security measures to protect against web attacks and strengthen web server security in production environments.
• Database optimization - working with MySQL and MariaDB to optimize queries, improve performance, and ensure reliable database administration for web applications.
  

CloudLinux Core Features Optimization:

• Maintaining and enhancing LVE (Lightweight Virtual Environment) - working on resource limits, CPU throttling, memory limits, I/O limits, and other LVE-related features.
• Maintaining and enhancing MySQL Governor - working on database resource limitation and optimization.
• Maintaining and enhancing CageFS - working on file system isolation, user isolation mechanisms, and security boundaries.
• Developing new features for Limits - designing and implementing new resource limiting mechanisms and improvements to existing limit systems.
• Developing new features for Isolations - creating new isolation technologies and enhancing existing isolation mechanisms for better security and performance.
• Architecting system-level solutions - designing scalable, high-performance system-level solutions for resource management and isolation.
• Working with system internals - deep involvement with Linux system calls and system-level programming.
  

Cross-Cutting Responsibilities:

• Leading technical initiatives - making proposals that change solutions and technical direction across web optimization and CloudLinux core features.
• Optimizing system performance - improving performance through profiling, benchmarking, and algorithmic optimization across both web and system-level domains.
• Making data-driven decisions - using benchmarking, profiling, and measurements to validate technical approaches and prove all technical decisions with concrete data.
• Contributing to upstream solutions - actively participating in open-source projects and contributing improvements to public codebases, upstream codebases.
• Leveraging AI tools - using modern AI tools and techniques to enhance productivity, solve problems, and improve optimization solutions.
• Mentoring and coaching engineers, conducting technical reviews, and establishing engineering best practices.
• Collaborating with cross-functional teams to define technical strategy and roadmaps.
• Troubleshooting complex production issues across web performance, limits, isolations, and system-level functionality, implementing long-term solutions.

Requirements

We are looking for someone who has:

• 6+ years of professional software engineering experience in Python, C, Go, or another major programming language.
• Experience holding senior, staff, or principal engineering positions in previous roles.
• Expert-level proficiency in programming for web optimization, tooling, automation, system-level tasks, and related web technologies.
• Web performance expertise – participation in web performance projects or development of solutions for optimizing web performance.
• System programming expertise – extensive experience with system-level programming and low-level optimization.
• Linux kernel knowledge – strong understanding of Linux kernel internals, system calls, and kernel-space concepts.
• Resource management experience – hands-on experience with resource limits, cgroups, namespaces, or similar isolation technologies.
• Strong Linux proficiency – comprehensive understanding of Linux system administration, internals, kernel architecture, and system optimization.
• High level of security knowledge – strong understanding of common web attack vectors, isolation mechanisms, and Linux security principles.
• Data-driven approach – proven ability to use benchmarking and measurements to validate technical decisions.
• Contribution to public/upstream solutions – experience contributing to open-source projects or upstream codebases.
• Architecture and design skills – ability to design scalable, maintainable, and reliable systems at both the web infrastructure and system levels.
• Excellent communication skills – ability to articulate complex technical concepts to technical and non-technical audiences.
• English proficiency at least at an upper-intermediate level.

Benefits

What's in it for you?

• A strong focus on professional development with opportunities for learning and growth:
• Interesting and challenging projects,
• Mentor and other knowledge-exchange programs.
• Fully remote work with flexible working hours, that allows you to schedule your day and work from any location worldwide.
• Paid 24 days of vacation per year, 10 days of national holidays, and unlimited sick leaves to ensure you maintain a healthy work-life balance.
• Compensation for private medical insurance.
• Co-working and gym/sports reimbursement.
• The opportunity to receive a reward for the most innovative idea that the company can patent, fostering a culture of creativity and innovation.

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