Senior Linux Systems Engineer

• Design, deploy, and manage a globally distributed fleet of Linux servers (primarily Ubuntu 24.04 LTS)
• Own the full infrastructure lifecycle, including provisioning, configuration, patching, performance tuning, and decommissioning
• Develop and maintain standardised server builds, templates, and configuration baselines
• Optimise systems for performance, reliability, scalability, and cost efficiency

• Use SaltStack extensively for:
  • Configuration management
  • Orchestration
  • Automated deployments
  • State enforcement and drift correction
• Develop automation to support rapid, repeatable infrastructure deployment across multiple providers
• Automate operational workflows and eliminate manual intervention wherever possible
• Contribute to infrastructure-as-code standards and practices

• Configure and troubleshoot complex networking environments, including:
  • IPv4 and IPv6 addressing and routing
  • Policy routing
  • DNS configuration and troubleshooting
  • Firewall management (ufw / iptables / nftables / provider-level firewalls)
  • VPN connectivity where required
• Diagnose and resolve network-level and system-level performance issues

• Work with our custom in-house monitoring and observability platform
• Monitor infrastructure health, system metrics, logs, and alerts
• Perform root cause analysis and implement long-term solutions
• Continuously improve monitoring coverage, alert quality, and operational visibility

• Collaborate with software engineering teams to integrate infrastructure with CI/CD pipelines
• Support automated deployment processes across development, staging, and production environments
• Ensure infrastructure supports rapid and reliable code deployment

• Act as a senior escalation point and SME for complex infrastructure issues
• Diagnose problems across the full stack, including:
  • Operating system
  • Network
  • Storage
  • Virtualisation
  • Provider-specific issues
• Implement permanent fixes and preventative improvements

• Identify opportunities to improve reliability, automation, performance, and cost efficiency
• Maintain clear technical documentation and operational procedures
• Contribute to infrastructure strategy and architecture decisions

You will work with technologies including:

• Ubuntu Linux (24.04 LTS)
• SaltStack
• Multi-provider cloud infrastructure, including:
  • OVH
  • Linode
  • Digital Ocean
  • Hetzner
  • AWS
  • Other global providers
• IPv4 and IPv6 networking
• Custom monitoring and observability platform
• CI/CD pipelines and automation tooling
• Virtualisation platforms including VMware, KVM and provider-managed solutions
• Dedicated physical servers

• Core Linux & Infrastructure
  • Including safe in-place upgrades for new Ubuntu LTS versions
• 5+ years of hands-on Linux systems engineering experience
• Deep knowledge of Linux internals, including:
  • System startup and systemd
  • Networking stack
  • Disk and filesystem management
  • Process management and performance tuning
• Proven experience managing large-scale Linux environments

• Strong experience with SaltStack (or equivalent transferable skill such as Ansible, Puppet, or Chef)
• Experience implementing infrastructure as code
• Strong scripting ability in:
  • Bash (essential)
  • Perl (essential)
  • Python (preferred)

• Strong practical networking knowledge including:
• TCP/IP fundamentals
• IPv4 and IPv6 addressing and routing
  • Provider failover IP’s, floating IP’s
  • IPv6 subnet routing – advanced
• DNS
  • Provider API automation for forward and reverse zones
• Firewall configuration
  • ufw
  • Iptables
  • nftables
• Network troubleshooting and diagnostics

• Experience working with cloud infrastructure providers
• Understanding of virtualised environments and underlying infrastructure

• Experience working with monitoring and alerting systems
• Strong troubleshooting and root cause analysis skills

• Experience with CI/CD tools such as Jenkins
• Experience with containerisation (Docker, Kubernetes)
• Experience with Squid or other proxy technologies
• Experience working with globally distributed infrastructure
• Experience working in performance-sensitive environments

• Strong problem-solving ability and technical curiosity
• Ability to work independently and take ownership
• Strong attention to detail
• Clear communication skills
• Ability to work effectively with engineering and product teams

We embrace diversity and inclusion and encourage our amazing team members at DemandScience to bring their authentic, fun selves to work every day. We offer a culture of innovation, mutual respect, support, and transparency.  The competitive and comprehensive benefits our team members enjoy are designed to ensure you and your family members are healthy. Check this out!

• Paid time off
• Medical provided through HMO
• Life Insurance
• Peer-Appreciation Program
• Employee Referral Program
• A fast-paced, innovative culture with an open and collaborative environment, where you can make an impact.
• Join a great organization that cares about employees!

DemandScience is proud to be an equal opportunity workplace. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, or national origin.

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Find out more at https://demandscience.com/careers/#join-the-team