Linux System Administrator (Senior) – Hybrid – JHB at Datafin Recruitment

ENVIRONMENT:

• A leading domain registration and website hosting company based in Johannesburg provides a range of online solutions that enable SMEs and entrepreneurs to establish and grow their digital presence. 
• They are seeking an experienced, hands-on Linux System Administrator to join their technical team and assume responsibility for the Linux infrastructure supporting their domain, webhosting and virtualisation services. 
• This is a highly technical role requiring direct involvement in building, administering, securing, monitoring, troubleshooting and repairing production Linux servers and the services operating on them.
• The successful candidate will work directly on customer-facing web, email, database, DNS and virtualisation systems, taking full ownership of diagnosing and resolving technical issues. 
• This role suits a hands-on technical specialist who can investigate issues directly and manage them through to resolution. Candidates whose experience is primarily in coordinating, reporting on, or managing technical work rather than performing it themselves may not be the right fit. 
• The Linux System Administrator will collaborate closely with the support, network and infrastructure teams to resolve escalations, strengthen platform stability and continuously secure and optimise the environment.

DUTIES:

• Build, configure, administer, and maintain production Linux servers across the hosting, mail, database, DNS, and virtualization estate
• Diagnose, troubleshoot, and repair Linux server and service faults, from initial symptom through to root cause and permanent fix
• Administer cPanel and WHM environments — account provisioning, packages, resource limits, migrations, backups, and restores
• Administer and tune web servers (Apache, Litespeed), including virtual hosts, caching, PHP handlers, and performance optimization
• Configure, tune, and maintain ModSecurity rulesets, balancing protection against false positives on customer sites
• Administer mail infrastructure (Exim, Dovecot) — queue management, routing, authentication (SPF, DKIM, DMARC), deliverability, blacklist remediation, and anti-spam
• Administer MariaDB — configuration, tuning, replication, backups, restores, query performance troubleshooting, and repair of corrupted databases
• Administer domains and DNS at scale — zone management, delegation, records, propagation issues, DNSSEC signing and key management, and resolver troubleshooting
• Support and troubleshoot customer web applications, including WordPress, Magento, and WooCommerce — performance, compatibility, breakage after updates, and malware cleanup
• Support PHP and Node.js applications and runtime environments, including version management, extensions, and debugging application-level faults
• Implement, maintain, and troubleshoot security controls — firewalls or equivalent, SSH hardening, patching, kernel updates, intrusion detection, and vulnerability remediation
• Investigate and remediate compromised accounts and servers, including malware removal, and identify and close the entry point
• Configure and troubleshoot network components relevant to the hosting environment, including VLANs, routing, OSPF, and BGP sessions
• Manage and troubleshoot physical server hardware — provisioning, RAID and disk failures, memory and controller faults, IPMI/out-of-band management, firmware.
• Maintain and verify backup and disaster recovery processes, including regular restore testing
• Monitor platform health and capacity, respond to alerts, and identify and address issues before they affect customers
• Respond to and resolve escalations from the support team, with clear technical communication back to them and to customers where required
• Participate in incident response — restore service, then document root cause and the corrective actions taken
• Maintain accurate technical documentation, runbooks, and configuration records
• Be available on standby after hours for incidents and respond to them
• Identify and recommend improvements to platform stability, security, performance, and automation
• Keep current with Linux, hosting, virtualization, and security developments relevant to the environment

REQUIREMENTS:

Technical Proficiencies

Proficiency and practical, hands-on work experience in:

• Apache
• Litespeed
• ModSecurity
• Exim
• Dovecot
• MariaDB administration
• cPanel / WHM
• KVM virtualisation
• PHP coding and PHP applications
• Bash scripting
• Node.js
• VLANs
• OSPF
• BGP
• DNS / DNSSEC

Skills and Experience

• 10+ years Linux experience
• 10+ years' experience in Linux server administration and troubleshooting
• 5+ years' experience in domains, web hosting, and virtualization
• Strong knowledge and proven experience in Linux server administration, troubleshooting, and repair
• Strong working knowledge of web hosting and cPanel administration
• Strong knowledge in implementing and troubleshooting web applications such as WordPress, Magento, and WooCommerce
• Strong knowledge and understanding of virtualization and KVM virtualized environments
• Strong knowledge and experience in domains and DNS administration
• Strong knowledge and understanding of internet services, security, and firewalls
• Strong knowledge and experience in server hardware management and troubleshooting
• Strong diagnostic ability, able to work from symptom to root cause methodically under pressure, on unfamiliar systems, with incomplete information

Education / Qualifications

• Relevant IT qualification, or equivalent demonstrable hands-on experience
• Panel University Certified (advantage)
• Linux certifications such as RHCSA, RHCE, LFCS, or LPIC (advantage)
• Networking certifications relevant to routing and switching (advantage)
• Continuous learning/training

ATTRIBUTES:

• Ability to work autonomously, take ownership of problems end to end, and see them through without supervision
• Sound judgement on risk and change on production systems, and the discipline to document what was changed and why
• Ability to communicate technical detail clearly to non-technical colleagues and customers
• Willingness to be on standby after hours for incidents and respond to them
• Valid driver's licence and own transport (advantageous, for data centre attendance)