Linux System Administrator (Senior) – Hybrid - JHB

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 equiva

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