Hire Me

From Leo's Notes
Last edited on 6 December 2025, at 06:39.

Hello!

I am a senior Linux administrator with 19+ years of experience managing Linux systems including HPC, cloud, and on‑prem Linux desktop and server infrastructure. My recent experience has proven my expertise in automating large‑scale environments to support scientific research, teaching & learning, and enterprise workloads, as well as custom solutions for metrics gathering and report generation. I am adept at translating business needs into reliable, scalable solutions while mentoring teams and driving process improvements.

Core competencies

  • Operating systems: 19+ years of server experience with Red Hat-based OSes (CentOS, Rocky Linux, Fedora), Debian, Ubuntu. Experience with Solaris and FreeBSD
  • Automation & configuration: Ansible, Terraform, Packer, SaltStack, Puppet, GitLab CI/CD
  • Container Platforms: Docker, Kubernetes, Apptainer
  • Cloud & Virtualization: AWS, OCI, VMware vSphere/Automation, Proxmox, CloudStack
  • Programming & Scripting: Bash, PowerShell, Python, Java, C#, PHP, C
  • Databases: MySQL, MariaDB, PostgreSQL, SQLite, InfluxDB / Flux, ElasticSearch
  • Monitoring: Grafana, InfluxDB, Telegraf, ELK stack
  • Networking: HP and Cisco switches, software firewalls, NAS systems
  • Security: Kerberos, LDAP, PAM, PKI, log‑based threat hunting, network packet analysis
  • Hardware Platforms: x86_64, ARM64, Sun, Dell, HP, IBM Tape Library (TS4500)

Professional experience

HPC System Administrator - University of Calgary (December 2019 - Present)

One of three lead administrators of HPC resources at Research Computing Services (RCS). Tasked with the successful transition of the 1PB+ GPFS/Tape storage system at the Centre for Health Genomics and Informatics (CHGI) at the Cumming School of Medicine (CSM) into RCS's service offering. Streamlined over 1000 HPC cluster nodes to Ansible, automated account vending, and implemented a robust metrics collection and reporting system.

Major accomplishments include:

  • Transitioned our HPC cluster of over 1000+ nodes to Ansible and automated configuration deployments and leveraging CI/CD pipelines to automate account provisioning and systems configuration.
  • Automated HPC cluster usage report generation from various sources (hardware sensors, servers, network gear) into InfluxDB and visualize CPU, memory, storage usage by users, department, and faculty with Grafana to drive proactive capacity planning.
  • Developed custom log-parsing scripts to ingest Slurm jobs, system metrics, and audit logs for reports, alerting, and governance reporting.
  • Created RCS's Open OnDemand portal and containerized scientific apps, improving user productivity and easing the learning curve for users new to HPC.
  • Implemented and maintained CloudStack as a private cloud solution and authored training materials and one-on-one workshops with researchers.
  • Facilitated researchers into RCS managed AWS Control Tower environment while ensuring institutional security compliance and governance

Infrastructure Automation & Containers Specialist - University of Calgary (December 2018 - December 2019)

Part of a newly created team tasked with spearheading the University's first internal Kubernetes as a service platform and VMware vRealize Automation pipeline for delivering virtual machines for secure research workloads.

Achievements include:

  • Ensured the smooth operation of 8 CoreOS Tectonic Kubernetes clusters while coordinating internal web team’s transition into our in-house Kubernetes infrastructure
  • Evaluated Pivotal Enterprise PKS and Red Hat OpenShift as a new managed Kubernetes solution
  • Built and migrated custom applications into a containerized environment using Helm charts
  • Automated VM deployments on the University's private cloud with VMware vRealize, enabling zero-touch VM provisioning from ServiceNow and integration with Red Hat Satellite
  • Authored change-management documentation compliant with ITIL and IT policies, ensuring audit readiness

Technical Systems Analyst for Linux Desktop - University of Calgary (July 2018 - November 2018)

I spearheaded the standardized Linux desktop environment for the Customer Technology Services (CTS) group at the University of Calgary. Building on my experience from the Computer Science department, I transitioned and unified disparate Linux desktop infrastructures across various departments into a single standardized solution managed by central IT.

  • Deployed Foreman, an open-source alternative to Red Hat Satellite, for unattended Linux deployments supporting Fedora & Kali Linux on both Intel and ARM based computers. Used by over 250+ Linux workstations for the Department of Computer Science
  • Deployed infrastructure as code and CI/CD pipeline based on Puppet and GitLab for automated configuration management
  • Created and updated custom Linux based packages used by teaching and research
  • Consulted with faculty members to ensure software requirements required for teaching are met
  • Authored support materials for technical staff in Computer Science

Linux System Administrator - University of Calgary (October 2012 - July 2018)

I was a Linux system administrator that oversaw over 400 Linux-based servers and workstations for the department of Computer Science at the University of Calgary. I ensured that all teaching and learning needs were met with a consistent and reliable computing environment while providing end-user support for faculty, staff, and students within the department.

  • Spearheaded a rewrite of the departmental firewall and intrusion detection system. Firewall rules were parsed and pattern matching was deployed to block malicious traffic patterns from reaching the department network
  • Modernized over 400 machines from an aging CFEngine configuration management system to SaltStack, simplifying systems provisioning and account management
  • Enabled visibility into lab usage with custom machine telemetry data, integrated automatic data polling of student data and courses from the IT data warehouse, and data dashboards
  • Deployed Logstash + ElasticSearch for internal logging of both Windows and Linux servers and workstations
  • Converted applications on dedicated servers into containerized solutions, reducing server count by half and ensuring new teaching and research apps are supported, including WebCAT, OwnCloud, Moodle.
  • Authored support documentation and end-user guides with a focus on undergraduate student experience

C# Developer - Onstream Pipeline Inspection Ltd. (2011 - 2012)

I was one of two C# developers at a pipeline inspection company, developing their new version of pipeline analysis software.

  • Debugged existing in-house software written in Borland C++ on Windows while working with low-level hardware interfaces with custom in-house pigs
  • Developed analysis software using C# .NET4 to visualize pipeline data

Freelance Web Developer & Designer – Steamr (2005 - 2015)

I was a freelance web designer and developer for over 20 clients across North America with custom web designs and applications. I was responsible for ensuring projects are completed on-time, on-budget and satisfies client requirements.

  • Consulted with clients on requirements, budget, and timelines. Delivered frequent deliverables and project updates to ensure transparency
  • Created and deployed custom web designs from scratch using Adobe Photoshop, Illustrator, Notepad++ while ensuring full compatibility across half a dozen web browsers

Server Administrator - SwiftHost.net (2004 - 2012)

Operated a web hosting company with a partner with a focus on affordable shared and reseller hosting. Servers utilized were based on the LAMP stack along with the use of the cPanel control panel.

  • Managed production servers hosting over 400 individual websites
  • Responsible for responding to customer support tickets and provided technical support for a wide range of web applications
  • Performed security audits and server hardening, firewall and intrusion detection in a shared hosting environment

AS/400 Night Operator - Calgary Programming Factory (2007)

I worked as night operator as part of the AS/400 support team at the Calgary Programming Factory for The Sovereign General Insurance Company.

  • Operated the tape backup system, ensuring backups are valid and without errors.
  • Operated the AS/400 system to print system logs and claim cheques
  • Performed a feasibility study on moving existing projects based on JSP servlets to ASP.NET

Education & Training

  • Bachelor of Science in Computer Science, University of Calgary, 2011
    • Notable courses: CPSC 550; System Administration with Darcy Grant, Wayne Pearson (2010 – 2011)
  • Red Hat Satellite 6 Training
  • VMware vSphere 6.7
  • VMware vRealize Automation 6.5

Personal

  • Languages: English, Cantonese
  • Interests: system infrastructure, systems security, game development, electronics & hardware tinkering