Ian Cotter-Llewellyn, Developer in Dublin, Ireland
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Ian Cotter-Llewellyn

Verified Expert  in Engineering

Systems Developer

Dublin, Ireland
Toptal Member Since
July 8, 2021

Ian is a senior Linux systems engineer with over two decades of experience producing web apps, developing APIs, coding mission-critical broadcast control systems, and designing on-premise and cloud-based cluster solutions. Ian's clients range from enterprises such as RTÉ, Ireland's national broadcaster, to small, lean startups. His ever-growing tool belt encompasses the full stack — Terraform and Kubernetes to workload troubleshooting. He's happiest when delivering solutions for his clients.


Amazon EKS, APIs, Amazon Web Services (AWS), Autoscaling Groups, Amazon EC2...
RTÉ Group
Management, IT Support, Communication
RTÉ Group
Audio, Python 3, Bash Script, Amazon Web Services (AWS), Cisco, Dante...




Preferred Environment

Python 3, Kubernetes, Terraform, Let's Encrypt, Amazon EC2, Amazon EKS, Amazon RDS, Networking, SSL Certificates, GitHub

The most amazing...

...feeling comes when back-out plans for a large-scale, high-impact project cut-over are superseded by the flawless execution of the cut-over plan itself.

Work Experience

DevOps Engineer

2019 - PRESENT
  • Built hosting infrastructure and CD pipelines capable of releasing dozens of web application iterations per day, serving 1,000+ daily online clients.
  • Onboarded by clients to provide design documentation that bridged the gap between clients' own technical knowledge and third-party integrators or software vendors.
  • Developed working proof-of-concept implementations for various early-stage business development strategies. These include public microsites and internal workflow improvement tools.
  • Laid infrastructure foundations for further system development and application deployments, including provisioning storage, scheduling backups, autoscaling policies, and role-based access control.
Technologies: Amazon EKS, APIs, Amazon Web Services (AWS), Autoscaling Groups, Amazon EC2, Requirements, Diagrams, Continuous Delivery (CD), Proof of Concept (POC)

Broadcast Operations First Line Response Manager

2018 - 2019
RTÉ Group
  • Implemented a regime of business continuity rehearsals to ensure all members of the support team were familiar with the steps of the disaster scenario playbooks.
  • Coordinated troubleshooting efforts of the local support team and Avid support to workaround and resolve a major post-upgrade newsroom playout bug.
  • Investigated weather graphics issues that led to missed and delayed weather bulletins. Familiarized with and standardized bulletin preparation procedures. Liaised with ChyronHego support and Imagine Communications vendors to eradicate problems.
  • Reduced occurrences of schedule overruns and commercial breaches through the use of Six Sigma instance analysis.
Technologies: Management, IT Support, Communication

Transmission Control Supervisor | Radio

2012 - 2017
RTÉ Group
  • Managed a highly skilled team in charge of providing operations support, technical maintenance, and development of production tools and workflows for live broadcasting across nine national radio services. Prepared budgets and executed capital plans.
  • Modernized audio infrastructure, transitioning to high-bandwidth audio-over-IP (AoIP). Designed redundant networks to achieve end-to-end latency of less than three milliseconds.
  • Led control system software development to perform real-time, automated control of the infrastructure.
  • Led the technical group for the national, industry-wide Irish Radioplayer project that saw 38 radio stations across Ireland join forces in one mobile app. Liaised with stations to ensure streams and sites conformed to their technical obligations.
  • Implemented Amazon Alexa flash briefing skill for use as the default news provider for devices sold in Ireland. Worked to Amazon's launch-date deadline, ensuring that the production values were upheld, as well as intuitive CMS and reliable delivery.
  • Supported the visual radio pilot for RTÉ Radio and led implementation for long-term studio and rack-room installs. Created an infrastructure template that could be repeated for further studios, allowing the overall system to scale up with demand.
Technologies: Audio, Python 3, Bash Script, Amazon Web Services (AWS), Cisco, Dante, Laravel Livewire, WheatNet-IP

Project Engineer | Radio

2005 - 2012
RTÉ Group
  • Designed bare-metal, on-premise, Red Hat clusters to handle radio production database with all music, audio clip, and radio production metadata. Cluster configuration storage variations: fiber, DRBD, and cloud storage. Provisioned with kickstarts.
  • Developed compliance logger replacement for nine radio services, including network and storage redundancy and a simple, fast API for retrieving the stream segments. The system was so popular it was used for long-term archive and program production.
  • Initiated a project to overhaul the national radio website to modernize its design and make it mobile responsive in advance of Google's Mobilegeddon. Managed third-party design and handled delivery and deployment with local front-end devs.
  • Homogenized audio production for the web. Designed an automated, configurable client to download, normalize, transcode, deliver on-demand, and catch up programs for listeners. Built on Python and Django on top of Virtualenv and a Postgres cluster.
Technologies: JavaScript, PHP, CSS, Linux, Distributed Replicated Block Device (DRBD), Bash Script, Python 3, Fault Tolerance, Database Replication, APIs

AudioFile | Broadcast Recording System

A bi-located, fault-tolerant audio recording, storage, and serving system operating 24/7/365 providing mission-critical service to thousands of users.

I architected the solution within the confines of the corporate environment. This included clustered VMware origin servers with SCSI attached shared storage presented as RDMs to the origin VMs and consumed as LVM PVs.

Designed the API and the front end (a web-based audio player), outsourced the front end build, and developed the back end myself.

The back end consisted of a PHP codebase for the API, which leveraged server-side-binaries to slice up the audio and stream it to the client. I also wrote a Python program to synchronize the central storage with the satellite recorders every 750 milliseconds using HTTP range requests. This turned out to be extremely efficient and was rolled out further to a separate radio production system to use excellent reliability.

Instrumented the system so that operators could monitor various parameters, including disk usage and sync latency.

The API was designed to be used by other applications to automate tasks (cut audio for publication online), provide long-term archive access, and facilitate the production of future radio programs.

Continuous Delivery Three-tier Web Service

Developed a continuous delivery (CD) pipeline and infrastructure-as-code (IaC) to provision a three-tier, cloud-based web app capable of serving thousands of back-end requests per second. The stack was operated on by three distinct roles — DevOps engineers, operations teams, and app developers.

Stack included monitoring (Prometheus) and log collection (Grafana Loki) as well as automated backups (AWS Backup) of these metrics, logs, and the application's underlying database (Postgres).

I used Github actions to provide continuous delivery of code triggered by pushes and pull requests that include modifications to the application codebase. The actions include building a Docker image for the front-end or back-end service as necessary, testing the new image, tagging it with the appropriate version number (Docker Hub), and initiating a production rollout of the upgraded version on Kubernetes (Amazon EKS).

We automatically secured all public endpoints with TLS (cert-manager and Let's Encrypt).

Scaling was handled semi-automatically at the client's request by providing a simple management script that an in-house Ops team could call to scale up and down as they saw fit. The cluster then managed to scale AWS resources as necessary.
2001 - 2004

Bachelor's Degree in Electrical and Electronic Engineering

Queen's University Belfast - Belfast, Northern Ireland


Six Sigma Yellow Belt

University of Limerick


Red Hat Certified Engineer

Red Hat


Linux From Scratch Builder



Let's Encrypt, GitHub, Terraform, Git, Amazon EKS, Distributed Replicated Block Device (DRBD), Helm, Grafana, Certbot


Bash Script, Python 3, Python, JavaScript, PHP, CSS


Linux, Red Hat Linux, Kubernetes, Amazon EC2, Docker, Amazon Web Services (AWS), Apache2


DevOps, Management, Continuous Delivery (CD)


Laravel Livewire


Database Replication


SSL Certificates, Linux Internals, Amazon RDS, Networking, Software, IT Support, Communication, Audio, Fault Tolerance, APIs, Lean Six Sigma, Cisco, Dante, WheatNet-IP, Relational Database Services (RDS), Prometheus, Autoscaling Groups, Requirements, Diagrams, Proof of Concept (POC)

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