Heechul Ryu
London, United Kingdom

Always interested in improving productivity. Enjoy writing stable/scalable and performant (when possible) code. Gets overwhelmed with never ending learning but always finding a way to go further. Pursuing FP style. Learning Rust. Dreaming to work on open source projects.

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CodersRank Rank
Top 2%
Based on:
Stackoverflow 4 events
Top 50
United Kingdom
Top 10
United Kingdom
Top 50
United Kingdom
Highest experience points: 0 points,

0 activities in the last year

List your work history, including any contracts or internships
Dec 2019 - Jul 2020 (7 months)
London, England
DevOps Engineer
Revolut is one of the most popular challenger banks in the UK that aims to be a truly global digital bank. As a DevOps engineer at Revolut, I:

- developed internal Prometheus + Grafana as a service with Terraform/Atlantis to support more observability of systems across various teams
- used Google Cloud Platform and Terraform to efficiently maintain scalable infrastructure
- migrated Helm 2 to 3 on live clusters considering disaster scenarios
- defused a time bomb of legacy Docker Swarm VM with carefully planned procedures and gathered necessary information to have minimal disruptions
- migrated PiPyCloud from VM to k8s to modernise infrastructure and for stability of the service
- provisioned CloudSQL with mTLSs via Terraform to improve persistency of Grafana data
- analysed and improved stability of critical network components like Nginx Ingress Controller
- maintained Python code & shell scripts & TeamCity builds to troubleshoot and improve CI/CD
- improved and created documentations via Confluence for better clarity of various human-involved tasks to enable quicker actions
- tracked and reported issues and progress via Jira for transparent information and traceability in the future
- helped engineers investigate various network issues related to GKE and VPC and proprietary system setup
- maintained and troubleshooted Kubernetes clusters to firefight and improve stability
- worked closely in a team with pull requests and code reviews via BitBucket
- communicated with developers to analyse (and supported resolution of) various infrastructure-related issues
- used HashiCorp Vault for secure credentials management
- used various GCP products such as VPC, GKE, GCS, Cloud Logging
- researched and learned new and existing technologies & solutions to solve new and existing problems
kubernetes terraform Google Cloud Platform Helm Teamcity Prometheus bitbucket grafana
May 2017 - Aug 2019 (2 years 3 months)
Gangnam-gu, Seoul
DevOps & Software Engineer
Rainist is the company behind BankSalad, a FinTech mobile app and website that enables users to take control of their assets scattered across several banks. As a DevOps engineer at Rainist, I:

- containerised all server and web apps via Docker
- heavily used Kubernetes to deal with modern Micro Service Architecture issues
- used mostly Prometheus and Grafana for monitoring clusters and apps
- used AWS services like EC2, RDS, CloudWatch, etc
- dealt with legacy VM systems with Nutanix, Ansible, Packer, Terraform, Vagrant
- analysed issues (sometimes in real-time) and fixed/patched accordingly
- documented my work for transparency and cooperation and as a stepping stone for automations
- developed helper tools for DevOps and open-sourced them
- developed DeployBot (also a SlackBot) to automate CD
- wrote tech blogs about authentications in Kubernetes
- gave a lightning talk about DevOps (an open conference that was offered by Rainist)
- interviewed tech candidates (usually for DevOps positions)
- consulted/helped (mostly) backend developers to deal with delivery/discovery issues
- researched and introduced useful technologies to dev/ops workflow
- reduced costs (auto-scaling/cost-analysing and applying cost-effective strategies)
- integrated cloud infrastructure with recently added legacy VM infrastructure
kubernetes aws Travis CI github typescript clojure ReasonML functional programming nginx prometheus grafana kafka
Oct 2016 - May 2017 (7 months)
Gangnam-gu, Seoul
Software Engineer
ChattingCat provided an instant English correction service by native-speakers via Web and mobile apps. At ChattingCat, I was responsible for:

- Web app development for both front-end and back-end via Ruby on Rails 5, Bootstrap 4, Sass, React, etc.
- DevOps via Docker and Kubernetes, AWS, Google Cloud, Azure
- maintenance of the iOS and Android apps
- Web app development on Elixir/Phoenix to allow customers to download their data due to service closure
- wrapping up & shutting down the running services due to the end of service
aws ruby on rails elixir postgresql react phoenix

Add some compelling projects here to demonstrate your experience
May 2016 - Sep 2019
A macOS app that enables you to control and use your mouse with only your keyboard
objective-c graphic design business

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