DevOps and Cloud lead engineer at Samsung building and operating cloud services to serve billions of devices.Managed the DevOps team consist of 18 engineers for automating infra tasks and higher cadence releases for various products.Provided catalog of self services for engineers to do their development and testing easier and faster with large scale on-demand build/test clusters using Kubernetes● Self Service InfrastructureTo address hundreds of Developers/QAs requests, we developed self services to reduce overhead caused from communication and manual work.- Developers can Turn up entire cluster with one click for services for doing development and functional testing with expiry date for easier development and testing with less cost.- Built scheduler for running shared load testing/functional tests so that engineers don't have to run their own test infrastructures- Provided Service Catalog for engineers to address infrastructure needs such as adding DNS, Account, Grant access and create resources by themselves.● CI/CD- Github Enterprise for CI by designing branch strategies for releasing various products.- Customized Prow(Kubernetes CI infrastructure) that leverages K8S clusters for doing build/test on containers efficiently.- Built pipelines using Jenkinsfile and shared library to automate processes exist in Samsung.● Migrated monolithic services to Microservices for frequent releases by adopting App Mesh (Envoy) and writing a custom operator to drain/undrainstateful services.● Monitor K8S clusters and containers using Prometheus and Alarm manager. Now moving on to build auto healing system based on these monitoring infrastructure using AWS Lambda.● Infrastructure as Code for deploying services on AWS.- Terraform for provisioning cloud resources and turn up services using custom provider.- Configuring provisioned resources using Ansible Tower to centralize audits and centralized execution- Automated turn up Openshift Cluster using Ansible

I have worked on building the teams dedicated to reliable deployment infrastructure for millions of servers, self healing remediation system, both front/backend for workflow design/management service for automating various processes at Facebook and building both front and backend for capacity planning for Facebook Datacenter.Highly specialized in React.js/Flux/complex 2D graphic programming, global load balancing for Facebook/Yahoo scale distributed services by utilizing L4/L7 load balancers, GSLB, BGP and ECMP.● Migration Project for configuration management system from CFEngine to Chef for over 100tiers.● Migration project from F5 load balancer to IPVS Linux load balancer● Replaced existing DNS resolver to Unbound resolver to increase the DNS reliability● IPV6 Migration including redesigning POP sites.● built both UI and backend for Workflow engine system that automated Cluster/Network/Data Infra turnups, Firedrill clusters, Datacenter site construction projects, Kernel/BIOS upgradeand many others that cut over significant time at Facebook.● Ability to develop sophisticated tools in React.js/Flux and Hack including workflow engine UIto release engineering tools.● I’ve been leading kernel/bios upgrade across fleet which is about half million servers, whichend up understanding great deal of our infrastructure and services.● Automatic Remediation system that remediate problems across our servers that replaced atleast 200 people at Facebook.● Developing tools for Datacenter operation such as space and power design and workflow automation for process such as rack delivery and retrofit tasks.

Major Achievements- Deployed Diablo 3, Starcraft 2, World of Warcraft online game services and NextGen battle.net infrastructure and web sites.- Capacity Planning for Reliable NextGen battel.net sites- Maintain Battle.Net, World of Warcraft and StarCraft2 as world most stable game service.- Implemented Korea hardware upgrade project (HP 3000+ blades, HP-RX, EMC VMax, DMX and CLARiiON).- Improved Team members’ technical skills by Perl, LINUX Training and sharing resource through customized Drupal.- implemented Ticketing Strategy and practiced SLA on tasks and outages.Speciality Gained- Redhat Cluster Suite (Cluster, Multipath, GFS and LVS) - Spring Framework and JAVA multi-threading- Redis, Memcached Administration- SAN Networking (Brocade Switch, EMC Storage)- Low Latency Infrastructure- Apache, Tomcat Administration and Deployment- Puppet config management system- Bulk Mail infrastructure using sendmail and cache resolvers

I was in charge of implementing New Yahoo Infrastructure such as GSLB, Cache Farm and Automatic Server deployment/Configuration.My routine work at Yahoo follows as below:- Improve automatic Server Deployment and Troubleshooting issues.- LINUX, BSD, Windows system administration and troubleshooting.- Maintain website load balancing with L4 switch(Alteon and Foundry)- Maintain Yahoo's Anycast DNS servers and Root Name servers- GSLB control with Akamai EdgeSuite and Yahoo's New GSLB service.- System Monitoring with Gomez, Nagios, MRTG nd RRDTool.- Brocade SAN switch configuration, zoning and health check with SANHealth.- Checking system security and patching bugs by Siebel and Bugzilla ticketing system.- Build script for system checking and patching tools by Perl and Shell.- Performance Engineering tools for PEG Yahoo- Documentation about new technical information and work policy in TWIKI.

Developed Web Log Analysis Service for Major Sites in KR with massive web traffics.MySQL Administration for Replication and NDB cluster.Reneweled current Web Analytic Service to leverage Web 2.0 characteristics.- Redesigned current web analytics service interface with ExtJS javascript library.- Automated generating tremendous number of Web Analytic reports for customers in Excel files.

- LAMP(linux, apache, mysql, php) developer- Drupal Customization and Administration- Service and UI Designer- implemented BASIC language interpreter in perl to port legacy accounting program CPC used to web environment.