%------------------------------------------------------------------------------- % SECTION TITLE %------------------------------------------------------------------------------- \cvsection{Work Experience} %------------------------------------------------------------------------------- % CONTENT %------------------------------------------------------------------------------- \begin{cventries} %--------------------------------------------------------- \cventry {Site Reliability Engineer \& Infrastructure Team Lead} % Job title {Danggeun Pay Inc. (KarrotPay)} % Organization {Seoul, S.Korea} % Location {Mar. 2021 - Present} % Date(s) { \begin{cvitems} % Description(s) of tasks/responsibilities \item {Everything that matters.} \item {Designed and provisioned the entire infrastructure on the AWS cloud to meet security compliance and acquire a business license for financial services in Korea.} \item {Continuously improved the infrastructure architecture since launching the service. (currently 3.6 million users)} \end{cvitems} } %--------------------------------------------------------- \cventry {Site Reliability Engineer} % Job title {Danggeun Market Inc.} % Organization {Seoul, S.Korea} % Location {Feb. 2021 - Mar. 2021} % Date(s) { } %--------------------------------------------------------- \cventry {Founding Member \& Director of Infrastructure Division} % Job title {Kasa} % Organization {Seoul, S.Korea} % Location {Jun. 2018 - Jan. 2021} % Date(s) { \begin{cvitems} % Description(s) of tasks/responsibilities \item {Designed on-boarding process to guide new engineers, help them to focus on the right tasks, and set expectations to help them be successful at Infrastructure team.} \item {Migrated the orchestration system from DC/OS to Kubernetes which is based on AWS EKS. Managed 3 Kubernetes clusters and 300+ pods. Managed all Kubernetes manifests declaratively with Kustomize and ArgoCD.} \item {Designed and managed complex network configurations on AWS with 4 VPC and 100+ subnets. Separated the development network and operation network according to financial regulations. Established dedicated network connections from AWS VPC to partners' on-premise network based on AWS Direct Connect with secure connection using IPsec VPN. Provisioned OpenVPN servers with LDAP integration.} \item {Provisioned a observability system with Kafka, Elastic Stack(Filebeat, Heartbeat, APM Server, Logstash, Elasticsearch, Kibana). Collected log, uptime, tracing data from hosts, containers, pods and more. The ES cluster which has 9 nodes processed more than 1 billion documents per month. Wrote Terraform module to easily provision ES cluster on AWS EC2 instances.} \item {Provisioned a monitoring system with Kafka, Telegraf, InfluxDB, Grafana. Collected metrics from hosts, containers, pods and more. Wrote Terraform module to easily provision InfluxDB with HA on AWS EC2 instances.} \item {Introduced Kong API Gateway to easily connect all API microservices with a declarative management method based on Terraform and Atlantis to collaborate and audit change history.} \item {Provisioned the Directory Service for employee identity management based on OpenLDAP which guarantees HA with multi-master replication.} \item {Implemented Worker microservices consuming Kafka event topics for email, SMS, Kakaotalk and Slack notification. Developed in-house framework to easily build Kafka consumer microservice with common features including retry on failure, DLQ(Dead Letter Queue), event routing and more.} \item {Introduced Elastic APM to help distributed tracing, trouble-shooting and performance testing in MSA.} \end{cvitems} } %--------------------------------------------------------- \cventry {Software Architect} % Job title {Omnious. Co., Ltd.} % Organization {Seoul, S.Korea} % Location {Jun. 2017 - May. 2018} % Date(s) { \begin{cvitems} % Description(s) of tasks/responsibilities \item {Provisioned an easily managable hybrid infrastructure(Amazon AWS + On-premise) utilizing IaC(Infrastructure as Code) tools like Ansible, Packer and Terraform.} \item {Built fully automated CI/CD pipelines on CircleCI for containerized applications using Docker, AWS ECR and Rancher.} \item {Designed an overall service architecture and pipelines of the Machine Learning based Fashion Tagging API SaaS product with the micro-services architecture.} \item {Implemented several API microservices in Node.js Koa and in the serverless AWS Lambda functions.} \item {Deployed a centralized logging environment(ELK, Filebeat, CloudWatch, S3) which gather log data from docker containers and AWS resources.} \item {Deployed a centralized monitoring environment(Grafana, InfluxDB, CollectD) which gather system metrics as well as docker run-time metrics.} \end{cvitems} } %--------------------------------------------------------- \cventry {Co-founder \& Software Engineer} % Job title {PLAT Corp.} % Organization {Seoul, S.Korea} % Location {Jan. 2016 - Jun. 2017} % Date(s) { \begin{cvitems} % Description(s) of tasks/responsibilities \item {Implemented RESTful API server for car rental booking application(CARPLAT in Google Play).} \item {Built and deployed overall service infrastructure utilizing Docker container, CircleCI, and several AWS stack(Including EC2, ECS, Route 53, S3, CloudFront, RDS, ElastiCache, IAM), focusing on high-availability, fault tolerance, and auto-scaling.} \item {Developed an easy-to-use Payment module which connects to major PG(Payment Gateway) companies in Korea.} \end{cvitems} } %--------------------------------------------------------- \cventry {Software Engineer \& Security Researcher (Compulsory Military Service)} % Job title {R.O.K Cyber Command, MND} % Organization {Seoul, S.Korea} % Location {Aug. 2014 - Apr. 2016} % Date(s) { \begin{cvitems} % Description(s) of tasks/responsibilities \item {Lead engineer on agent-less backtracking system that can discover client device's fingerprint(including public and private IP) independently of the Proxy, VPN and NAT.} \item {Implemented a distributed web stress test tool with high anonymity.} \item {Implemented a military cooperation system which is web based real time messenger in Scala on Lift.} \end{cvitems} } %--------------------------------------------------------- \cventry {Software Engineer} % Job title {ShitOne Corp.} % Organization {Seoul, S.Korea} % Location {Dec. 2011 - Feb. 2012} % Date(s) { \begin{cvitems} % Description(s) of tasks/responsibilities \item {Developed a proxy drive smartphone application which connects proxy driver and customer.} \item {Implemented overall Android application logic and wrote API server for community service, along with lead engineer who designed bidding protocol on raw socket and implemented API server for bidding.} \end{cvitems} } %--------------------------------------------------------- \end{cventries}