Duhan Cem Karagöz
Verified Expert in Engineering
CI/CD Pipelines Developer
Dublin, Ireland
Toptal member since May 18, 2022
Cem is a skilled DevOps and back-end engineer with experience at IsBank and Siemens, specializing in both cloud and on-premise environments, including GCloud and OpenShift. He has developed and maintained applications across diverse tech stacks such as Python, Node.js, and .NET, adopting a results-driven, task-oriented approach. Cem leverages tools like Jenkins and GitHub Actions for CI/CD pipelines and uses Helm to efficiently deploy and manage cloud-based applications.
Portfolio
Experience
- Git - 6 years
- CI/CD Pipelines - 4 years
- .NET - 4 years
- SQL - 4 years
- Jenkins - 3 years
- Cloud - 3 years
- Node.js - 3 years
- Helm - 2 years
Availability
Preferred Environment
MacOS, Git, GitHub, Visual Studio Code (VS Code), Docker, Jenkins, NestJS, .NET, Google Cloud, Azure
The most amazing...
...thing I've developed is a CI/CD process for cloud environments and a multiplatform application that boosted sales by %1.3 for our clients at Siemens.
Work Experience
Senior Member of Technical Staff
VMware
- Developed infrastructure of a FedRAMP application to deploy on AWS and managed observability, logging, and scaling of the software.
- Tracked and managed the team's work via Jira and set quarterly objectives for the project and the team.
- Managed infrastructure upgrades and maintenance such as PostgreSQL, Elasticache, Kafka, etc.
- Oversaw the security and deployment of AWS and Kubernetes clusters.
- Acted as a scrum master to maintain Agile methods such as sprint, retro, etc., and managed and displayed burndown and activity charts for upper management.
Back-end Engineer
Siemens
- Developed an application on multiple platforms. Used OPC.UA communication protocol on mobile devices to connect to industrial devices for data retrieval and manipulation. Deployed applications to our customers with a private deployment structure.
- Researched and developed certain libraries for mobile applications with Capacitor and Ionic for communication protocols that did not exist during development.
- Created plug-ins with native languages of Android and iOS devices in Capacitor to use certain communication protocols, such as DeviceDiscovery and OPC.UA communicator.
- Tracked applications closed beta process with our clients through Jira, log, and metrics collection through Elasticsearch.
- Boosted sales of our OPC.UA-supported industrial devices by %1.3.
Back-end Engineer
SoftTech
- Developed an orchestrator for on-premise systems to connect with a microservice architecture.
- Created Event-driven architecture with a message broker to facilitate events on the microservice system.
- Built and maintained microservices for SonarQube, TFS, Checkmarx, Gitlab, Github, and other master microservices to collect their information.
- Measured each developer's created value with Jira, SonarQube, TFS, and Checkmarx to ensure high quality with a good output. Microservices were used to collect the information on developers, and raw values were shown on the board.
- Created a gamification system with unit tests, API tests, and security concerns to incentivize developers better and improve quality by %7.
- Developed and maintained software that checks SQL queries, runs them through security checks, and executes them on selected databases with certain backup and rollback methods.
- Cooperated with the breakdown of monolithic applications into microservice structures for containerization. Created unit tests for coverage and checked the breakdown process.
- Acted as an in-company teacher and gave multiple classes in git and DevOps.
- Deployed and monitored 127 microservice applications to different systems, including bare metal, virtual machine, and Kubernetes. Created deployments of YAML and CD processes on TFS and Jenkins.
Experience
Multiplatform Application for İndustrial Devices
DevOps Control Center and Orchestrator
The main goal was to orchestrate the CI/CD project and simplify the steps for developers. There were scalable containers in front of each program, like SonarQube, used in the CI/CD pipeline and had a Python container that managed it via the help of the master written on .NET.
Each step and log were shown on the control center for the developer so it could be fixed faster without looking for error signs on each step. The event-driven architecture was used so the system would communicate through messages and used RabbitMQ to facilitate it.
Jenkins Plugins
One is for getting usage data from current jobs in Jenkins with information like times, minutes, and max and average time used. This information is then packed in intervals of three days to be reported to upper management.
CI/CD Pipeline for Fintech Companies
We extended the shared library to be used for our pipeline steps. Used Groovy to write each step of the process like build, packaging, uploading to Nexus or Docker repository, creating a testing environment on Google Cloud, creating namespace allocating resources, creating Helm scripts to deploy the application, testing with unit and integration tests, and notifying tester for hands-on testing.
Education
Master's Degree in Computer Science
Istanbul Ticaret University - Istanbul, Turkey
Bachelor's Degree in Computer Science
Istanbul Technical University - Istanbul, Turkey
Certifications
AWS Certified Solutions Architect – Associate
Amazon Web Services
Test of English as A Foreign Language (TOEFL)
ETS
Software Qaulity and Testing
Turkcell Academy
Skills
Libraries/APIs
Node.js
Tools
Git, Jenkins, GitHub, Helm, PyCharm, Grafana, Capacitor, GitLab, Gradle, Ansible, SonarQube, RabbitMQ, Checkmarx, Cucumber, Terraform
Frameworks
NestJS, .NET, Flask, Ionic
Paradigms
REST, DevOps, Testing, Event-driven Programming, Microservices
Platforms
Docker, MacOS, Visual Studio Code (VS Code), Azure, OpenShift, Mobile, Kubernetes, Amazon Web Services (AWS)
Languages
Python 3, Python, JavaScript, C#, SQL, Java, Swift, Groovy, Bash
Storage
PostgreSQL, Google Cloud
Industry Expertise
Banking & Finance
Other
CI/CD Pipelines, Cloud, Machine Learning, Neural Networks, Shared Libraries, HTTP, APIs, Fintech, Architecture, Prometheus, OPC UA, English, QA Testing, Message Queues, Groovy Scripting, Applied Research, Argo CD
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