Ismail Yenigul, Developer in Istanbul, Turkey
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Ismail Yenigul

Verified Expert  in Engineering

AWS and Linux Developer

Location
Istanbul, Turkey
Toptal Member Since
July 31, 2020

Ismail is a senior DevOps and SRE engineer with expertise in Linux, AWS (AWS-certified solution architect and developer, IAM, EKS, ECS, EC2, RDS, S3), Kubernetes (CKAD and CKA certified, Docker, Helm), Terraform, Terragrunt, CI/CD (Jenkins, GitHub Actions), DevSecOps (AWS Security Hub, CIS benchmarks), and SRE practices. He ensures seamless deployments, infrastructure consistency, and system reliability. Proactive and customer-focused, Ismail leaves no stone unturned to deliver quality results.

Portfolio

Freelance
Jenkins, Terragrunt, Packer, Amazon Web Services (AWS), GitHub...
Vision R&D
Security, System Administration, GitLab, Jira, Python, Git, Ubuntu...
Esys
Security, System Administration, DNS, SMTP, Red Hat Linux, Linux, LPIC-1, SSH...

Experience

Availability

Full-time

Preferred Environment

Amazon Web Services (AWS), Continuous Delivery (CD), Continuous Integration (CI), Terraform, Google Cloud, Linux, Google Kubernetes Engine (GKE), Amazon EKS, GitHub Actions

The most amazing...

...projects I've done focused on building secure and reliable AWS infrastructures with Terraform.

Work Experience

Senior DevOps Engineer | Site Reliability Engineer

2016 - PRESENT
Freelance
  • Deployed, automated, managed, and maintained a cloud-based production system, using AWS, Google Cloud, Azure, and DigitalOcean.
  • Ensured availability, performance, security, and scalability of production systems, focusing primarily on Linux environments.
  • Troubleshot systems and resolved problems across various application domains and platforms. Tracked and fixed issues, using Jira and GitHub.
  • Migrated from a manually managed system to a fully automated platform which included creating CI/CD pipelines with Jenkins, GitHub Actions, Argo CD, Flux, Harness, and application of GitOps methodology.
  • Managed EKS, ECR, ECS, GKE, DigitalOcean Kubernetes, Docker, and Docker Compose deployments.
  • Deployed AWS infrastructure (EKS, EC2, RDS, CloudFront, Route53, OpenVPN, IAM roles/policies and VPC) with Terraform.
  • Deployed GKE clusters, Cloud SQL, LoadBalancer, and Compute Engine, and configured GitLab to push Docker images to the container registry.
  • Built Docker images and deployed them to AWS Fargate with GitHub Actions.
  • Created a Docker build pipeline with GitHub Actions, CircleCI, and Jenkins.
  • Applied AWS security best practices and CIS compliance requirements; configured AWS Security Hub, AWS Config, and VPC flow; and hardened GKE cluster security.
Technologies: Jenkins, Terragrunt, Packer, Amazon Web Services (AWS), GitHub, System Administration, Cloud Security, Docker, Continuous Delivery (CD), Continuous Integration (CI), Linux, AWS Fargate, Kubernetes, Amazon EKS, Terraform, DevOps, Google Cloud Platform (GCP), AWS DevOps, AWS Certified Solution Architect, Ubuntu Server, GitHub Actions, AWS Transfer for SFTP, Postfix, IT Security, NGINX, Zabbix, Google Kubernetes Engine (GKE), Docker Compose, AWS ELB, AWS CloudTrail, Docker Hub, Amazon Elastic Container Service (Amazon ECS), Shell, Gruntwork, CircleCI, AWS IAM, Amazon Virtual Private Cloud (VPC), Google Cloud SQL, Amazon Elastic Container Registry (ECR), Containers, CI/CD Pipelines, Linux Server Administration, Site Reliability Engineering (SRE), Argo CD, HAProxy, SecOps, Nagios, Datadog, Jenkins Pipeline, Harness CI/CD, DigitalOcean, Amazon EC2, Amazon CloudWatch, Amazon Simple Email Service (SES), MongoDB Atlas, Flux, Ubuntu, Git, Redis, MongoDB, Bash Script, Jira, Ansible, AWS Elastic Beanstalk, AWS CodePipeline, AWS CloudFormation, OpenVPN, Bitbucket, Cloudflare, GitOps, DevSecOps, GitLab CI/CD, VPN, Identity & Access Management (IAM), Python, Helm, Continuous Development (CD), Azure, Bash, Containerization, Amazon RDS, CentOS, SendGrid, RHEL, Microservices, Site Reliability, Leadership, Continuous Deployment, AWS Elastic File System, Relational Database Services (RDS), Redis Cache, AWS Certified DevOps Engineer, SSL Certificates, SSL Configurations, Transport Layer Security (TLS), AWS Cloud Architecture, Apache Kafka, Monitoring, AWS Certified Developer, Networking, Elasticsearch, Kibana, Grafana, Amazon EFS, SOC 2, Cloud Services, Kustomize, Red Hat OpenShift, Amazon DynamoDB, Prometheus, Serverless Architecture, Cloud Migration, AWS Lambda, DomainKeys Identified Mail (DKIM), SPF, Domain DNS Setup, Spam Filtering, Email, Cloud, AWS NLB, SQL, Amazon CloudFront CDN, Amazon Aurora, AWS NAT Gateway, Confluence, Karpenter, Celery, Django, Amazon EBS, Keycloak, HIPAA Compliance, Cloud Infrastructure, Cost Reduction & Optimization, Observability Tools, Web Security

Technical Team Lead and DevOps

2010 - 2016
Vision R&D
  • Established the technical vision and provided leadership to department heads.
  • Built the development platform and managed the project, using Jira, Confluence, and GitLab.
  • Managed the software development and quality assurance teams.
  • Identified and integrated new technologies to drive the business strategy and enhance client relationships.
Technologies: Security, System Administration, GitLab, Jira, Python, Git, Ubuntu, Red Hat Linux, Linux, MySQL, Postfix, IT Security, NGINX, AWS ELB, Shell Scripting, Linux Server Administration, Site Reliability Engineering (SRE), HAProxy, Nagios, Amazon Simple Email Service (SES), DevOps, Redis, Docker, Amazon EC2, MongoDB, Bash Script, Ubuntu Server, DigitalOcean, Google Kubernetes Engine (GKE), Cloud Security, OpenVPN, Bitbucket, Cloudflare, VPN, Bash, Containerization, CentOS, SendGrid, RHEL, Microservices, Site Reliability, Leadership, Continuous Deployment, Redis Cache, SSL Certificates, SSL Configurations, Transport Layer Security (TLS), Monitoring, Networking, Elasticsearch, Amazon EFS, SOC 2, Cloud Services, DomainKeys Identified Mail (DKIM), SPF, Domain DNS Setup, Spam Filtering, Email, Cloud, SQL, Mail Servers, Confluence, GitHub Actions, Cloud Infrastructure, Observability Tools, Web Security

Linux/Unix System Administrator | Site Reliability Engineer

2007 - 2010
Esys
  • Designed and managed a Linux (Red Hat, CentOS, and Ubuntu) and Unix infrastructure.
  • Maintained security and mitigated threats as new ones were identified.
  • Improved infrastructure services, performance, and reliability.
  • Became a Master Affiliate of The Linux Professional Institute (LPI), managed the company's training partner relationship with the institute, and grew the Linux and FOSS communities—all in Turkey.
  • Installed and maintained web, DNS, SMTP Server, and FTP on Linux.
  • Assisted with shell scripting for a system and application used to automate server tasks.
  • Created and maintained a secure and reliable Linux environment. Managed daily activities, including user support and system administration tasks.
Technologies: Security, System Administration, DNS, SMTP, Red Hat Linux, Linux, LPIC-1, SSH, Ubuntu Linux, Git, Ubuntu Server, IT Security, NGINX, Zabbix, Linux Server Administration, Site Reliability Engineering (SRE), Nagios, Amazon Simple Email Service (SES), Ubuntu, Redis, MongoDB, Bash Script, Qmail, OpenVPN, VPN, Bash, CentOS, SendGrid, RHEL, Site Reliability, Leadership, SSL Certificates, SSL Configurations, Transport Layer Security (TLS), Monitoring, Networking, Elasticsearch, DomainKeys Identified Mail (DKIM), SPF, Domain DNS Setup, Spam Filtering, Email, SQL, Mail Servers, Web Security

International DSL TAC Engineer

2003 - 2007
Alcatel Lucent
  • Managed the Unix servers for AWS products deployed for telecom operators.
  • Provided Unix and Linux support remotely or on-site in the EMEA region.
  • Matured into a successful and valued member of the Unix/DSL support team in the EMEA region.
Technologies: Linux, Networks, Unix, Solaris, NGINX, Site Reliability Engineering (SRE), Bash Script, Networking

Software Developer

2002 - 2003
Oyak Teknoloji
  • Developed host switch servers for debit and credit card systems in C++.
  • Built a banking software solution based on internal customer requirements.
  • Increased the performance of the process, which increased customer satisfaction, gained loyal customers, and maximized profitability.
Technologies: Unix, Qmail

Unix/Linux Systems Administrator and Developer

2000 - 2002
RT.NET
  • Participated in designing, implementing, securing, and maintaining Linux and the Solaris ISP for its test, development, and production environment.
  • Provided Linux, Solaris, and infrastructure support for internal and external clients.
  • Created and modified scripts and applications to perform tasks.
  • Improved the stability, security, efficiency, and scalability of the environment.
Technologies: System Administration, PostgreSQL, MySQL, Shell Scripting, Shell, Postfix, Qmail, DNS, FreeBSD, Linux, Solaris, Ubuntu Linux, Bash Script, CentOS

CIS Compliant AWS Infrastructure

I redesigned and built an AWS infrastructure by using AWS Reference Architecture and best practices with Terraform modules. The AWS components included EKS, ECR, S3, Config, Security Hub, IAM, GuardDuty, VPC Flow, RDS, and ELB.

Migration from Docker Compose to AWS EKS Cluster

I was a Devops engineer in this project and the apps were running on a single EC2 instance with docker-compose.

Tasks accomplished:

Migrated all docker-compose files to k8s manifests.
Deployed AWS EKS cluster with the following components:
AWS Load Balancer Controller
Sealed Secret to keep secrets encrypted on git repository.
External DNS to manage route 53 records automatically
Argo-CD to implement GitOps methodology
IAM assume roles to access EKS cluster

Everything was deployed with Terraform.

Implement IaC Scanner for Terraform Codes for AWS Resources

I was a DevSecOps engineer in this project and I used Checkov to scan Terraform codes on each git push and Harness deployment.

Checkov is a static code analysis tool for infrastructure-as-code.

It scans cloud infrastructure provisioned using Terraform, Terraform plan, Cloudformation, AWS SAM, Kubernetes, Helm charts,Kustomize, Dockerfile, Serverless, Bicep, or ARM Templates and detects security and compliance misconfigurations using graph-based scanning.

I implemented Terraform scanning in GitHub Actions on every push. Also created scripts to use in the Harness pipeline to check Terraform code security before deploying apps to AWS. I also contributed to the Checkov open source project by submitting code fix PR, docs, and feature requests.

Languages

Bash Script, Bash, SQL, Python

Frameworks

SPF, Flux, Django

Libraries/APIs

Terragrunt, Jenkins Pipeline

Tools

Git, Google Kubernetes Engine (GKE), Postfix, Docker Compose, GitHub, OpenVPN, Zabbix, AWS ELB, Terraform, AWS Fargate, Bitbucket, Amazon CloudWatch, AWS CloudTrail, Amazon Elastic Container Service (Amazon ECS), NGINX, MongoDB Atlas, Packer, Amazon Simple Email Service (SES), Shell, Amazon EKS, CircleCI, Jenkins, GitLab, Docker Hub, AWS IAM, Amazon Virtual Private Cloud (VPC), Amazon Elastic Container Registry (ECR), GitLab CI/CD, Helm, SendGrid, Nagios, Amazon CloudFront CDN, Confluence, Amazon EBS, Grafana, AWS CloudFormation, Jira, Ansible, VPN, Kibana, Keycloak, Celery

Paradigms

DevOps, Continuous Integration (CI), Continuous Delivery (CD), DevSecOps, Continuous Development (CD), Microservices, Continuous Deployment, Serverless Architecture, HIPAA Compliance

Platforms

Linux, Kubernetes, Docker, DigitalOcean, FreeBSD, Ubuntu Linux, Amazon Web Services (AWS), Amazon EC2, Google Cloud Platform (GCP), Red Hat Linux, Ubuntu, Unix, CentOS, AWS NLB, AWS Elastic Beanstalk, Red Hat OpenShift, Azure, AWS Lambda, Solaris, Apache Kafka

Storage

Google Cloud, MySQL, Amazon S3 (AWS S3), Redis, AWS Elastic File System, Redis Cache, Amazon EFS, Amazon Aurora, PostgreSQL, MongoDB, Google Cloud SQL, Elasticsearch, Amazon DynamoDB, Datadog

Other

System Administration, Security, AWS Certified Solution Architect, LPIC-1, GitOps, Qmail, Shell Scripting, GitHub Actions, AWS DevOps, AWS Transfer for SFTP, SSH, Ubuntu Server, Cloud Security, Systems Monitoring, Cloudflare, Gruntwork, IT Security, Containers, CI/CD Pipelines, Linux Server Administration, Site Reliability Engineering (SRE), Argo CD, Infrastructure as Code (IaC), SecOps, DevOps Engineer, Identity & Access Management (IAM), Containerization, Amazon RDS, RHEL, Site Reliability, Leadership, Relational Database Services (RDS), AWS Certified DevOps Engineer, SSL Certificates, SSL Configurations, Transport Layer Security (TLS), AWS Cloud Architecture, Monitoring, AWS Certified Developer, Networking, SOC 2, Cloud Services, Kustomize, ECS, Cloud Migration, DomainKeys Identified Mail (DKIM), Domain DNS Setup, Spam Filtering, Email, Cloud, Mail Servers, AWS NAT Gateway, Cloud Infrastructure, Cost Reduction & Optimization, Observability Tools, Web Security, Prometheus, AWS CodePipeline, HAProxy, Load Balancers, SMTP, DNS, Networks, Computer Science, Harness CI/CD, Checkov, Karpenter

2012 - 2014

MBA in Business Administration

Istanbul Kemerburgaz University - Istanbul, Turkey

1997 - 2003

Bachelor's Degree in Computer Science

Istanbul Technical University - Istanbul, Turkey

JUNE 2022 - JUNE 2025

Certified Kubernetes Administrator (CKA)

Cloud Native Computing Foundation

FEBRUARY 2022 - FEBRUARY 2025

Certified Kubernetes Application Developer Certification (CKAD)

Cloud Native Computing Foundation

JANUARY 2018 - JANUARY 2020

AWS Certified Developer - Associate

AWS

JULY 2017 - JULY 2019

AWS Certified Solutions Architect - Associate

AWS

JULY 2011 - JULY 2016

The Linux Professional Institute — LPIC-1

The Linux Professional Institute

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