Sinan Polat.

$ whoami → polat-consultancy

Sinan PolatLinux & Cloud Consultant

15+ years building, automating and operating Linux, OpenStack, Ceph and Kubernetes platforms across Dutch government and enterprise.

sinan@polatconsultancy.nlLinkedInRijswijk, Netherlands

01 / About

Hands-on, since 2009.

I'm a freelance Linux and Cloud consultant with 15+ years of hands-on experience managing, troubleshooting and migrating Linux-based systems at scale.

I design, deliver and operate OpenStack and Ceph environments, run Kubernetes (Talos, OpenShift) workloads, and automate everything I can with Ansible, Python and Terraform.

I work comfortably with networking gear from my ISP/hosting background, and communicate clearly with both technical teams and non-technical stakeholders.

02 / Services

What I do for clients.

Independent freelance engagements, typically embedded in platform or infrastructure teams.

Linux Platform Engineering

RHEL & Ubuntu at scale — golden images with Packer, IPA, Satellite, patching, hardening, third-line ops.

Cloud & Virtualization

OpenStack and Ceph design, delivery and upgrades. Red Hat Virtualization, AWX, VMware, NSX-T migrations.

Containers & Kubernetes

Production Kubernetes on Talos and OpenShift. Helm, Flux CD, Vault, container migration from VMs.

Automation & CI/CD

Ansible/AWX, Terraform/Terragrunt, Jenkins, Python. Repeatable deploys, monitoring with Prometheus/Grafana.

03 / Stack

Tools I reach for.

Pulled from the platforms I run today and have built in the past.

Operating systems
RHEL 5/6/7/8/9/10CentOSDebianUbuntuFreeBSD
Cloud & virtualization
Red Hat OpenStackRed Hat VirtualizationVMwareNSX-TAzureAWS
Containers
KubernetesTalosRed Hat OpenShiftDockerPodmanHelm
IaC & automation
AnsibleAWXTerraformTerragruntPackerPuppet
CI/CD
JenkinsGitLabBitBucketGitFlux CD
Observability
PrometheusThanosGrafanaZabbixSensuCheck MKElasticsearchKibanaFluentd
Storage & data
Red Hat Ceph StorageMySQL / MariaDBInfluxDBNFSLVM
Identity & tooling
(Free)IPARed Hat SatelliteHashiCorp VaultPKI
Networking
Juniper EXCisco ACIFortigateNginxApachePowerDNSBINDPostfix
Languages & methods
BashPythonJSONAgileKanban

04 / Certifications

Certified, repeatedly.

15 certifications and trainings across Red Hat, Kubernetes, AWS, LPI, Juniper and Cisco.

  • Jul 2025Certified Kubernetes Administrator (CKA)
  • Oct 2022Red Hat Certified Specialist in Containers and Kubernetes (EX180)
  • Dec 2019PCEP — Certified Entry-Level Python Programmer
  • Nov 2019Red Hat Certified Specialist in Ansible Automation (EX407)
  • Oct 2019AWS Certified Cloud Practitioner (CLF-C01)
  • Nov 2018Red Hat Certified Engineer (RHCE 7, EX300)
  • May 2018Juniper Junos Intermediate Routing
  • May 2018Juniper Junos MPLS Fundamentals
  • Feb 2018Red Hat Certified Specialist in Red Hat OpenStack (EX210)
  • Sep 2017Cisco Application Centric Infrastructure (ACI)
  • May 2017Red Hat Ansible Automation Foundations
  • Sep 2016Red Hat Certified System Administrator (RHCSA 7, EX200)
  • Jul 2015Linux Professional Institute Certified 201 (LPIC-2)
  • Oct 2010Linux Professional Institute Certified 102
  • Oct 2010Linux Professional Institute Certified 101

05 / Experience

Where I've built and operated.

A timeline of roles, mostly in Dutch government and enterprise infrastructure teams.

  1. Apr 2024 – present

    Platform Infra Engineer· Netherlands Forensic Institute (NFI)

    Maintain and optimize OpenStack, Ceph, Kubernetes (Talos) and Linux environments. Git, Jenkins, Ansible, Terraform and Python.

    LinuxUbuntuKubernetesTalosOpenStackCephAnsiblePythonGitBitBucketFlux CDTerraformTerragruntJenkinsPrometheusGrafanaHelmVault

  2. Apr 2024 – present · part-time

    Linux Specialist· De Connectie

    Designed and built RHEL golden images using Packer, developed automated provisioning workflows integrating VMware with Red Hat Satellite, and created reusable Ansible roles orchestrated through AWX.

    RHEL 8/9/10AWXVMwareGitLabRed Hat IPAAnsiblePackerSatellite

  3. Aug 2023 – Apr 2024

    Linux Specialist· Ministerie van Defensie

    Designed and deployed the Linux building block. Streamlined operations through extensive Ansible automation.

    RHEL 7/8AnsibleGitLabPythonDockerGrafanaKibanaElasticsearchNagios

  4. Jan 2022 – Aug 2023

    Senior Linux / DevOps Engineer· Politie

    Customers & Roles team: wrote and maintained Puppet roles/profiles and Ansible playbooks. Later in Shared Infra, owning the tooling used by all Linux teams.

    RHEL 6/7/8SatelliteIPAAnsiblePuppetVMwareGitLabPythonBashIcinga

  5. Mar 2021 – Feb 2023

    Senior DevOps Engineer· Doculayer

    Implemented CI/CD pipelines for deploying the Doculayer application to Kubernetes on Azure and OpenStack, automated deployment workflows using Jenkins, Ansible and Helm, and implemented monitoring solutions with Prometheus, Thanos, Grafana and EFK.

    AzureOpenStackKubernetesJenkinsHelmVaultPrometheusThanosEFKGrafana

  6. Apr 2020 – Mar 2021

    Senior Linux Engineer· Rijkswaterstaat

    3rd-line engineer in Linux Operations, responsible for ~3000 VMs (RHEL 5–8). Automated patching with Ansible/AWX. Monitoring via Zabbix.

    RHEL 5/6/7/8SatelliteIPAAWXAnsiblePuppetVMwareNSX-TZabbix

  7. Jul 2018 – Sep 2020

    Linux / Cloud Specialist & Lead Engineer· Hot Potatoes Managed Hosting

    Designed and delivered 2 OpenStack + 2 Ceph clusters. Upgraded 2 OpenStack clusters, decommissioned and migrated one. Migrated VM-based apps to containers on OpenShift, and KVM VMs to Red Hat Virtualization.

    RHOSP 10/12/13CephRHVOpenShiftSatelliteIPAAnsibleTerraformJenkinsJuniperCisco ACI

  8. Dec 2016 – Jun 2018

    Linux / Cloud Specialist· EBPI

    Delivered virtual servers and middleware. Wrote Ansible playbooks. Managed Red Hat OpenStack, Satellite, IPA, RHV and Gluster.

    RHEL 6/7UbuntuOpenStackCephSatelliteIPARHVAnsibleCheck MKGrafana

  9. Mar 2009 – Nov 2016

    (Senior) Technical Linux Engineer· Leaseweb

    Team lead for 5 Linux support engineers. 2nd- and 3rd-line Linux support. Provisioned physical and virtual servers; managed Juniper switching.

    CentOSDebianUbuntuFreeBSDPleskcPanelDellHP ProliantJuniper

  10. Sep 2007 – Feb 2009

    FrontOffice ICT· Grafisch Lyceum Rotterdam

    ICT support for teachers. Installed and maintained Windows and macOS workstations and lab hardware.

    WindowsmacOSDellHPiMac

06 / Security research

Responsible disclosure.

Findings reported through coordinated disclosure programs and open-source security advisories.

Low

CVE-2026-58039

Permission Model bypass: process reports write outside the allowlist

Node.js

Reported that process.report could write and overwrite files outside the --allow-fs-write paths, bypassing the Permission Model boundary. Fixed in the July 2026 security releases for 22.x, 24.x and 26.x.

Node.js security release
Moderate

CVE-2026-55836

Path traversal / arbitrary server-file read in Open Zaak Documenten API

Open Zaak

Reported a path-traversal vulnerability in the Documenten API's document import (bestandspad), allowing arbitrary server-file reads. Patched in 1.27.2, 1.28.2 and 1.29.0.

GHSA-x5cj-23hr-5r54
Acknowledged

CVD

Coordinated Vulnerability Disclosure — Dutch government

Rijksoverheid

Identified and responsibly disclosed a security vulnerability in a Dutch government system under the CVD program, resulting in official acknowledgment.

07 / Contact

Let's talk.

Available for freelance Linux, cloud and platform engagements in the Netherlands.

Email

sinan@polatconsultancy.nl

Phone

06 818 54 997

LinkedIn

linkedin.com/in/sinanpolat

Based in

Rijswijk, NL

Polat Consultancy

DutchNative
EnglishGood — conversation & reading
TurkishGood — conversation & reading