Mainul Hossain

Site Reliability Engineer @ Optimizely

mainul_pic.jpg

Platform Engineering Team

Optimizely Bangladesh

Dhaka, Bangladesh

Hello! I’m Mainul, a Site Reliability Engineer focused on building dependable, scalable systems and simplifying complex cloud operations.

Currently, I work at Optimizely on the Reliability/Platform Engineering team, helping to implement and maintain cloud-native SaaS solutions for fast, scalable, and resilient infrastructure.

Previously, I worked in the Strategic Support Solutions team within Technical Support Services, optimising customer Azure environments and developing automation to reduce operational toil.

I studied Computer Science at BRAC University. I work across Microsoft Azure and AWS, containerise with Docker and Kubernetes, and manage infrastructure as code. I primarily script in Python, with Bash and Ruby as needed.

Here are a few technologies I’ve been working with:

  • Python  ·  Bash  ·  PowerShell  ·  Ruby
  • Azure  ·  AWS  ·  Docker  ·  Kubernetes/AKS
  • Terraform  ·  Azure Policy & Defender for Cloud  ·  Datadog  ·  Prometheus  ·  Grafana
  • LLM / Prompt Engineering  ·  scikit-learn  ·  LightGBM  ·  Prophet

Where I've Worked

Site Reliability Engineer @ Optimizely

Reliability / Platform Engineering  ·  Jun 2025 – Present

  • Built an AI-powered infrastructure monitoring tool and Agent Prompt Optimization workflow forecasting Black Friday readiness, with automated PowerShell performance data collection cutting manual analysis time 30%.
  • Built a Terraform-managed Datadog Workflow that auto-restarts the Datadog agent on Elasticsearch via Azure RunCommand (VM/VMSS-aware, audited, on-call escalation), supporting a 99.99% SLA and cutting manual intervention 50%.
  • Led a tenant-wide Defender for Cloud/Advisor security remediation program: enabled EncryptionAtHost on Linux Elasticsearch VMs across 5 global regions via Octopus Deploy PowerShell runbooks, and rolled out automatic periodic update assessment across 200+ VMs.
  • Led a full AKS cluster upgrade (v1.32 to v1.33.x) across 48 clusters ahead of Azure's platform retirement deadline, resolving stuck node-upgrade failures via manual draining.
  • Audited 1,430 subscriptions via Azure Resource Graph to identify SSTP VPN Gateways ahead of retirement, confirming 7 gateways for migration; migrated Azure Function Apps from Linux Consumption to Flex Consumption ahead of the Sep 2028 deadline.
  • Refactored container registry authentication for two production services from hard-coded secrets to managed identity, removing a recurring downtime cause.
  • Automated Datadog health-report generation per DXP service with Cloudflare Zone integration; decommissioned 40+ unused Azure Function subnets and implemented Terraform-managed storage lifecycle policies for Event Hub data.
  • Supported on-call/support rotations resolving P1 incidents (Application Gateway, API gateways, Elasticsearch cluster health) and capacity planning reviews; implemented Azure automation for .NET Core proactive monitoring, cutting investigation time 70%.
  • Collaborated across SRE, Operations, and Engineering to define SLOs/SLIs and expand IaC and secure deployment practices across AWS and Azure.

Managed Services Engineer @ Optimizely

Strategic Support Solutions  ·  Mar 2024 – Jun 2025

  • Deployed containerized Python automation using Docker/Kubernetes for auditing and cost-optimization processes.
  • Implemented infrastructure-as-code practices for Azure service optimization, reducing operational costs by 25%.
  • Developed Python and Bash automation for API integrations, data extraction, and troubleshooting workflows.
  • Enhanced CI/CD pipelines using GitHub Actions for microservices deployment, reducing deployment time by 30%.
  • Built monitoring and alerting solutions using Azure KQL and Datadog for distributed system observability.
  • Administered Linux-based systems and managed AWS/Cloudflare CDN services for high-availability architectures.
  • Maintained incident management processes and provided L2/L3 support for production system outages.

Associate Managed Services Engineer @ Optimizely

Incident Management  ·  Sep 2022 – Mar 2024

  • Led incident response during high-volume traffic surges and major system outages, ensuring rapid detection and resolution.
  • Managed production deployments and database changes with zero-downtime deployment strategies.
  • Administered F5 load balancers and network security configurations for distributed systems.
  • Served as Microsoft Azure Administrator for the Optimizely DXP platform, maintaining 99.5% uptime across multiple regions.
  • Implemented standardized incident management procedures, improving escalation processes and documentation.

Information Technology Officer @ Univ. of Scholars

Information Technology  ·  Mar 2022 – Sep 2022

  • Designed and maintained Linux/Windows server infrastructure for university database and web systems.
  • Deployed Windows Server domain controllers and implemented organization-wide monitoring solutions.
  • Managed LAN/WAN network architecture and IP device configurations for campus connectivity.