GILBERTO ROSARIO
Senior Site Reliability Engineer
Middlefield,CT
Summary
IT professional with 15+ years of experience in hybrid cloud, distributed computing, and containerized environments. Skilled in site reliability engineering, Kubernetes, DevOps automation, and cloud platforms (AWS, Azure, GCP). Proven ability to modernize infrastructure, improve system reliability, and optimize performance through Infrastructure-as-Code, observability, and CI/CD pipelines. Certified in Kubernetes, AWS, GCP, and Terraform, with strong collaboration skills and a master’s-level foundation in Information Security and Computer Information Systems.
Overview
2026
2026
years of professional experience
1
1
Certification
Work History
Senior Site Reliability Engineer – Hybrid Cloud Engineering
Pitney Bowes
01.2025 - Current
- Assisted in modernization of tooling and automation of infrastructure with Ansible, Terraform, and CI/CD pipelines to fast-track service delivery, remove manual tasks and handoffs
- Built and maintained Python & Bash scripts for infrastructure and application automation, deployments, and system checks.
- Provided support for development and production systems to enhance reliability, scalability, and performance of systems with SRE best practices.
- Setup and maintained distributed monitoring with Grafana cloud via automation, logging and tracing to gain system-wide telemetry for faster root cause analysis and incident resolution.
- Collaborated with application and infrastructure teams for their adoption of infrastructure-as-code and observability.
- Performed incident investigations, analyzes and prevention by correlating metrics and logs to identify the root cause.
- Managed and provisioned open-source and cloud-native platforms with high availability and resilience to failures across hybrid cloud environments (AWS, Azure, and on-prem).
Senior Customer Reliability Engineer – Kubernetes & Cloud Support Engineer
Sysdig, Inc
01.2023 - 01.2025
- Partnered with customers to design and implement optimal infrastructure deployment strategies while addressing technical challenges.
- Worked closely with Solutions Engineering and SRE teams to provide expert guidance on Kubernetes platform best practices and implementation.
- Led in-depth technical troubleshooting sessions with both customers and internal teams to diagnose and resolve complex issues.
- Developed automation strategies and implemented process improvements to enhance cloud infrastructure reliability across AWS, GCP, and Azure.
- Collaborated with development teams to analyze, troubleshoot, and resolve advanced performance and reliability concerns.
- Logged, tracked, and documented bugs and feature requests based on field observations and reproducible scenarios.
- Provided mentorship and training to team members, focusing on containerization and PaaS technologies in both private and public cloud environments.
- Played a key role in shaping reliability frameworks, processes, and best practices to support customer deployments of cloud-based and on-prem PaaS solutions.
Senior Customer Reliability Engineer – Kubernetes & Cloud Support Engineer
Astronomer, Inc
01.2022 - 01.2023
- Worked directly with customers and prospects to develop solutions for optimally deploying their infrastructure and to resolve technical issues.
- Collaborated with Solution Engineering and SRE teams in providing Kubernetes platform subject matter expertise and consulting services.
- Conducted technical troubleshooting sessions with internal team members and customers.
- Drove improvements to processes and design enhancements for automation to continuously improve the hosted cloud environments (AWS, GCP, Azure).
- Worked with development teams to investigate sophisticated performance and reliability issues and help them to resolve them.
- Triaged and documented bugs and enhancement requests as seen in the field, and through reproduction
- Mentored other team members specifically in container technologies delivered via PaaS offerings in private and public cloud.
- Engaged in a key role in the formulation of reliability processes and procedures in support of customer implementations of Astronomer PaaS within their on-prem or hosted environments.
Principle IO Engineer – Principle Openshift/Kubernetes Admin/Engineer
UnitedHealthcare Group/Optum Technology
2018 - 01.2022
- Provided direction in the analysis, design and implementing of complex RedHat Openshift Container Platforms for multiple federal projects using compliance policies based on the Federal Information Security Management Act (FISMA) and the Federal Risk and Authorization Management Program (FEDRAMP).
- Provided direction in establishing security base guidelines for the Openshift platform based on NIST frameworks and guidelines.
- Built solid working relationships with internal users and architecture teams.
- Created fully automated using Ansible and Git CI to build and deploy infrastructure and processes for multiple projects
- Developed docker images to support Development and Testing Teams and their pipelines; distributed Jenkins and ElasticSearch, and Kibana (ELK & EFK) etc.
- Developed and maintained comprehensive monitoring dashboards using Splunk, Telegraf, InfluxDB, Grafana (TIG stack), Prometheus, allowing for real-time visualization of system health and performance metrics.
- Developed scripts for build, deployment, maintenance and related tasks using Jenkins, Docker, Python and Bash
- Lead daily team meetings using Agile strategies for software development lifecycle.
- Worked closely with Developers, Architects and operations to rollout and deploy pipeline components specific to the use of the Openshift Container Platforms.
- Investigated production problems, perform root-cause analysis and develop post problem analysis and resolution reporting.
- Collaborated with cross-functional teams to ensure project milestones were met consistently.
Senior Technical Architecture Analyst
UnitedHealthcare Group/Optum Technology
01.2014 - 01.2018
- Designed, oversaw, and implemented complex Adobe Experience Manager (AEM/CQ 5.6.1, 6.0. 6.1, 6.2, 6.3) solutions (author, publish and dispatcher) from scratch using DevOps technology including Chef, Openshift, Docker, Jenkins, XLDeploy, HP Automation, RapidDeploy, and HP Operations Orchestration (HPOO).
- Responsible for designing and implementing integration of LDAP, Layer7, Siteminder and Apache configurations such as SSL/TLS for web application projects.
- Worked on reviewing colleagues’ AEM Infrastructure code and designs within github and Jfrog Artifactory and provide feedback and recommendations.
- Consulting with and negotiating with web server and infrastructure administrators to support infrastructure changes, stability, monitoring, and performance. Including but not limited to; Apache Dispatcher configuration, load balancing (F5), server and application maintenance, back-ups, disaster recovery, etc.
- Working knowledge and understanding of the following: Apache Sling, Apache Felix, Apache and App server logs, OSGi, RESTful web services, Javascript, jQuery, AJAX, JSON, HTML, CSS, and familiarity with SOLR/Lucene.
- Worked with web applications on developing and implemented apache rewrites/redirects within Apache/Dispatcher vhost configurations.
Web Systems Engineer
AETNA
2012 - 01.2014
- Built web infrastructure environments for development, integration, QA, Stage and Production web application server environments, including WebSphere and Microsoft IIS to support application deployment.
- Performed web infrastructure software installs and upgrades.
- Monitored overall capacity / performance of application and web server environment and perform necessary diagnostic and tuning to ensure compliant application servers as well as Microsoft IIS servers. Tune web infrastructure components (Java Virtual Machine attributes) for optimal performance for both system and application goals.
- Provided input, planning and support for disaster recovery for the web infrastructure tier.
- Supported stress testing and monitoring of applications deployed in the web infrastructure. Consult as necessary to assist in identifying performance and behavior issues with web applications and their impact to the application server behavior.
- Worked closely with application developers and architects on application system design and user interface needs and objectives.
- Participate in all phases of development and implementation as well as provide support on product specific technical questions and reviews of business requirements.
- Diagnosed, isolated and debugged software problems and perform problem resolution. Work closely with software vendors to troubleshoot, diagnose and resolve software issues within products. Capture necessary diagnostic information (i.e. traces, dumps) to provide to vendor.
- Provided 7x24 technical support for web infrastructure tier, including both software product and application issues.
Systems Performance Engineer
AETNA
01.2010 - 01.2012
- Identified system performance, and availability related issues impacting the organization.
- Problem resolution, improvement resource consumption, provide design modifications and implement operational support. Tune systems resources and recommend modifications to resolve performance and availability issues and improve resource consumption.
- Ensure that the infrastructure environment is sized and positioned with the appropriate hardware (mainframe and midrange processors, storage devices and other supporting equipment) to meet the business demand.
- Provide 7x24 problem resolution support using all of the available diagnostic tools including interacting with the user, the vendor and other technical areas.
- Recommended technical solutions to meet performance and fault tolerance requirements for distributed systems.
- Consult with customers regarding product usage, answers product specific technical questions and reviews business requirements.
Senior Technical Production Specialist
AETNA
01.2005 - 01.2010
- Utilized Mainframe/Midrange/Online scheduling processes to schedule batch jobs for complex business applications within assigned portfolio.
- Maintained single portfolio of complex applications with moderate to high business impact, or multiple portfolios with low to moderate complexity and business criticality.
- Exercised extensive knowledge and proactively manage business applications, environments, technology, and associated processes for assigned portfolio.
- Maintained awareness of environmental/technological enhancements. Effectively market potential improvements to business, application development, project management and IT Infrastructure organizations.
- Coordinated resources for upgrades/releases of business applications and or IT Infrastructure implementations relative to assigned portfolio.
- Proactively monitored and analyzed system events to mitigate risk scenarios and ensure stability of applications.
- Provided application/infrastructure support 24x7.
- Respond to daily operational issues.
- Maintained significant knowledge of Problem Management tools and assisted in resolution of day to day incidents involving business applications and IT infrastructure.
Education
Masters of Science - Information Security & Assurance
WESTERN GOVERNORS UNIVERSITY
Millcreek, UT01.2013
Masters of Science - Computer Information Systems
QUINNIPIAC UNIVERSITY
Hamden, CT05.2009
Bachelor of Science - Management Information Systems
CENTRAL CONNECTICUT STATE UNIVERSITY
New Britain, CT05.2004
Skills
- Security & Networking: SSL/TLS, HTTPS, Digital Certificates, Wireshark, TCPView, Netmon, Nmap, Nessus
- Programming & Scripting: Python, SQL, Bash, Perl
- Operating Systems: Windows, UNIX, Linux (RHEL, Red Hat Enterprise Linux)
- Monitoring & Observability: IBM Tivoli, Splunk, Dynatrace, Sitescope, Grafana
- ITSM & Agile Tools: ServiceNow, Rally, Kanban, SCRUM/Agile
- DevOps & CI/CD: Jenkins, GitHub, GitLab, Gitea, XLDeploy, JFrog Artifactory, Chef, Ansible, Terraform
- Containers & Orchestration: Docker, Kubernetes, OpenShift
- Cloud Platforms: AWS, Azure, GCP
Certification
- Certified Kubernetes Administrator (CKA) (cert id: LF-nx0rabvn9a)
- Google Associate Cloud Engineer
- HashiCorp Certified: Terraform Associate (003)
- AWS Certified Solutions Architect – Associate
- Prometheus Certified Associate
- National Agency Clearance (NAC)
- EC-Council Certified Ethical Hacker - EC-Council Computer Hacking Forensic Investigator
- SEI CMMI Appraiser - Six-Sigma (API Yellow Belt Certification)
- Foundation Certification in Information Technology Service Management (ITIL)
Languages
Spanish
Native or Bilingual
English
Native or Bilingual
Timeline
Senior Site Reliability Engineer – Hybrid Cloud Engineering
Pitney Bowes
01.2025 - Current
Senior Customer Reliability Engineer – Kubernetes & Cloud Support Engineer
Sysdig, Inc
01.2023 - 01.2025
Senior Customer Reliability Engineer – Kubernetes & Cloud Support Engineer
Astronomer, Inc
01.2022 - 01.2023
Senior Technical Architecture Analyst
UnitedHealthcare Group/Optum Technology
01.2014 - 01.2018
Systems Performance Engineer
AETNA
01.2010 - 01.2012
Senior Technical Production Specialist
AETNA
01.2005 - 01.2010
Masters of Science - Computer Information Systems
QUINNIPIAC UNIVERSITY
Bachelor of Science - Management Information Systems
CENTRAL CONNECTICUT STATE UNIVERSITY
Principle IO Engineer – Principle Openshift/Kubernetes Admin/Engineer
UnitedHealthcare Group/Optum Technology
2018 - 01.2022
Web Systems Engineer
AETNA
2012 - 01.2014
Masters of Science - Information Security & Assurance
WESTERN GOVERNORS UNIVERSITY
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