Sean De Stefano

I’m a Site Reliability Engineer with 10+ years of systems administration and site reliability experience across hybrid on-prem and cloud environments. I focus on building resilient, observable infrastructure and automating the work that slows teams down.

I lead compliance-ready infrastructure, including CMMC Level 2 / NIST SP 800-171 readiness and SOC 2 work. I scope CUI environments, assess controls, and build the supporting foundation—like internal PKI and isolated network segments—so security requirements become operational realities.

I build reliability through monitoring, automation, and secure access. I implemented centralized monitoring and alerting with Prometheus, Grafana, and Alertmanager, and I automated SSL certificate issuance and renewal using Let’s Encrypt, Route 53 DNS validation, and Vault, with alerts for renewal failures.

My engineering spans identity and infrastructure migration (SSO with Authelia/LLDAP/OIDC and Azure AD integration) and cloud/on-prem modernization. I migrate services to AWS (EC2, Lambda, Route 53, ACM, OpenSearch), manage infrastructure as code with Terraform plus Packer-built VM images on Proxmox, run containers on Nomad and K3s, and use Ansible for automated patching with snapshot-based rollback.