Public Code

• Linux-Home
  • This is a repo I have cultivated over the last ~15 years. The more I hone it the faster I can have a brand new RHEL machine up and running how I want it. At this point I think I'm down to less than 20 minutes.
  • Soon to come is an OSX-home.
• LaTeX Build Container
  • The PDF resume you see below is built with LaTeX, and I needed a way to easily build when I want. So I made a container that can do it for me.
• Tech Notes
  • These are notes that I keep for quick access to past things I have learned.
  • There are good nuggets in there:
    • SSH
      • I figured out a way to hijack an ssh connection, which I think has been patched since figuring this out.
    • Insert a layer into a built container
      • For some security testing I was doing, I wanted to figure out if I could insert a layer into a container surreptitiously. I figured out how to insert a layer, but it did change the final checksum.
      • There are reasons I can think of to want to do this but I've never found the right usecase.

Brock M. Renninger

Staff Engineer & Director of DevOps

Littleton, CO · brock@renninger.dev

Career Summary

• Engineering leader for 30+ DevOps engineers across multiple concurrent teams: performance reviews, career growth, escalation, and primary interface to executive leadership.
• Founded a 50+ person mentorship program; coach managers, tech leads, and junior engineers, and build psychologically safe teams.
• 20+ years of hands-on Linux infrastructure and platform engineering (Kubernetes, Terraform/OpenTofu, GitLab CI, Vault, AWS, Azure); still set technical direction and architecture daily.

Technical Skills

• AI: Claude Code, MCP, OpenAI
• CI/CD: git, GitHub Actions, GitLab CI
• Cloud & Virtualization: AWS, Azure, VMware
• Containers: Docker, Helm, Kubernetes (AKS, EKS, RKE2), Podman
• Infrastructure as Code: Ansible, OpenTofu, Terraform
• Languages: Bash, C, Go, Python
• Linux (20+ years): Debian, RHEL
• Security: Consul, HashiCorp Vault, image signing, policy-as-code, SBOM, vulnerability scanning

Professional Experience

SigmaDefense | Mar 2017 – Present

Staff Engineer & Director of DevOps (DevOps Practice Lead)

Promoted from DevOps Engineer to Sr DevOps Engineer / Project Architect & Tech Lead, then to Staff Engineer & Director of DevOps

• Lead 30+ DevOps engineers across multiple concurrent teams as their primary advocate, escalation point, and interface to the Director of Engineering; own annual performance reviews for all tech leads and their teams.
• Founded a structured mentorship program serving 50+ participants — curriculum, mentor/mentee matching, expectation-setting, and ongoing facilitation.
• Coach managers, tech leads, and junior engineers across the company, and cultivated a lasting safe space for engineers to surface frustrations, ask hard questions, and grow outside the management chain.
• Established and led recurring education sessions for senior customer leadership and executive stakeholders around a questions-first, no-ego culture, translating engineering realities into executive context and project-level expectations.
• Selected to architect and deliver high-profile projects requiring rapid turnaround or strong technical direction; direct build, test, and delivery strategy across multiple concurrent projects.
• Architect Kubernetes environments (AKS, EKS, RKE2) for 10+ projects across bare metal, virtual, and cloud infrastructure, provisioned with Terraform/OpenTofu on AWS, Azure, and VMware and kept consistent with Ansible.
• Designed secure hub-and-spoke architectures on bare metal, AWS, and Azure, using HashiCorp Vault and Consul for secrets and service discovery.
• Engineer GitLab CI/CD pipelines that automate each security step (vulnerability scanning, SBOM generation, secrets management, and policy-as-code checks), producing audit-ready evidence for security and compliance review.
• Maintain a secure software supply chain with signed, traceable container images deployed through Helm, so development continues while release snapshots await sign-off.
• Containerized services, automated manual processes, and refactored codebases to cut build times, in some cases from a week to an hour.
• Accelerated CI/CD tooling across teams through AI-assisted development (Claude Code and MCP), and administer Claude access for the company's developers.

ReadyTalk (acquired by PGi) | Jun 2016 – Feb 2017

Software Engineer III, Foxden.io

• Delivered Docker-based Jitsi video conferencing infrastructure spanning UI and server components.

Lockheed Martin | May 2005 – Jun 2016

Sr Software Engineer

• Led design and development of a security-certified data transfer appliance for moving data safely between networks of different trust levels, architected around three layers of trust: hardware, operating system, and data transfer.
• Developed a secure, multi-networked data transfer program in C using simultaneous wired and wireless technologies.
• Built, packaged, and maintained a custom Linux OS for a distributable VoIP/GSM telephony prototype using Asterisk.

Education

University of North Dakota — Bachelor of Science, Computer Science

Interests

• Artwork: pencil, pen, and watercolor.
• PCB design: building my own split keyboard.
• AI-assisted tinkering: building bespoke tools for problems that had perfectly good answers, none of which fit just right.