Philip J. Hollenback

philiph@pobox.com
San Francisco
www.linkedin.com/in/philiph

Overview

Staff Software Engineer with deep experience across SRE, security operations, and infrastructure software. Recent work centered on secure infrastructure and access control in Python - certificate-based host access, LDAP, SSO, and the reliability of the platforms behind them. I look for difficult cross-team infrastructure problems that need a clear owner.

Experience

LinkedIn, Sunnyvale, CA

Staff Software Engineer - August 2023 to May 2026

Technical lead on a 6-person infosec infrastructure team building software services around identity and authentication standards (LDAP, SSO).

• Led migration of a clustered Java LDAP service from Windows to Linux. Brought the service into LinkedIn’s standard deploy/monitoring stack, unblocked IPv6-only downstream consumers, and moved it from the business network into prod with tighter access controls.
• Rewrote LinkedIn’s internal Python LDAP client library; adopted by 200+ services. DNS TXT records carry both server discovery and per-service routing config, enabling per-service cluster targeting and whole-fabric failover. Multithreaded connection management lets long-running clients move between servers without restart.
• Drove an SSO integration program across the company: helped 500+ services migrate to SSO in six months, coordinating across 10+ partner engineering teams.
• Operated and extended an internal system for host access. This system used short-lived SSH certificates tied to user identity in place of standing credentials.

Staff Site Reliability Engineer - September 2019 to August 2023

Technical lead on an infrastructure tooling team. Designed and built an automated framework for certifying new Linux OS releases against the LinkedIn software stack.

• Certified OS releases destined for a 100,000+ host production fleet. Framework integrated 50+ test suites contributed by other engineering teams.
• Replaced a manual two-week certification cycle with an automated process completing in under one day. Implemented in Python.
• Certified 10 OS releases through the framework.

Oracle, San Francisco, CA

Senior Security Operations Engineer - November 2016 to August 2019

Technical lead in Security Operations for Oracle Cloud, focused on vulnerability management, identity hardening, and patch automation.

• Stood up Oracle Cloud’s first vulnerability scanning program (OpenVAS, several hundred core hosts) to support compliance efforts.
• Led Yubikey-based 2FA rollout to ~300 employees, eliminating non-2FA logins from the authentication infrastructure.
• Wrote a Fabric-based monthly patching system for the internal identity management fleet of 50 servers.
• Built Grafana dashboards for security operations metrics and ran biweekly operational excellence reviews.

Lookout, San Francisco, CA

Senior Production Engineer - July 2015 to November 2016

Release engineering team member at a mobile security company. Managed Jenkins, Gerrit, and Artifactory. Automated service deployments using NixOS on AWS.

• Built end-to-end automated deployment for Artifactory. The one-step deploy fully provisioned and configured all associated AWS components.

Goodreads, San Francisco, CA

Senior Systems Engineer - April 2014 to July 2015

Half of a two-person operations team at Goodreads, sharing on-call and incident response for a top-100 site. Built automation and monitoring in Bash, Ruby, and Perl.

• Automated MySQL database failover in Ruby. Replaced a manual 45-minute process with a 5-minute automated one.

Earlier roles on my LinkedIn profile.

Skills

Languages: Python, Go, Bash

Reliability: Site reliability engineering, on-call/incident response, post-mortems, SLO/SLI design, capacity planning

Observability: Grafana, metrics pipelines, dashboard design, alerting

Identity & Security: LDAP, SSO, OAuth, IAM, host access control, security operations, vulnerability management, 2FA rollouts

Infrastructure: Linux internals, AWS, containers, distributed systems, infrastructure automation, CI/CD (Jenkins, Gerrit, Artifactory), release engineering

Education

Bachelor of Science in Computer Science, The University of Montana. Emphasis in Artificial Intelligence. Minor in English Literature.