Demo

Cole Brennan

Denver, CO

Staff Site Reliability Engineer

Professional Summary

Treats observability as a product with owners, SLOs, and a budget. Kubernetes is the substrate; the work is making a page name the failing dependency before the war room does.

At Highwater, cut MTTR from 47 minutes to 14 and dropped paging noise 58% across 9 clusters. Previously ran Summit's tracing mesh and Alpine's first on-call that did not page on every 5xx.

Skills

13 years:

Python

12 years:

AWS

11 years:

Observability

10 years:

Distributed Systems,

Go

9 years:

Kubernetes

8 years:

System Design

6 years:

Technical Leadership

Work Experience

Highwater Observability - Denver, CO

Staff Site Reliability Engineer — November 2020 to present

Replaced threshold alerts with error-budget burns and cut pages 58% while MTTR fell to 14 minutes Observability, Technical Leadership, Python
Unified traces across 9 EKS clusters and cut time-to-name-the-dependency from 18 minutes to 3 Kubernetes, Distributed Systems, AWS, Observability
Shipped a Go admission webhook that flattened time-series growth 71% and stopped surprise telemetry bills Go, System Design, Kubernetes

Summit Mesh Ops - Boulder, CO

Senior Site Reliability Engineer — February 2018 to October 2020

Defined a span contract six clients adopted and cut duplicate incident channels from 4 per outage to 1 Observability, Distributed Systems, Technical Leadership
Split noisy batch onto dedicated node pools and cut noisy-neighbor latency events 64% Kubernetes, AWS, System Design

Site Reliability Engineer — April 2016 to February 2018

Mailed weekly SLO budget-burn reports that cut unowned 5xx alerts 40% once owners were named Python, Observability
Moved Prometheus scrape onto private links and cut accidental public metric endpoints from 11 to 0 AWS, Go, Kubernetes

Featured Projects

High-cardinality time series budget admission webhook Go, Kubernetes, System Design

Reference admission controller that keeps high-cardinality labels out of the time-series store. Written after a single deploy doubled a client's Prometheus bill. A new unbounded label is a design review, not a surprise invoice.

Reusable SLO and paging contract template Observability, Technical Leadership, Python

A reusable SLO and paging contract: burn-rate alerts, ownership fields, and the rule that saturation without a user-facing burn does not wake anyone. Includes the weekly budget-burn mail that kept names on the dashboard accurate.

Education

University of Colorado Boulder

B.S. Computer Science — May 2013

Certifications

Certified Kubernetes Administrator

Cloud Native Computing Foundation — August 2019

Credential ID: CKA-COLE-0816

AWS Certified SysOps Administrator – Associate

Amazon Web Services — January 2021

Credential ID: SOA-COLE-0129