Principal Site Reliability Engineer

Harnham is an AI-driven advertising technology company providing customizable algorithmic media buying infrastructure. They are seeking a Principal Site Reliability Engineer to define and own the AWS event-driven platform design, build systems, and establish standards for operational capability over time.

Responsibilities:

• Define and own AWS event-driven platform design
• Build systems using EventBridge, Kafka/MSK, Kinesis, Lambda, Fargate, SQS/SNS, Step Functions
• Establish standards for idempotency, event schema governance, and traceability
• Help grow the SRE function and operational capability over time
• Operate/optimize multi-cluster production K8s
• Manage API server scaling, etc performance, RBAC, admission controllers
• Implement GitOps, progressive delivery, cluster level security, multi-tenant isolation
• Define Terraform module standards
• Build reusable infrastructure primitives
• Enforce GitHub guardrails and CI/CD safety
• Implement automated infra testing, policy validation, rollback safety
• Create containerized model-serving architecture (OCI images)
• Define security, isolation, telemetry, upgrade strategy, and runtime contracts
• Define SLIs, SLOs, error budgets
• Implement distributed tracing and golden signals
• Build incident response, on-call structure, escalation standards
• Ensure clear boundaries between infra, ML systems, and application teams
• SSO, provisioning, Terraform deployment
• Cluster policies + Unity Catalog governance

Requirements:

• 7–10+ years in SRE / Infrastructure / Platform Engineering
• Strong software/data engineering crossover
• AWS expert
• Databricks, Apache Spark, Snowflake experience
• Deep experience handling large-scale data (5–8+ TB batches every 4 hours)
• Experience building greenfield systems in fast-moving startups
• Ad tech or marketing tech background
• History of promotions / growth
• Has built systems from 0 to 1
• Broad technical exposure