The resources scattered throughout your AWS infrastructure form a map of your org. They show how your organization plans and makes technical decisions. Let's walk through some scenarios and see what they imply about your org structure.
You have 57 RDS instances, each with a different combination of instance type, EBS volume type, and database engine. Technical decision-making is decentralized.
Your entire EC2 fleet is comprised of six instance types. Capacity planning is centrally-managed, as is cloud orchestration.
Half of your Elasticsearch clusters are AWS-managed; the other half run on self-managed EC2 instances. There is misalignment between two (or more) teams. Cost is not consistently considered when making architectural decisions, which means that engineering is misaligned with finance.
You buy reserved instances for EC2 but not ElastiCache. Missing payment options and offering classes on ElastiCache RIs prevent you from applying your EC2 RI purchasing rules. Your biggest ElastiCache spender does not discuss this with finance, indicating a missing escalation path.
You keep submitting service limit increases for VPC peering limits. Engineering teams think they are building isolated infrastructure, but changing requirements break these assumptions. There is not enough global coordination during medium-term planning cycles.
One of your workloads upgrades from c3s to c5ds the day they are released; another similar workload does not. Teams operate in silos. Technology news relevant to development propagates haphazardly.
You purchase hundreds of reserved instances every month. You have a team dedicated to globally-optimizing AWS costs.
Fixing the misalignments in these case studies requires increased communication.
Within engineering, 1:1s across team boundaries can be an effective way of socializing information. Working groups for teams that have similar workloads or infrastructure needs can align folks on consistent techniques.
The misalignments between engineering and finance in the case studies span department boundaries. To correct these, designate a single point of contact (person or team) from each department. The points are responsible for communicating each other's requirements across the department boundary. Having a single directly responsible individual (DRI) within a department makes it easy to determine accountability.
Core to the dysfunction in the above case studies is the tension between centralized and decentralized decision-making. I think the correct way to strike a balance is to identify the areas you care about and assign a single DRI for each. This allows you to centralize individual projects as well as avoid single points of failure.
If you want to change your story around Elasticsearch, cost optimization, and cross-team planning, assign a single person responsibility and imbue them with the authority to make changes. It helps if these DRIs align with team responsibilities so they may enlist additional resources if required.
We use this model at Stripe. The Search Infrastructure team is consolidating our Elasticsearch infrastructure, the Insight team drives our cost optimization strategy and reserved instance purchasing, and the TPM org drives org-wide planning. Each team has consistently improved how we execute on the area for which they are responsible because they are empowered to do so.