kalilurrahman/kr-claudiator-skills/cloud-cost-allocation

Cloud Cost Allocation

Cost allocation makes cloud spending visible, attributable, and actionable. Without it, teams do not know what they are spending, nobody optimises, and the bill surprises everyone at month end.

Tagging Strategy

Every cloud resource must be tagged at creation time. Tags are enforced via AWS Service Control Policies, Azure Policy, or GCP Organization Constraints.

Required tags

• Environment: production, staging, dev
• Team: backend, platform, ml, data
• Service: orders-api, ml-training, analytics-pipeline
• CostCenter: CC-1234
• Owner: alice@company.com

Enforce in Terraform:

locals { required_tags = { Environment = var.environment Team = var.team Service = var.service_name CostCenter = var.cost_center Owner = var.owner_email ManagedBy = "terraform" } }

AWS SCP to deny resource creation without required tags:

{ "Effect": "Deny", "Action": ["ec2:RunInstances", "rds:CreateDBInstance", "s3:CreateBucket"], "Resource": "*", "Condition": { "Null": { "aws:RequestedTag/Team": "true", "aws:RequestedTag/Service": "true" } } }

Cost Allocation Report (Python + boto3)

import boto3 from datetime import datetime

def get_team_costs(start_date, end_date): ce = boto3.client("cost-explorer", region_name="us-east-1") response = ce.get_cost_and_usage( TimePeriod={"Start": start_date, "End": end_date}, Granularity="MONTHLY", GroupBy=[ {"Type": "TAG", "Key": "Team"}, {"Type": "TAG", "Key": "Service"}, ], Metrics=["UnblendedCost"], ) costs = {} for result in response["ResultsByTime"]: for group in result["Groups"]: team = group["Keys"][0].replace("Team$", "") service = group["Keys"][1].replace("Service$", "") amount = float(group["Metrics"]["UnblendedCost"]["Amount"]) costs.setdefault(team, {})[service] = amount return costs

Cost Anomaly Detection

AWS Cost Anomaly Detection monitors daily spend per service and alerts when a spike exceeds a threshold. Configure via Terraform:

resource "aws_ce_anomaly_subscription" "alerts" { name = "cost-anomaly-alerts" frequency = "DAILY" threshold_expression { dimension { key = "ANOMALY_TOTAL_IMPACT_PERCENTAGE" values = ["20"] match_options = ["GREATER_THAN_OR_EQUAL"] } } subscriber { address = "platform-team@company.com" type = "EMAIL" } }

Budget Alerts

Set team-level budgets with alerts at 80% and 100%:

resource "aws_budgets_budget" "team_budget" { name = "backend-team-monthly" budget_type = "COST" limit_amount = "5000" limit_unit = "USD" time_unit = "MONTHLY"

notification { comparison_operator = "GREATER_THAN" threshold = 80 notification_type = "ACTUAL" subscriber_email_addresses = ["backend-team@company.com"] } }

Anti-Patterns to Avoid

10 Rules

1. Tagging enforced by policy not convention - SCPs block untagged resource creation.
2. Every team has a monthly cost budget and owns it.
3. Cost anomaly detection fires within 24 hours of a spike.
4. Cost reported to teams weekly not just to finance monthly.
5. Untagged spend reported separately to drive tagging compliance.
6. FinOps review monthly: identify and action top 3 cost optimisations.
7. Spot/preemptible instances for batch workloads - 60-80% savings.
8. Reserved instances or savings plans for stable baseline workloads.
9. Right-size instances monthly - oversized instances are the biggest waste.
10. Cost is a product metric - teams own their cloud spend like their SLOs.