EKS Control Plane Logging Discipline

Control plane logs reveal cluster issues. The logs to enable, the cost trade-off, and what each catches.

Available logs

EKS control plane logging is the discipline of capturing the cluster's own operational data. The control plane (API server, scheduler, controllers, audit subsystem) produces logs that are invaluable for security investigation, debugging, and compliance. Without control plane logs, the team operates the cluster blind to internal behavior; with them, the cluster is fully observable.

What logs are available:

• API server: every API call.: Every kubectl command, every controller request, every webhook invocation produces an API server log entry. The volume is high; the value is high. The log answers "what was requested of the cluster?".
• Audit: who did what when.: The audit log records who made API calls, what they did, and what the result was. The data is structured and queryable; compliance reviews and security investigations rely on it.
• Required for compliance.: Most compliance regimes (SOC 2, PCI, HIPAA, FedRAMP) require audit logging. The audit log produces the evidence that the cluster's actions are tracked.
• Authenticator: auth failures.: Failed authentication attempts are recorded. The data catches bad-actor activity: brute-force attempts, expired credential usage, attempts to assume roles without permission. Patterns in the data feed security operations.
• Controller manager and Scheduler.: Lower-level cluster behavior. Why was this pod scheduled there? Why did this controller take action? When debugging cluster behavior, these logs are the source of truth.

Each log type serves different use cases. The team enables the ones that match their needs.

Cost trade-off

Control plane logs cost money. AWS charges for ingestion, storage, and query against the logs. The cost is real; the value is also real; the trade-off requires deliberate choice.

• Each log type adds cost.: Each log type the team enables produces volume that gets billed. Some types are inexpensive; some are expensive.
• API server is the most expensive at scale.: The API server logs every API call. At scale (hundreds of nodes, thousands of pods, many controllers), the volume is enormous. The cost dominates other log types.
• Production: enable all.: Production clusters justify the full logging cost. Security investigation and compliance both require the data; the cost is part of operating the cluster.
• Non-prod: API plus audit minimum.: Non-production clusters can run with reduced logging. API server and audit are usually enough for development purposes; the lower-level controller and scheduler logs can be disabled.
• Periodic re-evaluation.: The cost-benefit shifts as the cluster grows. The team reviews periodically: are all the log types still pulling their weight? Should some be reduced or eliminated?

The cost trade-off is per-cluster. Production usually warrants full logging; non-production can be selective.

Retention

The retention policy determines how long logs are kept. Recent logs are queried often; older logs are queried rarely. The retention policy matches access patterns.

• 30 days hot.: The most recent 30 days are in fast-access storage. Incident response, recent change investigation, recent compliance queries all use the hot retention.
• 1 year cold for compliance.: Older logs move to cold storage for 1 year (or longer for some compliance regimes). The cold retention is rarely accessed but legally required.
• Query patterns dictate retention.: Some teams need longer hot retention; some shorter. The team's typical investigation horizon determines the right size. A team that frequently investigates 60-day-old issues needs 60-day hot retention.
• Tune by usage.: The retention is reviewed annually. If 30 days is rarely insufficient, it stays; if the team often reaches for older data, retention extends. The cost of expanding hot retention is real but bounded.
• Lifecycle automated.: The transition from hot to cold is automated via lifecycle policies. The team configures once; the storage cost optimizes itself; the team does not manage individual log entries.

EKS control plane logging is one of those operational disciplines that pays off proportionally to the cluster's importance. Nova AI Ops integrates with EKS control plane logs, surfaces patterns relevant to security and compliance, and produces the queryable view that the platform team uses for investigation and audit.