Lesson 041 · AWS Learning Path

AWS 041: IAM identities and authentication

Anil Jalela · Published Aug 5, 2025 · 8 min read

The problem

A team uses IAM identities and authentication as a label or Console setting without proving the identity, scope, behavior, failure boundary, cost, or operational result. The configuration appears complete but the real requirement remains untested.

Final outcome

The learner will inspect, explain, test, and document IAM identities and authentication. The submission must connect the Console and CLI view to the same AWS control, state what the evidence proves, diagnose one likely failure, and make a requirement-based architecture decision.

Learning outcomes

You will be able to:

1. explain authentication comes before authorization;
2. explain a principal makes a request;
3. explain human and workload identities differ;
4. explain credentials are not permissions;
5. explain iam is global with regional dependencies;

1. distinguish successful configuration from successful workload behavior;
2. preserve redacted evidence and complete the stated cleanup or retention decision.

Mental model

requirement
   -> identity and permission
   -> account, Region, and resource scope
   -> configuration or request
   -> observable state
   -> workload result
   -> failure evidence
   -> cleanup or controlled retention

Never begin with a create button or a copied command. Start with the result that must be proven and the boundary that must remain protected.

Core facts

How to reason about it

Start every access design with four questions: who needs access, which actions are required, which resources are in scope, and under what conditions. Then decide how the identity authenticates and where the authorization policy belongs. This prevents the common mistake of solving a workforce federation problem by creating more IAM users.

An IAM ARN identifies an IAM resource, while an STS assumed-role ARN identifies one temporary role session. CloudTrail often records the role session, including its session name and source identity, so meaningful session naming and federation attributes improve accountability.

Use the following decision table as a starting point, then change the answer when the scenario changes.

Prerequisites, permissions, Region, and cost

Run this lesson as the approved non-root course identity. Begin with aws sts get-caller-identity, confirm the private account record, and set the fixed project Region before any regional query. IAM resources are global within an account, while STS endpoints and the services reached by an identity can be regional.

Use only the read or change actions required for this lesson. An AccessDenied result is evidence to analyse, not permission to switch to root or attach AdministratorAccess. Record the action, resource, principal type, request context, and smallest justified correction.

The listed cost tier is T0 - no resource creation. Free Tier eligibility and credits are account-specific. Before a mutating lab, identify every resource that can charge, estimate its duration, start a timer, and write the reverse cleanup order. A budget reports cost after billing data arrives and is not a real-time stop control.

AWS Management Console method

1. Open IAM and review the account summary for users, roles, identity providers, and security recommendations.
2. Open one role and separate its Trust relationships tab from its Permissions tab.
3. Open CloudTrail Event history and inspect userIdentity for a federated or assumed-role API request.

For every step record the service page, selected account and Region, exact object, visible state, and why that state matters. A Console label or green status is not enough unless it is tied to the final workload outcome.

AWS CLI or API evidence

Identify the effective caller before troubleshooting permissions.

aws sts get-caller-identity
aws configure list

The returned ARN distinguishes an IAM user from an assumed-role session. The configuration list shows where the selected profile, Region, and credential settings came from.

Before running the command, replace every placeholder, explain each option, and decide whether the operation is read-only or mutating. Capture the exit code immediately. Redact account IDs, ARNs, public addresses, request identifiers, and personal data before sharing.

The CLI and Console are clients of AWS APIs. Matching state across them increases confidence, but neither substitutes for data-plane or application verification.

Practical work

Create iam-identities-and-authentication-evidence.md. Record the problem, account and Region preflight, observed Console state, matching CLI result, every decision in the table, one intentional misconception, one failure diagnosis, and the retained-state or cleanup result.

The evidence package must include:

• non-root principal type, account verified privately, and Region;
• exact intended and observed state;
• one Console observation and the matching CLI or API result;
• one successful result and one denied, failed, or counterexample result;
• what each result does not prove;
• cost state and elapsed lab time;
• cleanup evidence or a named retained-state owner and next lesson.

Verification standard

Use three levels of proof:

1. Control plane: the object or policy exists with the intended configuration.
2. Data plane or behavior: the request, packet, session, storage path, or application does what the requirement states.
3. Operations: monitoring, failure diagnosis, cost, ownership, and cleanup are known.

A control-plane response can precede final readiness. Use waiters or state polling where supported, then test the actual behavior. If a request times out, do not assume it failed. Inspect state and use documented idempotency before retrying a mutation.

Troubleshooting method

Keep the original symptom and timestamp. State one hypothesis, make one reversible change, repeat the original test, and record rollback. Never open a management port to the world, expose credentials, disable TLS verification, format an unknown disk, or add broad permissions as a generic fix.

Architecture and certification decisions

Professional-level questions provide competing valid features. Identify the requirement that decides between them: human or workload identity, same-account or cross-account access, regional or zonal scope, stateful or stateless filtering, durable or ephemeral data, latency, RTO/RPO, cost, or operational ownership.

Explain why the selected option fits and why each plausible alternative fails one stated requirement. Do not rely on feature memorization or reproduce protected certification questions.

Knowledge check

1. A valid access key receives AccessDenied. Did authentication fail?

Expected direction: Not necessarily. AWS recognized the caller, but authorization did not produce an applicable allow or an explicit deny blocked the request.

1. Should a Lambda function store an IAM user key in an environment variable?

Expected direction: No. Assign an execution role and let the runtime obtain temporary credentials.

1. Is an IAM role a person?

Expected direction: No. It is an assumable identity with permissions and a trust policy. A person, service, or workload obtains a role session.

1. Why record source identity in federated sessions?

Expected direction: It preserves the original user identity across role activity and improves CloudTrail attribution.

Cost, cleanup, and retained state

No workload resource should remain unless this lesson explicitly creates and retains one for the next numbered lab.

Cleanup evidence includes the final state query, not only a successful delete response. Search related resources, other Regions used by the lab, retained storage, public IPv4 addresses, logging destinations, and service-managed dependencies. Schedule a later billing review because cost data can lag.

Completion gate

Pass when the practical artifact explains the real problem, matches Console and CLI evidence, answers every knowledge check, diagnoses one failure without broadening access, records cost, and proves cleanup or approved retention. The learner must defend one decision orally and name the requirement that would change it.

Official sources

• IAM identities
• AWS security credentials
• IAM best practices