Authentication basics in Elasticsearch - Step-by-Step Execution

Concept Flow - Authentication basics

Start: Client sends request

↓

Check for credentials

↓

Validate creds

↓

Credentials valid?

The flow shows how Elasticsearch checks client credentials to allow or reject access.

Execution Sample

Elasticsearch

GET /_search
Authorization: Basic dXNlcjpwYXNz

Client sends a search request with Basic Authentication header.

Execution Table

Step	Action	Evaluation	Result
1	Receive request	Request has Authorization header	Proceed to validate credentials
2	Decode header	Base64 decode 'dXNlcjpwYXNz'	Get 'user:pass'
3	Check user/pass	Compare with stored credentials	Credentials valid
4	Grant access	Allow search operation	Return search results
5	End	Request processed successfully	Done

💡 Request ends after credentials are validated and access is granted.

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
Authorization Header	None	Basic dXNlcjpwYXNz	Basic dXNlcjpwYXNz	Basic dXNlcjpwYXNz
Decoded Credentials	None	user:pass	user:pass	user:pass
Credentials Valid?	False	False	True	True
Access Granted?	False	False	True	True

Key Moments - 3 Insights

Why do we decode the Authorization header?

Because the header is Base64 encoded, decoding reveals the actual username and password to check (see execution_table step 2).

What happens if credentials are missing?

The request is rejected immediately without validation (see concept_flow branch 'No' after 'Check for credentials').

How does Elasticsearch know if credentials are valid?

It compares decoded credentials with stored user data (see execution_table step 3).

Visual Quiz - 3 Questions

Look at the execution_table, what is the decoded credential after step 2?

A dXNlcjpwYXNz

B user:pass

C Authorization

D Basic

💡 Hint

Check the 'Decoded Credentials' column after step 2 in variable_tracker.

At which step does Elasticsearch decide to grant access?

A Step 4

B Step 3

C Step 1

D Step 5

💡 Hint

Look at the 'Action' and 'Result' columns in execution_table for when access is allowed.

If the Authorization header was missing, what would happen according to concept_flow?

A Credentials are validated

B Access is granted

C Request is rejected

D Request is retried

💡 Hint

See the 'No' branch after 'Check for credentials' in concept_flow.

Concept Snapshot

Authentication basics in Elasticsearch:
- Client sends request with Authorization header
- Header is Base64 decoded to get user:pass
- Credentials are checked against stored users
- Access granted if valid, else request rejected
- Missing credentials cause immediate rejection

Full Transcript

This visual trace shows how Elasticsearch handles authentication. When a client sends a request, Elasticsearch first checks if the Authorization header is present. If missing, the request is rejected immediately. If present, the header is Base64 decoded to reveal the username and password. These credentials are then compared with stored user data. If they match, access is granted and the requested operation proceeds. Otherwise, the request is rejected. The variable tracker shows how the Authorization header and decoded credentials change through the steps. The execution table details each step's action and result, helping beginners understand the flow clearly.