Route 53 with ELB integration in AWS - Step-by-Step Execution

Process Flow - Route 53 with ELB integration

User DNS Request

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Route 53 Receives Request

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Route 53 Checks Record Type

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Is it Alias to ELB?

No→Return Other Record

Yes↓

Route 53 Resolves ELB DNS Name

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Return ELB DNS Name to User

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User Connects to ELB

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ELB Forwards Traffic to Targets

When a user requests a domain, Route 53 checks if the record is an alias to an ELB. If yes, it returns the ELB's DNS name, directing traffic to the load balancer.

Execution Sample

AWS

Create Route 53 record:
Type: A (Alias)
Alias Target: ELB DNS name

User queries domain
Route 53 returns ELB DNS name
User connects to ELB

This setup directs user traffic from a domain name to an ELB using Route 53 alias records.

Process Table

Step	Action	Input	Decision/Result	Output
1	User sends DNS query	example.com	Route 53 receives query	Query received
2	Route 53 checks record type	example.com record	Record is Alias to ELB	Proceed to resolve ELB
3	Route 53 resolves ELB DNS	ELB DNS name	ELB DNS resolved	ELB DNS name
4	Route 53 returns ELB DNS name	ELB DNS name	DNS name sent to user	User receives ELB DNS name
5	User connects to ELB	ELB DNS name	Connection established	Traffic forwarded to ELB targets
6	ELB forwards traffic	User request	Targets respond	User gets response

💡 Process ends after ELB forwards traffic to targets and user receives response.

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	Final
DNS Query	None	example.com	example.com	example.com	example.com
Record Type	Unknown	Alias to ELB	Alias to ELB	Alias to ELB	Alias to ELB
ELB DNS	None	None	elb-123456.us-east-1.elb.amazonaws.com	elb-123456.us-east-1.elb.amazonaws.com	elb-123456.us-east-1.elb.amazonaws.com
ELB IPs	None	None	None	None	None
User Connection	None	None	None	None	Connected to ELB

Key Moments - 3 Insights

Why does Route 53 return IP addresses instead of the ELB DNS name?

Route 53 does not return IP addresses for alias records to ELB; it returns the ELB DNS name. The user then resolves the ELB DNS name to IPs. This is shown in step 4 of the execution_table.

What happens if the Route 53 record is not an alias to ELB?

Route 53 returns the record as is (like a standard A or CNAME record), shown by the 'No' branch in the concept_flow after checking record type.

How does the user traffic reach the actual servers behind the ELB?

After the user connects to the ELB DNS name, the ELB forwards traffic to its registered targets, completing the flow in step 6 of the execution_table.

Visual Quiz - 3 Questions

Look at the execution_table, what is the output at step 3?

A Route 53 receives the DNS query

B ELB DNS name

C User connects to ELB

D Traffic forwarded to ELB targets

💡 Hint

Check the 'Output' column for step 3 in the execution_table.

At which step does the user receive the ELB DNS name?

A Step 4

B Step 2

C Step 5

D Step 6

💡 Hint

Look at the 'Output' column in the execution_table for when the ELB DNS name is sent to the user.

If the Route 53 record was not an alias to ELB, what would change in the execution flow?

A Route 53 would resolve ELB DNS anyway

B User would connect directly to ELB IPs

C Route 53 would return the record as is without resolving ELB

D ELB would forward traffic to Route 53

💡 Hint

Refer to the concept_flow where the decision checks if record is alias to ELB.

Concept Snapshot

Route 53 with ELB integration:
- Create an Alias A record in Route 53 pointing to ELB DNS
- Route 53 returns ELB DNS name to user DNS queries
- User traffic goes to ELB
- ELB forwards traffic to registered targets
- Alias records simplify DNS management for ELB

Full Transcript

When a user requests a domain name managed by Route 53, Route 53 checks the record type. If the record is an alias to an Elastic Load Balancer (ELB), Route 53 returns the ELB's DNS name. The user then resolves the ELB DNS name to IP addresses and connects to the ELB. The ELB then forwards the traffic to its registered backend targets. If the record is not an alias to ELB, Route 53 returns the record as is. This integration allows seamless routing of user traffic from a friendly domain name to the ELB, which balances load across servers.