VPC endpoints for private access in DynamoDB - Step-by-Step Execution

Concept Flow - VPC endpoints for private access

Start: Client in VPC

↓

Request DynamoDB Access

↓

Check VPC Endpoint Exists?

No→Request goes to Internet Gateway

Yes↓

Route Request via VPC Endpoint

↓

Access DynamoDB Privately

↓

Response Sent Back Privately

↓

End

This flow shows how a client inside a VPC accesses DynamoDB privately using a VPC endpoint, avoiding the public internet.

Execution Sample

DynamoDB

aws ec2 create-vpc-endpoint \
  --vpc-id vpc-123abc \
  --service-name com.amazonaws.us-east-1.dynamodb \
  --route-table-ids rtb-456def

This command creates a VPC endpoint for DynamoDB in a specified VPC and associates it with route tables.

Execution Table

Step	Action	Condition/Check	Result	Next Step
1	Client sends request to DynamoDB	Client is inside VPC	Request initiated	Check VPC endpoint existence
2	Check if VPC endpoint exists	VPC endpoint exists	Yes	Route request via VPC endpoint
3	Route request	Using VPC endpoint	Request routed privately	Access DynamoDB service
4	DynamoDB processes request	Request received via endpoint	Data accessed securely	Send response back
5	Response sent	Via VPC endpoint	Response received by client privately	End
6	If no VPC endpoint	Request goes to internet	Access denied or public route	End

💡 Execution stops after response is sent back privately or if no VPC endpoint exists, request goes via internet.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 5
Request Route	None	VPC Endpoint Exists	Routed via VPC Endpoint	Response received privately
Access Method	None	Private access enabled	Private access ongoing	Private access complete

Key Moments - 2 Insights

Why does the request not go through the internet when a VPC endpoint exists?

Because the VPC endpoint creates a private connection inside the AWS network, routing requests directly to DynamoDB without using the public internet, as shown in execution_table step 3.

What happens if the VPC endpoint is not created or associated properly?

The request will try to go through the internet gateway, which may be blocked or less secure, as shown in execution_table step 6.

Visual Quiz - 3 Questions

Look at the execution_table, at which step is the request routed privately via the VPC endpoint?

A Step 2

B Step 3

C Step 4

D Step 6

💡 Hint

Check the 'Result' column in execution_table row for Step 3.

According to variable_tracker, what is the 'Request Route' after Step 3?

A None

B Internet Gateway

C Routed via VPC Endpoint

D Blocked

💡 Hint

Look at the 'Request Route' row under 'After Step 3' in variable_tracker.

If the VPC endpoint does not exist, what is the likely outcome according to the execution_table?

A Request routed privately

B Access denied or public route

C Request sent to another AWS service

D Request automatically creates endpoint

💡 Hint

See the 'Condition/Check' and 'Result' columns in execution_table step 6.

Concept Snapshot

VPC endpoints allow private access to DynamoDB from inside a VPC.
They route requests within AWS network, avoiding the internet.
Create endpoints with AWS CLI or console, associating with route tables.
Requests use endpoint if it exists; otherwise, they go public.
This improves security and reduces latency.

Full Transcript

This visual execution shows how a client inside a VPC accesses DynamoDB privately using a VPC endpoint. The client sends a request, which checks if a VPC endpoint exists. If yes, the request routes privately through the endpoint to DynamoDB, and the response returns the same way. If no endpoint exists, the request tries to go through the internet, which may be blocked or less secure. Variables like 'Request Route' and 'Access Method' track the private routing state. Key moments clarify why private routing happens and what occurs if the endpoint is missing. The quiz tests understanding of routing steps and outcomes. Overall, VPC endpoints secure DynamoDB access inside AWS networks.

Practice

1. What is the main benefit of using a VPC endpoint for DynamoDB access?

easy

A. It allows private access to DynamoDB without using the internet.

B. It increases the internet bandwidth for DynamoDB queries.

C. It automatically backs up DynamoDB tables.

D. It enables cross-region replication of DynamoDB data.

Solution

1. Step 1: Understand VPC endpoint purpose

   A VPC endpoint lets you connect to AWS services privately inside your cloud network without internet traffic.

2. Step 2: Identify benefit for DynamoDB

   Using a VPC endpoint for DynamoDB means your data traffic stays inside AWS, improving security and privacy.

3. Final Answer:

   It allows private access to DynamoDB without using the internet. -> Option A

4. Quick Check:

   Private access = VPC endpoint benefit [OK]

Hint: VPC endpoints keep traffic inside AWS, no internet needed [OK]

Common Mistakes:

• Confusing VPC endpoints with internet bandwidth
• Thinking VPC endpoints backup data
• Assuming VPC endpoints replicate data across regions

2. Which AWS CLI command is used to create a VPC endpoint for DynamoDB?

easy

A. aws s3 create-vpc-endpoint --service-name com.amazonaws.region.s3

B. aws dynamodb create-endpoint --vpc-id vpc-123456

C. aws ec2 create-vpc-endpoint --service-name com.amazonaws.region.dynamodb

D. aws ec2 create-vpc --service-name dynamodb

Solution

1. Step 1: Identify correct AWS CLI service for VPC endpoints

   VPC endpoints are managed via the EC2 service commands, not DynamoDB or S3 commands.

2. Step 2: Match correct syntax for DynamoDB endpoint

   The command uses 'aws ec2 create-vpc-endpoint' with the service name for DynamoDB in the region.

3. Final Answer:

   aws ec2 create-vpc-endpoint --service-name com.amazonaws.region.dynamodb -> Option C

4. Quick Check:

   EC2 CLI + DynamoDB service name = create VPC endpoint [OK]

Hint: VPC endpoints use EC2 CLI, not DynamoDB CLI [OK]

Common Mistakes:

• Using dynamodb CLI instead of ec2 CLI
• Confusing S3 service name with DynamoDB
• Trying to create VPC instead of VPC endpoint

3. Given this AWS CLI command, what will it do?

aws ec2 create-vpc-endpoint --vpc-id vpc-abc123 --service-name com.amazonaws.us-east-1.dynamodb --subnet-ids subnet-1a2b3c --security-group-ids sg-123abc

medium

A. Creates a new VPC with DynamoDB access enabled.

B. Creates a VPC endpoint for DynamoDB in the specified VPC with subnet and security group.

C. Deletes the specified subnet and security group.

D. Creates a DynamoDB table in the specified subnet.

Solution

1. Step 1: Analyze the command components

   The command uses 'create-vpc-endpoint' with a VPC ID, service name for DynamoDB, subnet IDs, and security group IDs.

2. Step 2: Understand the effect of the command

   This creates a VPC endpoint inside the given VPC, allowing private DynamoDB access through specified subnets and security groups.

3. Final Answer:

   Creates a VPC endpoint for DynamoDB in the specified VPC with subnet and security group. -> Option B

4. Quick Check:

   Create VPC endpoint + DynamoDB service = private access setup [OK]

Hint: Look for 'create-vpc-endpoint' and DynamoDB service name [OK]

Common Mistakes:

• Thinking it creates a new VPC
• Confusing creation with deletion
• Assuming it creates DynamoDB tables

4. You tried to create a VPC endpoint for DynamoDB but got an error: "InvalidSubnetID.NotFound". What is the most likely cause?

medium

A. The security group ID is missing from the command.

B. The DynamoDB table name is incorrect.

C. Your VPC does not have an internet gateway attached.

D. The subnet ID provided does not exist in your AWS account or region.

Solution

1. Step 1: Understand the error message

   "InvalidSubnetID.NotFound" means the subnet ID given is not found or invalid in your AWS environment.

2. Step 2: Identify cause related to subnet

   This usually happens if the subnet ID is mistyped, deleted, or belongs to a different region/account.

3. Final Answer:

   The subnet ID provided does not exist in your AWS account or region. -> Option D

4. Quick Check:

   InvalidSubnetID error = wrong or missing subnet ID [OK]

Hint: Check subnet ID spelling and region first [OK]

Common Mistakes:

• Blaming DynamoDB table name for subnet errors
• Assuming internet gateway is required for VPC endpoint
• Ignoring subnet ID in error diagnosis

5. You want to ensure all DynamoDB traffic from your private subnet uses a VPC endpoint without going through the internet. Which setup is required?

hard

A. Create a DynamoDB VPC endpoint in your VPC, associate it with your private subnet, and update route tables accordingly.

B. Attach an internet gateway to your VPC and enable public IPs on your instances.

C. Create a NAT gateway and route all DynamoDB traffic through it.

D. Enable DynamoDB global tables for cross-region access.

Solution

1. Step 1: Understand private subnet traffic needs

   Private subnets do not have direct internet access, so to reach DynamoDB privately, a VPC endpoint is needed.

2. Step 2: Configure VPC endpoint and routing

   Create a DynamoDB VPC endpoint, associate it with the private subnet, and update route tables so traffic to DynamoDB uses the endpoint.

3. Step 3: Exclude internet gateway or NAT for this traffic

   Internet gateway or NAT gateway routes send traffic outside AWS, which is not desired for private access.

4. Final Answer:

   Create a DynamoDB VPC endpoint in your VPC, associate it with your private subnet, and update route tables accordingly. -> Option A

5. Quick Check:

   VPC endpoint + private subnet + route update = private DynamoDB access [OK]

Hint: Use VPC endpoint and route tables for private subnet access [OK]

Common Mistakes:

• Using internet gateway for private subnet traffic
• Routing DynamoDB traffic through NAT gateway unnecessarily
• Confusing global tables with network setup