Can we use both DynamoDb and VPC to an aws lambda? - amazon-web-services

I am working on a AWS lambda in which i want to use DynamoDB and a VPC(Amazon elasticcache for redis). But I was getting time out error when trigger lambda

You either need to create a DyanmoDB VPC Endpoint in the VPC, or add a NAT Gateway to the VPC, and only deploy the Lambda function in subnets that have a route to the NAT Gateway.

Depending on the VPC configuration subnet/Security Group of your lambda,
If your lambda is in a private subnet :
If you want a secure internal way, you can pass with VPC endpoint
Else if you want to pass with internet, you must have a NAT Gateway.
Check also the security groups/NACLS....

Related

One VPC Endpoint for multiple services in AWS

I have VPC with two private subnets in two different AZ and
I am trying to create a VPC Endpoint for connecting lambda to my database in private one of subnet
But I need SNS also for sending message to users based on my lambda function
Do I need to create another endpoint for SNS in that subnet or I can attach multiple services to the same endpoint
I know NAT gateway is an option but it is costly than endpoints
Please suggest best way to do this
Thanks,
Monika
No. A VPC Endpoint is always for a specific service.
By the way, you do not require a VPC Endpoint for Lambda in your situation. Simply configure the AWS Lambda function to connect to the private subnets in the VPC. This is an in-built capability of Lambda functions and the do not require a VPC Endpoint to access the subnets.

Access AWS Batch from a lambda instance

I'm getting timeout errors when trying to create AWS Batch jobs using the AWS Javascript SDK from a Lambda.
How can I connect to AWS Batch from a Lambda instance besides creating public/private subnets with a NAT gateway?
The only other way is to not put your lambda in VPC. If you really need your function to be in VPC, the only way is to place it in private subnet and then use NAT in public subnet. This is because there is no VPC interface endpoint for AWS Batch.
You could also have second lambda function, not in VPC. So the main function in the VPC, invokes the second one which operates on AWS Batch. This will work, because AWS Lambda has interface endpoint which allows you to invoke functions from VPC without internet access.

lambda timeout when calling parameter store

I have a lambda function that calls the parameter store to retrieve a credential. The code is as follows:
import boto3
ssm = boto3.client('ssm')
parameter = ssm.get_parameter(Name='credentials', WithDecryption=True)
print(parameter['Parameter']['Value'])
I have given AmazonSSMFullAccess to the lambda role. The lambda has a VPC which later I'll use it to connect to a Redshift database without public access. The inbound and outbound rules are as follows:
There is a post AWS Lambda cannot connect to Parameter Store which mentions that if the lambda requires VPC, then add a NAT gateway.
In the lambda subnet route table: , there seems to be already a route that goes to the internet?
But I am still getting lambda time-out errors :(
there seems to be already a route that goes to the internet?
Sadly, it does not. It seems you placed your lambda in a public subnet with route to internet gateway (IGW). However, you have to use private subnet with a route to NAT gateway. IGW and NAT are two different things. Have a look at this AWS guide how to make it work:
How do I give internet access to a Lambda function that's connected to an Amazon VPC?
Alternatively, you can setup VPC interface endpoint for Paramter store. Then you don't need internet access for your Lambda function.

How to configure vpc for a lambda and dynamodb?

I'm creating a VPC in aws, and plan to add dynamodb and lambda to access to dynamo. If dynamodb is in a private subnet, what else do i need for lambda to connect to the dynamo. If lambda is invoked by API gateway , can lambda and dynamodb be under same private subnet?
DynamoDB is not located in your VPC. If you want to access DynamoDB via the private network from Lambda, you can use the DynamoDB VPC Gateway endpoint. A route will be added to your subnet route table, all traffic to DynamoDB will route through AWS internal network.
Things to setup:
Private subnet
DynamoDB VPC endpoint (Gateway type, use interface type (cost $) if you want to connect via private IP)
VPC Lambda
If you want the API Gateway also be private, setup private API Gateway and API Gateway VPC endpoint

How to connect elasticache and dynamoDb from aws-lambda without using NAT Gateway

I need to connect dynamoDb and elasticache from aws-lambda (otherthan using NAT Gateway).
ElastiCache provides essential caching methods along with help in making the Lambda state-ful. The concern is that for Lambda to work nice with DynamoDB it should be set to NoVPC.
If we have to use ElastiCache, Lambda and both have to be in the same VPC.TO use Both ElastiCache and DynamoDB together is quite a challenge specially with Lambda. Given the VPC challenges.Do you have any suggestions to make this easier?
A Lambda function would have to have VPC access to connect to ElastiCache, and it would have to have access to resources outside the VPC to access DynamoDB so it would require a NAT gateway. There is no way to provide access to both of those services to a single Lambda function without enabling VPC access and setting up a NAT gateway.
If you just need a Redis server and aren't required specifically to use ElasiCache, then you could use a RedisLabs instance which wouldn't require you to enable VPC access on your Lambda function.
There is now a relatively easy solution for DynamoDb access from a VPC: VPC Endpoints.
"Previously, if you wanted your EC2 (elroy: or lambda) instances in your VPC to be able to access DynamoDB, you had two options. You could use an Internet Gateway (with a NAT Gateway or assigning your instances public IPs) or you could route all of your traffic to your local infrastructure via VPN or AWS Direct Connect and then back to DynamoDB."
"A VPC endpoint for DynamoDB enables Amazon EC2 instances in your VPC to use their private IP addresses to access DynamoDB with no exposure to the public Internet...Your EC2 instances do not require public IP addresses, and you do not need an Internet gateway, a NAT device, or a virtual private gateway in your VPC. You use endpoint policies to control access to DynamoDB. Traffic between your VPC and the AWS service does not leave the Amazon network. "
The above quotes come from the links below. Note the the references to "EC2 instances" apply to lambda contexts as well.
See https://aws.amazon.com/blogs/aws/new-vpc-endpoints-for-dynamodb/
and
http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/vpc-endpoints-dynamodb.html