AWS Lambda Function Timeout on Connecting To RDS Database through RDS Proxy - amazon-web-services

I'm trying to test AWS RDS proxy so I created a lambda function and done all steps that are present in this official link
https://aws.amazon.com/blogs/compute/using-amazon-rds-proxy-with-aws-lambda
store RDS credentials in Secret Manager
create new role and also add Trust Policy
in lambda function, from the AWS console, add proxy and its status is available.
When I execute the lambda function, it times out with no errors it seems like the error might be on connecting to db with rds proxy because when I run the lambda function again without proxy, it works just fine.
I initially thought that it might be a security group issue, so I edit the security group of RDS Proxy and update inbound and allow 0.0.0.0 (outbound was already 0.0.0.0).
I used defaut VPC in RDS Database and RDS Proxy. The endpoint of RDS database is public.

Since RDS proxy is not available outside the VPC. Configure your lambda function to run inside the VPC. The following link will help:
https://docs.aws.amazon.com/lambda/latest/dg/configuration-vpc.html

Late answer.. thought these might help others.
You have to keep your lambdas inside the same VPC and subnets to access RDS proxy.
In any case if you want to access third party web api from your lambda, you have make the lambda subnets private (no Internet Gateway in route table) and assign a NAT gateway which is tied with a public subnet.
If you are accessing other AWS services which are out of VPC like S3, Secret Manager etc. then you have to create VPC endpoints for those services in your VPC.

Related

Proper way of working with DocumentDB and Lambda

I am connecting to AWS DocumentDB from a Lambda function. In order to be able to do this I had to attach lambda to the default VPC (that's where DocumentDB cluster is running) and the default (public) subnets. But, this has caused my Lambda to timeout whenever trying make an outbound request, e.g. push message to SQS. This, I want to avoid.
So what is the recommended way of connecting to DocumentDB without loosing functionality that occurs when putting Lambda in the VPC? There's gotta be a simple solution.
Lambda functions in a VPC never get a public IP address. So if the function needs to access both VPC resources and other resources outside of the VPC the function has to be deployed only to private subnets with routes to a NAT Gateway.
Alternatively, if the only external resources you need to access are other AWS services, then you could add VPC Endpoints for those services to the VPC.

How to Access RDS Proxy from a Different AWS Region?

I have a RDS database and a RDS proxy in one region.
However, I also have a lambda function in a different region that need to connect to the RDS proxy in the first region.
I know that the RDS proxy can't be publicly accessible and need to be within the same VPC as the instance trying to connect to it.
Is there a way to allow a lambda function to connect to a RDS proxy in a different region?
I know that an RDS DB can be publicly accessible, however I was getting sql timeout errors in my lambda functions, which is why I chose to use a RDS proxy.
I know that the RDS proxy can't be publicly accessible and need to be
within the same VPC as the instance trying to connect to it.
I think the part in bold is partially incorrect. The RDS proxy has to be in the same VPC as the RDS database. As far as I can tell, the instance trying to connect doesn't need to be in the same VPC, I think it could also be in a peered VPC.
To answer your question, I would suggest placing the Lambda function in a VPC in the other region, and create a VPC peering connection between the two VPCs.

Accessing AWS services from a lambda in a private subnet

I'm working on an serverless application the works with a database in RDS. For security reasons, both the application (Lambda) and the database are located in a private subnet in a VPC.
I also want to access AWS services from the application - for example, I would like to access secret manager to obtain database credentials, put an rule in EventBridge and use STS service.
I know that I can use VPC endpoints and deploy interface endpoint in my VPC for each service of interest.
My question is as follows - the sole reason that the application is in the private subnet is database access. Why shouldn't I just create another lambda, that is not my VPC and can access these services easily and for free and just invoke it from my main application?
What are the security risks? What am I missing?
Thanks
If I understand correctly, you would want to create another Lambda which runs outside of the VPC and be invoked by the Lambda which is inside the VPC.
Well you can certainly do that, but this also would require to have either a NAT gateway to have access to the outside Lambda or a VPC endpoint for the Lambda control-plane. Moreover, you will double pay for each separate Lambda invocations, and you also would want to keep an eye on the running time of the Lambdas.
can access these services easily and for free
Nothing is really free in AWS. You will have to pay for the ENI used by the VPC endpoint or for the NAT gateway. And also for the Lambda invocations.
What are the security risks?
Security-wise, you are not really missing anything.

How do I create an AWS VPC Endpoint for Elasticsearch?

I have a lambda function which must be placed in a VPC because it communicates over a VPC peering connection. I also need it to upload to my Elasticsearch Service domain (not in a VPC because it is publicly accessible). But currently when Lambda tries to talk to ES, it times out.
I ran into this problem with Secrets Manager, so I went into the lambda's VPC, clicked on Endpoints, and created a Secrets Manager endpoint. I would like to do the same with Elasticsearch Service, but it doesn't show up in my list of AWS Services, which is odd because it definitely is an AWS Service.
Any idea how I can add an endpoint for Elasticsearch Service in my VPC so my Lambda function can talk to it? Thanks!
There is no VPC endpoint for ES. The services that support the endpoints are listed here.
Regarding the timeout, you would have to provided detailed description of your VPC setup, subnets, route tables, lambda and explain how did you setup your ES and how do you try to access it from VPC. Its difficult to speculate why it times out without all the details.
But since your ES is public, one possibility could be because lambda in VPC will not be able to connect to it without the use of NAT gateway. By default, lambda in a VPC does not have internet connectivity.

Access EC2 Instance Service Via AWS Lambda Function

I have a EC2 Instance which only have Private IP and I have installed the Apache Kafka on same Instance running on say 10.0.4.44:9092.
Now, I have created the AWS Lambda Function which read the document from given Bucket and sent the Document body to Apache Kafka running on EC2 Instance.
Now, AWS Lambda is unable to access the EC2 Instance Service.
How Can I grant access to Lambda for accessing Apache kafka Service on EC2?
You need to add the Lambda function to the VPC the EC2 server is running in. Here's the announcement blog post of Lambda VPC support with a walk through for setting it up. Here's the official documentation.
A Lambda function in a VPC will not get a public IP address. This means it won't be able to access anything that is outside the VPC. Since you also need to access S3 you will need to setup an S3 VPC Endpoint so that your function will still have S3 access.
If your function needs access to other things outside the VPC then you will have to add it to a private subnet of the VPC with a NAT Gateway attached.