I would like to create a lambda(vpc) which would access resources in vpc and make a request to services(REST API) via public application load balancer. I found out that vpc end point is better solution than creating a nat gateway.
I have created a vpc endpoint for elasticloadbalancing(by following steps at https://docs.aws.amazon.com/vpc/latest/userguide/vpce-interface.html#create-interface-endpoint) and given full access in the policy. I could not find how to access it from the lambda, what would be the URL to make the request?
Edit:
Thanks to John for the info that vpc endpoint is used to connect to ELB API. So Vpc endpoint would not solve our issue.
We have our infra in vpc which includes database(accessible within vpc only) and application servers running behind the ELB. For certain tasks we want to run lambda which will read database(for this reason lambda has to be inside vpc) and make API calls to our application using ELB. Since ELB is accessible from public dns only, lambda is not able to connect to ELB.
I have read that setting up NAT gateway is a solution. Are there other is simpler ways?
Yes, a NAT Gateway would allow the traffic from a private subnet to go out of the VPC and come back in to the Load Balancer's public IP addresses (via its Public DNS Name).
Alternatively, you could create an additional Internal Load Balancer that could accept traffic from within the VPC and send it to the Amazon EC2 instances.
Related
I have an EC2 based client that calls this public DNS of this AWS ELB in the same region and I am trying to save money on EC2-Internet public traffic and want to keep all the data within AWS cloud.
I want to know since I am calling from one AWS service to another. Does AWS services internally know how to keep this traffic within AWS ecosystem and save me internet data transfer charges?
Is setting up a VPC between the EC2 client -> AWS ELB is the only way to save on public internet traffic?
Thank you
what you are looking for is an internal load Balancer
The nodes of an internal load balancer have only private IP addresses. The DNS name of an internal load balancer is publicly resolvable to the private IP addresses of the nodes. Therefore, internal load balancers can only route requests from clients with access to the VPC for the load balancer.
You dont have to create vpc for that, default vpc will also work just make sure your ec2 and internal LB are in the same private vpc and subnet as prerequisite.
How to do it, read here
Coming to question Does AWS services internally know how to keep this traffic within AWS ecosystem and save me internet data transfer charges
If its within the same region using internet gateway it is free, if it uses nat gateway within same region it will cost, but if request falls cross region it is not free, Ref: Data transfer cost
I'm trying to figure out the following:
I have an API service deployed in the default VPC, and I have a ELB configured to access the service.
The ELB is attached to a security group sg-XXXXXXXX1 to restrict inbound traffic (open to all for outbound)
I'm now trying to create a lambda function that can call the API service. (using python requests)
I've tried the following and failed to succeed:
In the configuration > VPC section, I added sg-XXXXXXXX1 as the security group and the 4 default subnets
Added AWSLambdaVPCAccessExecutionRole to lambda role
Created a new security group sg-XXXXXXXX2 (all traffic for inbound and outbound), attached it to lambda, and added sg-XXXXXXXX2 to the inbound list (all traffic) for sg-XXXXXXXX1
Any ideas on what I did wrong? and how I can fix it?
Your ELB is most likely a public ELB (which is the default setting). The ELB DNS will resolve to a public IP address, not a VPC IP address. That means that the traffic going to the ELB will exit the VPC, go out to the Internet, and then back into AWS and into the ELB. When that happens, any association with the Lambda function's security group gets lost. Also, if your Lambda function isn't running in a subnet with a route to a NAT gateway it won't be able to access the Internet at all, so it is just going to timeout and fail when it tries to access the ELB.
To fix this, change the load balancer scheme to private, which will give the load balancer a private VPC IP address, and make it accessible only within the VPC.
We have 10 instances which we deployed the app using the AWS ECS and ELB
Due to security reasons the API allows request only through specific IP whitelisted IP addresses.
So we are planning to pass the request through the proxy
How to route an API request go through a proxy
We are using nginx
Any specific way to route an API request go through a proxy will be helful
You won't need NGINX as a proxy for this use-case, I'd propose to consider looking into using AWS NAT Gateways. NAT Gateway is a highly available AWS managed service that makes it easy to connect to the Internet from instances within a private subnet in an Amazon Virtual Private Cloud (Amazon VPC). Its the perfect place to provide a static IP to all your subnet's outbound traffic.
In order to provide a NAT Gateway with static IP (Elastic IP) for your cluster's outbound traffic. This will allow your different tasks running inside your ECS cluster's private subnets to look like a single requesting entity from an outsider's POV (in your case, the 3rd party API is the outsider). To achieve this, you will have to:
Create 2 route tables (1 for private subnets, 1 for public subnets)
Internet gateway on the public subnet
Elastic IP address
Create a NAT Gateway and attach the elastic IP to it (This will be the IP whitelisted to the 3rd party API)
Ensure that all your tasks are running inside private subnets of the VPC
Add a rule in your route table for your private subnets that redirects outbound 0.0.0.0/0 to the NAT Gateway.
Add a rule in your route table for your public subnets that redirects outbound traffic 0.0.0.0/0 to the internet gateway.
You should consider using NAT Gateway instead. I am assuming you already would have all your containers in a VPC, so you can create a new NAT Gateway within this VPC itself.
You can refer to articles attached below to do this:
https://docs.aws.amazon.com/appstream2/latest/developerguide/add-nat-gateway-existing-vpc.html
https://docs.aws.amazon.com/vpc/latest/userguide/vpc-nat-gateway.html
Note: NAT Gateways have price associated with them.
If needed, you can use the elastic IP provided by NAT Gateways on your lambdas as well.
When I configure an AWS Gateway VPC endpoint, a route table entry is created that points to the Gateway. Here, Gateway can be thought of performing the routing to AWS service (over private network).
However, for an AWS Inteface VPC endpoint, all that is visible is a Network interface that has a private IP address of the subnet. By default, a private IP can send traffic within the subnet or entire VPC provided Security Group and NACL allows the traffic. & it appears in this case there is no Route table entry to a Gateway or a Router for allowing traffic outside VPC.
How / Where is the interface routing the traffic to i.e. How does traffic leave the customer VPC?
Of course I understand that the traffic finally reaches the intended AWS service over private network but here I am trying to find out where is the Gateway or Router? Does AWS hide this implementation?
I cannot get my head around the fact that a simple Network Interface can accept traffic and route it to a service all by itself i.e. performing routing by itself? Clearly, in this case the traffic appears not flowing through the VPC router or another Gateway device.
I am aware this might be an AWS confidential implementation but any thoughts / idea on how they might have designed this feature?
It doesn't provide routing at all, by default a VPC interface endpoint when created will create an ENI per subnet in the VPC for you. It will also provide you a DNS name per each AZ and a global name that you can use within your applications.
In addition it supports the ability to have the AWS service domain name for the VPC interface endpoint be resolvable to the private IPs of the endpoint. As long as your VPC has DNS enabled it will first check the VPC private DNS resolver and then resolve it to the private IP rather than the public one.
This is done by adding an additional private hosted zone to your VPC which resolves service domains in your region such as ec2.us-east-1.amazonaws.com.
From the AWS side this is just an ENI created in your AWS VPC that is connected to one of AWS internal VPCs. It's actually possible to implement this for your own services too to share with another organisations VPCs, this is implemented using AWS PrivateLink.
For more information take a look at the Private DNS for interface endpoints page.
I have a target group which has two EC2 instances behind an application load balancer. I'm trying to build a lambda service to monitor EC2 instance healthy status outside of load balancer listener.
this lambda works as expected if VPC is not enabled. once I enabled VPC, then following code will fail:
client = boto3.client("elbv2", region_name=default_region_name)
tg_res = client.describe_target_groups(Names=[self.name])
API describe_target_groups will stuck there until timeout.
this VPC does have internet access and security group inbound/outbound temporary open for all IP.
any hit will be highly appreciated.
==========update==================
From lambda log, timeout happens at:
Starting new HTTPS connection (1): elasticloadbalancing.us-west-2.amazonaws.com
I checked network setting and I'm sure this VPC has NAT configuration.
this issue is solved by assigned another two internal access only subnets.
1) two EC2 instances are behind an ALB. EC2 instances are in subnet, let's say: west-2a-public, west-2b-public. These two subnets are internet facing and can assign public IP.
2) I assigned lambda service into same subnet: west-2a-public and west-2b-public but it doesn't work.
3) I then assigned lambda service into another two subnets: west-2a-private and west-2b-private. These two subnet does have NAT but doesn't have public IP assignment.
I guess the issue the router mapping but I need time to figure out exactly root cause. so far, it works.
You might need to edit your aws lambda function to add VPC support.
You can read more about here
I think the reason for this is the following: First, you need a NAT Gateway to access the Internet for Lambda functions as described here:
https://aws.amazon.com/de/blogs/aws/new-access-resources-in-a-vpc-from-your-lambda-functions/
Internet Access – As soon as you enable this functionality for a
particular function, the function no longer has access to the Internet
by default. If your function requires this type of access, you will
need to set up a Managed NAT Gateway in your VPC (see New – Managed
NAT (Network Address Translation) Gateway for AWS for more
information) or run your own NAT (see NAT Instances).
Second, if you have an EC2 instance or other Service such as a Load Balancer that need to be accessible inbound from the internet then you also need an Internet Gateway. However, it is not possible to assign an Internet Gateway and the NAT to one subnet. Therefore, you need to setup two subnets.
Here is an article describing the correct setup and configurations:
https://marcelog.github.io/articles/aws_lambda_internet_vpc.html