EC2 Instance call from lamda function - amazon-ec2

hello I want to call a api which is hoisted in Apache server on AWS EC2 server from my lambda function.
I have configured VPC for my lambda function according to my EC2 server instance with same security groups and same zone ,but still no luck.
Thanks in advance.

It appears that your situation is:
You want to make an HTTP/S API call from an AWS Lambda function to an Amazon EC2 instance
The Lambda function has been configured to connect to the same VPC as the EC2 instance
The Lambda function is reporting that it is unable to connect to the EC2 instance
I would recommend:
Create a Security Group (let's call it Lambda-SG) in the same VPC. It does not need any rules.
Configured the Lambda function to use the Security Group (in the Network section)
Create another Security Group (let's call it EC2-SG) and associate it with the EC2 instance. Add a rule that permits inbound access on the desired port, with the source set to ID of Lambda-SG.
That is the EC2-SG is saying that it will accept inbound connects from Lambda-SG on the desired port.
Merely putting resources in the same security group does not necessarily mean they can communicate. There needs to be a specific rule that permits the inbound access. The above method is the best way to do so.

Related

Security Group update to allow AWS Lambda function that is not attached to any VPC

There are two applications. One application is developed through AWS Lambda (present in Account A) and other application is deployed in ECS Fargate (present in Account B) in AWS.
The first application (AWS Lambda) is consuming an API (from the second application ECS Fargate). I need to allow the AWS Lambda function to access the ECS application (which is behind Application Load balancer) through the inbound rule in the security group.
Problem is AWS Lambda is not attached to any VPC and both applications are running in separate AWS accounts. How to solve this problem?
Note: It is an internal application not internet facing.
Note : Its internal application not internet facing.
If your ECS application's load balancer scheme is set to internal instead of public, then an AWS Lambda function that is not assigned to a VPC would never be able to access it. You are asking about security group rules, but there is no security group rule that will give something on the Internet access to a resource that is not exposed to the Internet.
Your only option to make this work is to move the Lambda function into a VPC, and establish VPC peering between the two VPCs.

Lambda function access to EC2 instance in same security group

I am trying to access my EC2 instance configured with elasticsearch from a configured lambda function.
I've added the lambda function to the same VPC and security group as the EC2 instance. I am not sure; what's causing the issue ?
I've EC2FullAccess permissions from lambda function
The correct security configuration should be:
A security group on the Lambda function (Lambda-SG). It does not require any Inbound rules. Leave the Outbound rules as standard 'allow all'.
A security group on the EC2 instance (Elasticsearch-SG) that allows Inbound connections on the desired port (9200?) from the Lambda-SG.
That is, Elasticsearch-SG specifically allows inbound connections from Lambda-SG.
Please note that security group rules apply to each instance individually. Putting two resources 'in' the same security group does not permit access between those resources unless there is a rule that allows inbound access from itself. Thus, it is better to put different security groups on each layer of resources.
There is no need to assign EC2FullAccess permissions to the Lambda function. That is only used to call AWS to do things like launching or terminating EC2 instances.

aws lambda access ec2

I have a python script running on AWS Lambda that tries to connect to a MariaDB I set up on an EC2 Instance.
The script can't execute because the security group of my EC2 instance only allows certain IPs. How can I allow Lambda functions to access?
The recommended way is to place your Lambda inside VPC. This will allow you to choose a subnet and a security group for your Lambda. So all you need to do after that is to modify your EC2 security group to allow connections either from the Lambda subnet (not so good) or from the Lambda security group (much better).

AWS Lambda: Unable to access SQS Queue from a Lambda function with VPC access

I have a Lambda function that needs to read messages from an SQS queue using it's URL. Then it needs to insert that data to Cassandra running on a server inside a VPC.
I am able to access the Cassandra server from my Lambda function, using it's private IP and configuring the security groups correctly.
However, I am not able to read messages from the SQS Queue. When I change the configuration of Lambda function to No VPC, then I am able to read the messages from the SQS Queue. However, with VPC settings, it just times out.
How can I overcome this ? I have checked the security group of my Lambda function has full outbound access to all IP addresses.
At the end of 2018, AWS announced support for SQS endpoints which provide
connectivity to Amazon SQS without requiring an internet gateway, network address translation (NAT) instance, or VPN connection.
There is a tutorial for Sending a Message to an Amazon SQS Queue from Amazon Virtual Private Cloud
See also the SQS VPC Endpoints Documentation for more information.
Its important to note that if you want to access SQS within the Lambda VPC there are a couple other things you need to do:
Make sure to specify the SQS region in your code. For example, I had to set my endpoint_url to "https://sqs.us-west-2.amazonaws.com"
Make sure that you have attached a "wide open" security group to the SQS VPC Interface, otherwise SQS will not work.
Make sure that your subnets in your Lambda VPC match what you have set up for your SQS VPC Interface.
Some services (e.g. S3) are offering VPC endpoints to solve this particular problem but SQS is not one of them. I think the only real solution to this problem is to run a NAT inside your VPC so the network traffic from the Lambda function can be routed to the outside world.
I ran into the same kind of problem when I was running lambda function with access to elasticache on the VPC. While the function was configured to run in the VPC, I wasnt able to talk to any other service (specifically codedeploy for me).
As #garnaat pointed out NAT seems to be the only way to go about solving this problem for services without VPC endpoints.
And like you pointed out, I also ran into the same trouble where I could'nt SSH into the machine(s) once I replaced the entry with the IGW in the route table. Seems like detaching the IGW starves the VPC of either the incoming traffic (mostly) or the outgoing traffic from or to the internet respectively. So here's what I did and it worked for me:
Create a new Subnet within the VPC
Now, when lambda runs, make sure lambda operates from this subnet.
You can do this by using aws-cli like so:
aws lambda update-function-configuration --function-name your-function-name --vpc-config SubnetIds="subnet-id-of-created-subnet",SecurityGroupIds="sg-1","sg-2"
Make sure you add all the security groups whose inbound and outbound traffic rules apply for your lambda function.
Next, go to Route Tables in the VPC console and create a new route table.
Here is where you add the NAT gateway to the target.
finally go to the Subnet Associations tab in the new route table and add the newly created subnet there.
Thats all this should get it working . Mind you, please treat this as only a workaround. I haven't done much digging and I have a very limited idea on how things get resolved internally while doing this. This might not be an ideal solution.
The ideal solution seems to be to design the VPC before hand. Use subnets to isolate resources/instances that need internet access and that dont(private and public subnets) and place appropriate gateways where needed.( so that you may not have to create a seperate subnet for this purpose later). Thanks
I was unable to get either of the other two answers to this question to work. Perhaps this is due to one or more mistakes on my part. Regardless, I did find a workaround that I wanted to share, in case I'm not alone with this problem.
Solution: I created two Lambda functions. The first Lambda function runs inside my VPC and performs the desired work (in mandeep_m91's case, that's a data insertion to Cassandra; in my case is was accessing an RDS instance). The second Lambda function lives outside the VPC, so I could hook it up to the SQS queue. I then had the second Lambda function call the first, using the information found this this StackOverflow Q&A answer. Note, the linked question has both node.js and Python examples in the answers.
This will effectively double the cost of making a function call, since each call results in two function executions. However, for my situation, the volume is so low it won't make a real difference.
To clarify a point above about a "wide open" security group, the group set on the endpoint needs to allow inbound access to SQS from your lambda function.
I created a security group for my endpoint that only opened 443 to my lambda's security group.

How to edit AWS EC2 instance's security groups to allow access to a lambda function only

I am running into a security related issue with AWS lambda and not sure what is the right way to resolve this.
Consider an EC2 instance A accessing the database on another EC2 instance B. If I want to restrict the accessibility of the DB on instance B to instance A only, I would modify the security group and add a custom TCP rule to allow access to only the public IP of instance A. So, this way, AWS will take care of everything and the DB server will not be accessible from any other IP address.
Now let us replace instance A by a lambda function. Since it is no longer an instance, there is no definite IP address. So, how do I restrict access to only the lambda function and block any other traffic ?
Have the Lambda job determine its IP, and dynamically update the instance B security group, then reset the security group when done.
Until there is support for Lambda running within a VPC this is the only option. Support for that has been announced for later this year. The following quote is from the referenced link above.
Many AWS customers host microservices within a Amazon Virtual Private
Cloud and would like to be able to access them from their Lambda
functions. Perhaps they run a MongoDB cluster with lookup data, or
want to use Amazon ElastiCache as a stateful store for Lambda
functions, but don’t want to expose these resources to the Internet.
You will soon be able to access resources of this type by setting up
one or more security groups within the target VPC, configure them to
accept inbound traffic from Lambda, and attach them to the target VPC
subnets. Then you will need to specify the VPC, the subnets, and the
security groups when your create your Lambda function (you can also
add them to an existing function). You’ll also need to give your
function permission (via its IAM role) to access a couple of EC2
functions related to Elastic Networking.
This feature will be available later this year. I’ll have more info
(and a walk-through) when we launch it.
I believe the below link will explain lambda permission model for you.
http://docs.aws.amazon.com/lambda/latest/dg/intro-permission-model.html

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