Accessing Parameter Store from VPC / Lambda

Question

My lambda function can access Systems Manager parameters (ssm.getParameter) when NOT in a VPC. When I add the lambda function to my VPC, I lose access to SSM. The function times out.

Clearly I am missing a security group setting or something but can't figure it out. What do I need to do to enable lambda access to SSM when running it in my VPC?

Answer 1

To add to @b.b3rn4rd

I myself finished everything after following Amazon's https://docs.aws.amazon.com/systems-manager/latest/userguide/sysman-setting-up-vpc.html but was still getting timeout errors when calling SSM from lambdas.

I found the answer in the following article https://aws.amazon.com/premiumsupport/knowledge-center/ec2-systems-manager-vpc-endpoints/ You also need to add another inbound rule for your security group where you allow inbound requests for HTTPS in your VPC, the source will be the security group that you're using for Lambdas.

It should be something like Type:HTTPS Protocol:TCP Port:443 Source:[security group]