error modifying Lambda Function configuration : ValidationException with Lambda and VPC - amazon-web-services

Question

I am building a lambda in terraform using it's AWS module and my code is as below:
module "lambda_function" {
# * Lambda module configs
source = "terraform-aws-modules/lambda/aws"
version = "3.0.0"
# * Lambda Configs
function_name = "${var.function_name}-${var.env}"
description = "My Project"
handler = local.constants.lambda.HANDLER
runtime = local.constants.lambda.VERSION
memory_size = 128
cloudwatch_logs_retention_in_days = 14
source_path = "./function/"
timeout = local.constants.lambda.TIMEOUT
create_async_event_config = true
maximum_retry_attempts = local.constants.lambda.RETRIES_ATTEMPT
layers = [
data.aws_lambda_layer_version.layer_requests.arn
]
environment_variables = {
AWS_ACCOUNT = var.env
SLACK_HOOK_CHANNEL = var.SLACK_HOOK_CHANNEL
}
tags = {
Name = "${var.function_name}-${var.env}"
}
trusted_entities = local.constants.lambda.TRUSTED_ENTITIES
}
This code works fine and the lambda get's deployed. Now i need to put the lambda in the VPC. When i add the code below in the resource block, i get the error error modifying Lambda Function (lambda_name) configuration : ValidationException: │ status code: 400, request id: de2641f6-1125-4c83-87fa-3fe32dee7b06 │ │ with module.lambda_function.aws_lambda_function.this[0], │ on .terraform/modules/lambda_function/main.tf line 22, in resource "aws_lambda_function" "this": │ 22: resource "aws_lambda_function" "this" {
The code for the vpc is:
# * VPC configurations
vpc_subnet_ids = ["10.21.0.0/26", "10.21.0.64/26", "10.21.0.128/26"]
vpc_security_group_ids = ["sg-ffffffffff"] # Using a dummy value here
attach_network_policy = true
If i use the same values in the AWS console and deploy the lambda in the VPC, it works fine.
Can someone please help ?

Answer 1

You have to provide valid subnet ids, not CIDR ranges. So instead of
vpc_subnet_ids = ["10.21.0.0/26", "10.21.0.64/26", "10.21.0.128/26"]
it should be
vpc_subnet_ids = ["subnet-asfid1", "subnet-asfid2", "subnet-as4id1"]