Merge pull request #582 from thomasmichaelwallace/master

Limitations of using Lambda with VPC resources.

README.md

@@ -1421,6 +1421,7 @@ Lambda
 - 🔸While adding/removing S3 buckets as triggers for Lambda function, this error may occur: "There was an error creating the trigger: Configuration is ambiguously defined. Cannot have overlapping suffixes in two rules if the prefixes are overlapping for the same event type." In this case, you can manually remove the Lambda event in the "Events" tab in the "Properties" section of the S3 bucket.
 - 🔸Managing the size of your deployment artifact can be a challenge, especially if using Java. Options to mitigate this include [proguard](https://www.guardsquare.com/en/proguard) and loading dependencies at runtime into /tmp.
 - When using DynamoDB as a trigger for your Lambda functions, this error may occur: "PROBLEM: internal Lambda error. Please contact Lambda customer support." This usually just means that Lambda can't detect anything in the DynamoDB stream within the last 48 hours. If the issue persists, deleting and recreating your trigger may help.
+- 🔸If your lambda needs access to resources in a VPC (for example ElastiCache or RDS), it will need to be deployed within it. This will increase cold-start times as an Elastic Network Interface (ENI) will have to be registered within the VPC for each concurrenat function. AWS also has a relatively low initial limit (350) on the number ENI's that can be created within an VPC, however this can be increased to the 1000s if a good case is made to AWS support.
 -	🔸 Lambda has several [**resource limits**](http://docs.aws.amazon.com/lambda/latest/dg/limits.html) as of 2017-06:
 	-	A **6MB** request or response payload size.
 	-	A **50 MB** limit on the compressed .zip/.jar file deployment package size.