ElastiCache

[ralcorta]

Hello everyone!

I encountered an issue while trying to interact between a Lambda and Elasticache, which I see repeatedly commented on in some localstack issues that took me a while to resolve. I think it's a good idea to add a clarification within the Elasticache section or somewhere else to comment on the following:

aws/aws-sam-cli#318 (comment)

Even if you have configured a Lambda with the correct VPC, subnets, and security groups, it cannot internally communicate with this service (and perhaps more cases that I haven't tested yet). To resolve this, you need to assign the internal Docker host: host.docker.internal (in addition to the port explained 4510).

I don't see this in the documentation, and it would save a lot of time for anyone who wants to use a more complex network within localstack.