title: Accessing RDS from within a Docker container not getting through security group?
body: <p>I'm attempting to run a webserver that uses an RDS database with EC2 inside a docker container. </p>
  
  <p>I've setup the security groups so the EC2 host's role is allowed to access the RDS and if I try to access it from the host machine directly everything works correctly.</p>
  
  <p>However, when I run a simple container on the host and attempt to access the RDS, it get's blocked as if the security group weren't letting it through. After a bunch of trial and error it seemed that indeed the containers requests aren't appearing to come from the EC2 host so the firewall says no. </p>
  
  <p>I was able to work around this in the short-run by setting --net=host on the docker container, however this breaks a lot of great docker networking functionality like being able to map ports (ie, now I need to make sure each instance of the container listens on a different port by hand).</p>
  
  <p>Has anyone found a way around this? It seems like a pretty big limitation to running containers in AWS if you're actually using any AWS resources.</p>