Getting Cannot connect to the Docker daemon on AWS EC2 runner

I've been trying to setup a runner on my aws ec2 instance, follow installation steps and register the runner, everything seems fine except that when trying to build and push my image I'm getting:

Using Docker executor with image docker:latest ...
Pulling docker image docker:dind ...
Starting service docker:dind ...
Waiting for services to be up and running...

*** WARNING: Service runner-0da6f169-project-1533741-concurrent-0-docker probably didn't start properly.

API error (500): Cannot link to a non running container: /runner-0da6f169-project-1533741-concurrent-0-docker AS /runner-0da6f169-project-1533741-concurrent-0-docker-wait-for-service/runner-0da6f169-project-1533741-concurrent-0-docker

2016-08-31T03:33:15.733979873Z mount: mounting none on /sys/kernel/security failed: Permission denied
2016-08-31T03:33:15.734002602Z Could not mount /sys/kernel/security.
2016-08-31T03:33:15.734006887Z AppArmor detection and --privileged mode might break.
2016-08-31T03:33:15.734604225Z mount: mounting none on /tmp failed: Permission denied

*********

Pulling docker image docker:latest ...
Running on runner-0da6f169-project-1533741-concurrent-0 via ip-172-31-50-171...
Fetching changes...
HEAD is now at 83af5d7 Removing dind from gitlab-ci.yml
From https://gitlab.com/appoptimista/optimista-web
   83af5d7..736bc6d  master     -> origin/master
Checking out 736bc6dd as master...
Checking cache for build...
$ source ci/prepare
$ docker info
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
ERROR: Build failed: exit code 1

I follow these steps https://about.gitlab.com/2016/04/19/how-to-set-up-gitlab-runner-on-digitalocean/ with exception of the Digital Ocean setup, my EC2 instance is an Ubuntu t2.micro .

I'm able to run docker info on the ec2 instance and it's ok.

Here's my gitlab-ci.yml file:

image: docker:latest
services:
- docker:dind

variables:
  DOCKER_DRIVER: overlay

cache:
  key: "$CI_BUILD_NAME"
  paths:
  - node_modules/

stages:
- build

before_script:
- source ci/prepare

build:
  stage: build
  script:
  - docker info
  - docker_build_push $CI_BUILD_SHA

Is there a missing step or something that I need to take into account ?