Docker Registry CloudFormation template (better version here: https://github.com/mbabineau/cloudformation-docker-registry)

docker-registry.template.json

{
  "AWSTemplateFormatVersion" : "2010-09-09",

  "Description" : "Launches a Docker Registry.",

  "Parameters" : {
    "InstanceType" : {
      "Description" : "EC2 instance type",
      "Type" : "String",
      "Default" : "m1.small",
      "AllowedValues" : [ "t1.micro","m1.small","m1.medium","m1.large","m1.xlarge","m2.xlarge","m2.2xlarge","m2.4xlarge","m3.xlarge","m3.2xlarge","c1.medium","c1.xlarge","cc1.4xlarge","cc2.8xlarge","cg1.4xlarge"],
      "ConstraintDescription" : "must be a valid EC2 instance type."
    },
    "KeyName" : {
      "Description" : "Name of an existing EC2 KeyPair to enable SSH access to the instances",
      "Type" : "String"
    },
    "DockerAmi" : {
      "Description" : "Docker-capable AMI to use for the registry servers",
      "Type" : "String"
    },
    "ClientSecurityGroup" : {
      "Description" : "Name of the security group from which clients may access the registry",
      "Type" : "String"
    },
    "DnsPrefix" : {
      "Description" : "Prefix for the registry's DNS record (<prefix>.<zone>)",
      "Type": "String",
      "Default": "docker"
    },
    "DnsZone" : {
      "Description" : "Route53-hosted zone to use for the registry's DNS record (<prefix>.<zone>) (e.g., 'mycompany.com')",
      "Type": "String"
    },
    "RegistryImage" : {
      "Description" : "Name of the Docker Registry image to use (format: 'registry:port/repository:version'",
      "Type" : "String",
      "Default" : "samalba/docker-registry"
    },
    "S3Bucket" : {
      "Description" : "Bucket to use for Docker images (e.g., 'mycompany-docker')",
      "Type" : "String",
    },
    "ClusterSize": {
      "Description" : "Number of Docker Registry servers to run",
      "Type" : "Number",
      "Default" : 1
    },
    "AdminLocation" : {
      "Description" : "IP address range that can be used to manage the instance and the registry",
      "Type": "String",
      "MinLength": "9",
      "MaxLength": "18",
      "Default": "0.0.0.0/0",
      "AllowedPattern": "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})/(\\d{1,2})",
      "ConstraintDescription": "must be a valid IP CIDR range of the form x.x.x.x/x."
    }
  },

  "Resources" : {
    "IAMUser" : {
      "Type" : "AWS::IAM::User",
      "Properties" : {
        "Policies" : [{
          "PolicyName" : "S3Access",
          "PolicyDocument" : {
            "Statement": [{
              "Effect"   : "Allow",
              "Action"   : "s3:*",
              "Resource" : { "Fn::Join" : ["", ["arn:aws:s3:::", {"Ref" : "S3Bucket"} , "/*"]]}
            }]
          }
        },
        {
          "PolicyName" : "IAMAccess",
          "PolicyDocument" : {
            "Statement" : [{
              "Effect"    : "Allow",
              "NotAction" : "iam:*",
              "Resource"  : "*"
            }]
          }
        }]
      }
    },

    "HostKeys" : {
      "Type" : "AWS::IAM::AccessKey",
      "Properties" : {
        "UserName" : { "Ref" : "IAMUser" }
      }
    },

    "ServerGroup" : {
      "Type" : "AWS::AutoScaling::AutoScalingGroup",
      "Properties" : {
        "AvailabilityZones" : { "Fn::GetAZs" : "" },
        "LaunchConfigurationName" : { "Ref" : "LaunchConfig" },
        "MinSize" : "1",
        "MaxSize" : "1",
        "DesiredCapacity" : "1",
        "LoadBalancerNames" : [ { "Ref" : "ElasticLoadBalancer" } ],
        "VPCZoneIdentifier" : { "Ref" : "Subnets" }
      }
    },

    "LaunchConfig" : {
      "Type" : "AWS::AutoScaling::LaunchConfiguration",
      "Metadata" : {
        "AWS::CloudFormation::Init" : {
          "config": {
            "files" : {
              "/opt/docker-registry/config.yml" : {
                "content" : { "Fn::Join" : ["\n", [
                  "prod:",
                  "    loglevel: warn",
                  "    storage: s3",
                  "    s3_access_key: {{access_key}}",
                  "    s3_secret_key: {{secret_key}}",
                  "    s3_bucket: {{s3_bucket}}",
                  "    boto_bucket: {{s3_bucket}}",
                  "    storage_path: /srv/docker",
                  "    secret_key: {{magic_string}}"
                ]]},
                "context" : {
                  "access_key"  : { "Ref" : "HostKeys" },
                  "secret_key"  : { "Fn::GetAtt" : ["HostKeys", "SecretAccessKey"]},
                  "s3_bucket"   : { "Ref" : "S3Bucket"},
                  "magic_string": "fL3YHeP1cmCHH5FWm1PKaO7cdo0VXkabAgiSEestXYZDgAiQcDCsTiWpOaukB1e9"
                },
                "mode"    : "000700",
                "owner"   : "root",
                "group"   : "root"
              }
            }
          }
        }
      },
      "Properties" : {
        "KeyName" : { "Ref" : "KeyName" },
        "ImageId" : { "Ref" : "DockerAmi" },
        "SecurityGroups" : [ { "Ref" : "ServerSecurityGroup" } ],
        "AssociatePublicIpAddress": "true",
        "InstanceType" : { "Ref" : "InstanceType" },
        "UserData"       : { "Fn::Base64" : { "Fn::Join" : ["", [
          "#!/bin/bash -ex\n",

          "# Helper function\n",
          "function error_exit\n",
          "{\n",
          "  cfn-signal -e 1 -r \"$1\" '", { "Ref" : "WaitHandle" }, "'\n",
          "  exit 1\n",
          "}\n",

          "cfn-init -s ", { "Ref" : "AWS::StackName" }, " -r LaunchConfig ",
          "    --access-key ",  { "Ref" : "HostKeys" },
          "    --secret-key ", {"Fn::GetAtt": ["HostKeys", "SecretAccessKey"]},
          "    --region ", { "Ref" : "AWS::Region" }, " || error_exit 'Failed to run cfn-init'\n",

          "# Post-cfn work\n",
          "sudo docker run -d",
          "   -p 5000:5000",
          "   -v /opt/docker-registry:/registry-conf",
          "   -e DOCKER_REGISTRY_CONFIG=/registry-conf/config.yml",
          "   -e SETTINGS_FLAVOR=prod",
          "   ", { "Ref": "RegistryImage" }, "|| error_exit 'Failed to launch Docker container'\n",

          "# All is well so signal success\n",
          "cfn-signal -e 0 -r \"Stack setup complete\" '", { "Ref" : "WaitHandle" }, "'\n",

          "#EOF"
        ]]}}
      }
    },

    "ServerSecurityGroup" : {
      "Type" : "AWS::EC2::SecurityGroup",
      "Properties" : {
        "GroupDescription" : "Enable SSH and Registry access",
        "VpcId" : { "Ref" : "VpcId" },
        "SecurityGroupIngress" :
          [ { "IpProtocol" : "tcp", "FromPort" : "22", "ToPort" : "22", "CidrIp" : { "Ref" : "AdminLocation"} },
            { "IpProtocol" : "tcp", "FromPort" : "5000", "ToPort" : "5000", "SourceSecurityGroupId" : { "Ref" : "LbSecurityGroup"} }]
      }
    },

    "LbSecurityGroup" : {
      "Type" : "AWS::EC2::SecurityGroup",
      "Properties" : {
        "GroupDescription" : "Enable Registry access",
        "VpcId" : { "Ref" : "VpcId" },
        "SecurityGroupIngress" :
          [ { "IpProtocol" : "tcp", "FromPort" : "80", "ToPort" : "80", "CidrIp" : { "Ref" : "AdminLocation"} },
            { "IpProtocol" : "tcp", "FromPort" : "80", "ToPort" : "80", "SourceSecurityGroupId" : { "Ref" : "ClientSecurityGroup"} } ]
      }
    },

    "ElasticLoadBalancer" : {
      "Type" : "AWS::ElasticLoadBalancing::LoadBalancer",
      "Properties" : {
        "SecurityGroups": [{ "Ref": "LbSecurityGroup" }],
        "Subnets": { "Ref": "Subnets" },
        "Listeners" : [ {
          "LoadBalancerPort" : "80",
          "InstancePort" : "5000",
          "Protocol" : "HTTP"
        } ],
        "HealthCheck" : {
          "Target" : "HTTP:5000/",
          "HealthyThreshold" : "3",
          "UnhealthyThreshold" : "5",
          "Interval" : "30",
          "Timeout" : "5"
        }
      }
    },

    "DnsRecord" : {
      "Type" : "AWS::Route53::RecordSet",
      "Properties" : {
        "HostedZoneName" : { "Fn::Join" : [ "", [{"Ref" : "DnsZone"}, "." ]]},
        "Comment" : "Docker Registry",
        "Name" : { "Fn::Join" : [ "", [{"Ref" : "DnsPrefix"}, ".", {"Ref" : "DnsZone"}, "."]]},
        "Type" : "CNAME",
        "TTL" : "900",
        "ResourceRecords" : [ { "Fn::GetAtt" : [ "ElasticLoadBalancer", "DNSName" ] } ]
      }
    },

    "WaitHandle" : {
      "Type" : "AWS::CloudFormation::WaitConditionHandle"
    }
  },

  "Outputs" : {
    "DnsAddress" : {
      "Description" : "Docker Registry",
      "Value" :  { "Ref" : "DnsRecord" }
    }
  }
}