Sample of an Elasticbeanstalk config file used by eb cli to create an autoscaled worker based on an SQS queue .ebextension/autoscaling.config

autoscaling.config.yml

# The name of this file is autoscaling.config. .yml has been added for syntax highlighting.

# References:
# http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/command-options-general.html#command-options-general-elasticbeanstalksqsd
# http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-template-resource-type-ref.html
# http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/environment-resources.html

# Create manually first those 2 resources:
# * the SQS queue, here its name is: my-sqs-queue
# * the RDS Postgres database
# * the Elasticache cluster (Redis)
# * the EC2 security group named: my-ec2-security-group-bridge (RDS-Elasticache access)

# Setup the correct IAM configuration with: autoscaling_iam_configuration.json

option_settings:

- namespace: aws:elasticbeanstalk:command
  option_name: Timeout
  value: 900

- namespace: aws:elasticbeanstalk:sqsd
  option_name: WorkerQueueURL
  value: https://sqs.us-east-1.amazonaws.com/123123123123/my-sqs-queue

- namespace: aws:elasticbeanstalk:sqsd
  option_name: HttpConnections
  value: 1

- namespace: aws:elasticbeanstalk:sqsd
  option_name: VisibilityTimeout
  value: 600

- namespace: aws:autoscaling:asg
  option_name: MinSize
  value: 1

- namespace: aws:autoscaling:asg
  option_name: MaxSize
  value: 100

- namespace: aws:autoscaling:launchconfiguration
  option_name: InstanceType
  value: m3.medium

- namespace: aws:autoscaling:launchconfiguration
  option_name: SecurityGroups
  value:
  - Ref: AWSEBSecurityGroup
  - my-ec2-security-group-bridge

Resources:

  ScalingPolicy1:
    Type: AWS::AutoScaling::ScalingPolicy
    Properties:
      ScalingAdjustment: 1
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName:
        Ref: AWSEBAutoScalingGroup
  QueueDepthAlarm1:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmDescription: "Alarm if queue is bigger than 3 messages in average"
      Namespace: AWS/SQS
      MetricName: ApproximateNumberOfMessagesVisible
      Dimensions:
      - Name: QueueName
        Value: my-sqs-queue
      Statistic: Average
      Period: 60
      EvaluationPeriods: 2
      Threshold: 5 
      ComparisonOperator: GreaterThanOrEqualToThreshold
      AlarmActions:
      - Ref: ScalingPolicy1

  ScalingPolicy2:
    Type: AWS::AutoScaling::ScalingPolicy
    Properties:
      ScalingAdjustment: 20
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName:
        Ref: AWSEBAutoScalingGroup
  QueueDepthAlarm2:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmDescription: "Alarm if queue is bigger than 10 messages in average"
      Namespace: AWS/SQS
      MetricName: ApproximateNumberOfMessagesVisible
      Dimensions:
      - Name: QueueName
        Value: my-sqs-queue
      Statistic: Average
      Period: 60
      EvaluationPeriods: 2
      Threshold: 10
      ComparisonOperator: GreaterThanOrEqualToThreshold
      AlarmActions:
      - Ref: ScalingPolicy2

  ScalingPolicy3:
    Type: AWS::AutoScaling::ScalingPolicy
    Properties:
      ScalingAdjustment: -5
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName:
        Ref: AWSEBAutoScalingGroup
  QueueDepthAlarm3:
    Type: AWS::CloudWatch::Alarm
    Properties:
      AlarmDescription: "Alarm if queue is less than 5 messages in average"
      Namespace: AWS/SQS
      MetricName: ApproximateNumberOfMessagesVisible
      Dimensions:
      - Name: QueueName
        Value: my-sqs-queue
      Statistic: Average
      Period: 60
      EvaluationPeriods: 2
      Threshold: 2
      ComparisonOperator: LessThanOrEqualToThreshold
      AlarmActions:
      - Ref: ScalingPolicy3

autoscaling_iam_configuration.json

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "EBSBucketAccess",
            "Action": [
                "s3:Get*",
                "s3:List*",
                "s3:PutObject"
            ],
            "Effect": "Allow",
            "Resource": [
                "arn:aws:s3:::elasticbeanstalk-*",
                "arn:aws:s3:::elasticbeanstalk-*/*"
            ]
        },
        {
            "Action": "s3:*",
            "Effect": "Allow",
            "Sid": "Mybucket",
            "Resource": [
                "arn:aws:s3:::my-bucket",
                "arn:aws:s3:::my-bucket/*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "ecs:Poll",
                "ecs:StartTask",
                "ecs:StopTask",
                "ecs:DiscoverPollEndpoint",
                "ecs:StartTelemetrySession",
                "ecs:RegisterContainerInstance",
                "ecs:DeregisterContainerInstance",
                "ecs:DescribeContainerInstances",
                "ecs:Submit*"
            ],
            "Resource": "*"
        },
        {
            "Sid": "QueueAccess",
            "Action": "sqs:*",
            "Effect": "Allow",
            "Resource": "*"
        },
        {
            "Sid": "MetricsAccess",
            "Action": [
                "cloudwatch:PutMetricData",
                "ec2:DescribeTags"
            ],
            "Effect": "Allow",
            "Resource": "*"
        },
        {
            "Sid": "ECSAccess",
            "Effect": "Allow",
            "Action": [
                "ecs:Poll",
                "ecs:StartTask",
                "ecs:StopTask",
                "ecs:DiscoverPollEndpoint",
                "ecs:StartTelemetrySession",
                "ecs:RegisterContainerInstance",
                "ecs:DeregisterContainerInstance",
                "ecs:DescribeContainerInstances",
                "ecs:Submit*"
            ],
            "Resource": "*"
        }, {
            "Sid": "DynamoPeriodicTasks",
            "Action": [
                "dynamodb:BatchGetItem",
                "dynamodb:BatchWriteItem",
                "dynamodb:DeleteItem",
                "dynamodb:GetItem",
                "dynamodb:PutItem",
                "dynamodb:Query",
                "dynamodb:Scan",
                "dynamodb:UpdateItem"
            ],
            "Effect": "Allow",
            "Resource": [
                "arn:aws:dynamodb:*:*:table/*-stack-AWSEBWorkerCronLeaderRegistry*"
            ]
        }, {
    ]
}