Class: EcsDeploy::InstanceFluctuationManager

Inherits:
Object
  • Object
show all
Defined in:
lib/ecs_deploy/instance_fluctuation_manager.rb

Constant Summary collapse

MAX_UPDATABLE_ECS_CONTAINER_COUNT = 
10
MAX_DETACHEABLE_EC2_INSTACE_COUNT = 
20
MAX_DESCRIBABLE_ECS_TASK_COUNT = 
100

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(region:, cluster:, auto_scaling_group_name:, desired_capacity:, logger:) ⇒ InstanceFluctuationManager

Returns a new instance of InstanceFluctuationManager.



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# File 'lib/ecs_deploy/instance_fluctuation_manager.rb', line 13

def initialize(region:, cluster:, auto_scaling_group_name:, desired_capacity:, logger:)
  @region = region
  @cluster = cluster
  @auto_scaling_group_name = auto_scaling_group_name
  @desired_capacity = desired_capacity
  @logger = logger
end

Instance Attribute Details

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



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# File 'lib/ecs_deploy/instance_fluctuation_manager.rb', line 7

def logger
  @logger
end

Instance Method Details

#decrease ⇒ Object 



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# File 'lib/ecs_deploy/instance_fluctuation_manager.rb', line 42

def decrease
  asg = fetch_auto_scaling_group

  decrease_count = asg.desired_capacity - @desired_capacity
  if decrease_count <= 0
    @logger.info("The capacity is already #{asg.desired_capacity}")
    return
  end
  @logger.info("Decrease desired capacity of #{@auto_scaling_group_name}: #{asg.desired_capacity} => #{@desired_capacity}")

  container_instances = ecs_client.list_container_instances(cluster: @cluster).flat_map do |resp|
    ecs_client.describe_container_instances(
      cluster: @cluster,
      container_instances: resp.container_instance_arns
    ).container_instances
  end

  az_to_container_instances = container_instances.sort_by {|ci| - ci.running_tasks_count }.group_by do |ci|
    ci.attributes.find {|attribute| attribute.name == "ecs.availability-zone" }.value
  end
  if az_to_container_instances.empty?
    @logger.info("There are no instances to terminate.")
    return
  end

  target_container_instances = extract_target_container_instances(decrease_count, az_to_container_instances)

  @logger.info("running tasks: #{ecs_client.list_tasks(cluster: @cluster).task_arns.size}")
  all_running_task_arns = []
  target_container_instances.map(&:container_instance_arn).each_slice(MAX_UPDATABLE_ECS_CONTAINER_COUNT) do |arns|
    @logger.info(arns)
    ecs_client.update_container_instances_state(
      cluster: @cluster,
      container_instances: arns,
      status: "DRAINING"
    )
    arns.each do |arn|
      all_running_task_arns.concat(list_running_task_arns(arn))
    end
  end

  stop_tasks_not_belonging_service(all_running_task_arns)
  wait_until_tasks_stopped(all_running_task_arns)

  instance_ids = target_container_instances.map(&:ec2_instance_id)
  terminate_instances(instance_ids)
  @logger.info("Succeeded in decreasing instances!")
end

#increase ⇒ Object 



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# File 'lib/ecs_deploy/instance_fluctuation_manager.rb', line 21

def increase
  asg = fetch_auto_scaling_group

  @logger.info("Increase desired capacity of #{@auto_scaling_group_name}: #{asg.desired_capacity} => #{asg.max_size}")
  as_client.update_auto_scaling_group(auto_scaling_group_name: @auto_scaling_group_name, desired_capacity: asg.max_size)

  # Run in background because increasing instances may take time
  Thread.new do
    loop do
      cluster = ecs_client.describe_clusters(clusters: [@cluster]).clusters.first
      instance_count = cluster.registered_container_instances_count
      if instance_count == asg.max_size
        @logger.info("Succeeded in increasing instances!")
        break
      end
      @logger.info("Current registered instance count: #{instance_count}")
      sleep 5
    end
  end
end