Merge pull request #26 from comtravo/chore/ecs-cluster

Move ecs-cluster Terraform module to monorepo

ecs-cluster/README.md

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+## Requirements
+
+| Name | Version |
+|------|---------|
+| terraform | >= 0.12 |
+
+## Providers
+
+| Name | Version |
+|------|---------|
+| aws | n/a |
+| null | n/a |
+| template | n/a |
+
+## Inputs
+
+| Name | Description | Type | Default | Required |
+|------|-------------|------|---------|:--------:|
+| aws\_ami | The AWS ami id to use | `string` | n/a | yes |
+| cluster | The name of the cluster | `string` | n/a | yes |
+| cluster\_attributes | The ECS atributes for the cluster | `map(string)` | `{}` | no |
+| cluster\_uid | The name of the cluster | `string` | n/a | yes |
+| custom\_userdata | Inject extra command in the instance template to be run on boot | `string` | `""` | no |
+| depends\_id | Inter module dependency hack | `string` | n/a | yes |
+| desired\_capacity | The desired capacity of the cluster | `number` | `1` | no |
+| ebs\_root\_volume\_size | Size of the root volume in GB | `number` | n/a | yes |
+| ecs\_logging | Adding logging option to ECS. | `list(string)` | <pre>[<br>  "json-file",<br>  "awslogs",<br>  "gelf",<br>  "syslog"<br>]</pre> | no |
+| environment | The name of the environment | `string` | n/a | yes |
+| fleet\_config | n/a | `map(string)` | n/a | yes |
+| iam\_instance\_profile\_id | The id of the instance profile that should be used for the instances | `string` | n/a | yes |
+| instance\_override | n/a | <pre>list(object({<br>    instance_type     = string<br>    weighted_capacity = number<br>  }))</pre> | n/a | yes |
+| key\_name | SSH key name to be used | `string` | n/a | yes |
+| launch\_template\_event\_emitter\_role | IAM role to assume while emitting launch template changes | `string` | n/a | yes |
+| max\_size | Maximum size of the nodes in the cluster | `number` | `1` | no |
+| min\_size | Minimum size of the nodes in the cluster | `number` | `10` | no |
+| region | AWS\_REGION to emit cloudwatch event for updating launch configuration | `string` | n/a | yes |
+| scale\_out | Scale out type. Defaults to MemoryReservation and threshold of 65% | `map(string)` | <pre>{<br>  "adjustment": 1,<br>  "cooldown": 300,<br>  "evaluation_periods": 2,<br>  "threshold": 65,<br>  "type": "MemoryReservation"<br>}</pre> | no |
+| security\_group\_ids | The list of security groups to place the instances in | `list(string)` | n/a | yes |
+| subnet\_ids | The list of subnets to place the instances in | `list(string)` | n/a | yes |
+| vpc\_id | The VPC id | `string` | n/a | yes |
+
+## Outputs
+
+No output.

ecs-cluster/main.tf

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+locals {
+  name = "${var.cluster}-${var.cluster_uid}"
+}
+
+resource "aws_launch_template" "ecs-lc" {
+  name_prefix            = local.name
+  description            = "ECS launch template for ${local.name}"
+  image_id               = var.aws_ami
+  vpc_security_group_ids = var.security_group_ids
+  user_data              = base64encode(data.template_file.user_data.rendered)
+  key_name               = var.key_name
+  instance_type          = var.instance_override[0].instance_type
+
+  iam_instance_profile {
+    name = var.iam_instance_profile_id
+  }
+
+  block_device_mappings {
+    device_name = "/dev/xvda"
+
+    ebs {
+      volume_type           = "gp2"
+      volume_size           = var.ebs_root_volume_size
+      delete_on_termination = true
+    }
+  }
+
+  disable_api_termination              = false
+  instance_initiated_shutdown_behavior = "terminate"
+
+  lifecycle {
+    create_before_destroy = true
+  }
+
+  tag_specifications {
+    resource_type = "volume"
+
+    tags = {
+      Name        = var.cluster
+      Environment = var.environment
+    }
+  }
+}
+
+resource "aws_autoscaling_group" "ecs-asg" {
+  name_prefix         = local.name
+  max_size            = var.max_size
+  min_size            = var.min_size
+  desired_capacity    = var.desired_capacity
+  force_delete        = true
+  vpc_zone_identifier = var.subnet_ids
+  capacity_rebalance  = true
+
+  mixed_instances_policy {
+    instances_distribution {
+      on_demand_percentage_above_base_capacity = var.fleet_config.on_demand_percentage_above_base_capacity
+      spot_max_price                           = lookup(var.fleet_config, "spot_max_price", "")
+      spot_allocation_strategy                 = "capacity-optimized"
+      spot_instance_pools                      = 0
+    }
+
+    launch_template {
+      launch_template_specification {
+        launch_template_id = aws_launch_template.ecs-lc.id
+        version            = aws_launch_template.ecs-lc.latest_version
+      }
+
+      dynamic "override" {
+        for_each = var.instance_override
+        content {
+          instance_type     = override.value.instance_type
+          weighted_capacity = override.value.weighted_capacity
+        }
+      }
+    }
+  }
+
+  tag {
+    key                 = "Name"
+    value               = var.cluster
+    propagate_at_launch = "true"
+  }
+
+  tag {
+    key                 = "Environment"
+    value               = var.environment
+    propagate_at_launch = "true"
+  }
+
+  tag {
+    key                 = "DependsId"
+    value               = var.depends_id
+    propagate_at_launch = "false"
+  }
+
+  lifecycle {
+    # prevent_destroy = true
+    # ignore_changes = [
+    #   desired_capacity,
+    #   max_size,
+    # ]
+  }
+}
+
+resource "aws_autoscaling_policy" "scale-out" {
+  name                   = "${local.name}-scale-out"
+  autoscaling_group_name = aws_autoscaling_group.ecs-asg.name
+  adjustment_type        = "ChangeInCapacity"
+  policy_type            = "SimpleScaling"
+  cooldown               = var.scale_out.cooldown
+  scaling_adjustment     = var.scale_out.adjustment
+}
+
+# Used magic formula
+resource "aws_cloudwatch_metric_alarm" "scale-out" {
+  alarm_name          = "${local.name}-scale-out"
+  namespace           = "AWS/ECS"
+  metric_name         = var.scale_out.type
+  threshold           = var.scale_out.threshold
+  period              = "60"
+  evaluation_periods  = var.scale_out.evaluation_periods
+  statistic           = "Average"
+  comparison_operator = "GreaterThanOrEqualToThreshold"
+
+  dimensions = {
+    ClusterName = var.cluster
+  }
+
+  alarm_description = "Scale out ECS cluster"
+  alarm_actions     = [aws_autoscaling_policy.scale-out.arn]
+}
+
+data "template_file" "user_data" {
+  template = file("${path.module}/templates/user_data.sh")
+
+  vars = {
+    ecs_logging     = jsonencode(var.ecs_logging)
+    cluster_name    = var.cluster
+    attributes      = jsonencode(var.cluster_attributes)
+    custom_userdata = var.custom_userdata
+  }
+}
+
+resource "null_resource" "launch-config-update" {
+  provisioner "local-exec" {
+    command = "AWS_METADATA_SERVICE_TIMEOUT=10 AWS_METADATA_SERVICE_NUM_ATTEMPTS=18 python3 ${path.module}/scripts/emit_launchconfig_event.py --role_to_assume ${var.launch_template_event_emitter_role} --environment ${var.environment} --region ${var.region} --launch_template_id ${aws_launch_template.ecs-lc.id} --launch_template_latest_version ${aws_launch_template.ecs-lc.latest_version} --autoscaling_group_name ${aws_autoscaling_group.ecs-asg.name} --cluster ${var.cluster}"
+  }
+
+  triggers = {
+    launchTemplateId      = aws_launch_template.ecs-lc.id
+    launchTemplateVersion = aws_launch_template.ecs-lc.latest_version
+  }
+}
+

ecs-cluster/scripts/emit_launchconfig_event.py

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+#!/usr/bin/env python
+"""
+  Emit terraform cloudwatch event on launch configuration changes
+"""
+
+import argparse
+import boto3
+import json
+import logging as log
+import os
+import sys
+
+ROOT_DIR = os.path.join(os.path.dirname(__file__), "../../../lib/")
+sys.path.append(ROOT_DIR)
+
+from assume_role import get_temporary_credentials
+from functools import partial
+
+
+def color(text, code='37', bold=False):
+  """
+    colorful logging
+    """
+  if bold:
+    code = "1;%s" % code
+  return "\033[%sm%s\033[0m" % (code, text)
+
+
+red = partial(color, code='31')
+green = partial(color, code='32')
+yellow = partial(color, code='33')
+
+
+def err(message):
+  """
+    error logging
+    """
+  log.error(red(message))
+  exit(1)
+
+
+def info(message):
+  """
+    info logging
+    """
+  log.info(green(message))
+
+
+def warn(message):
+  """
+    warn logging
+    """
+  log.warn(yellow(message))
+
+
+def parse_cli():
+  """
+    Parse CLI options
+    """
+  parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+  parser.add_argument('--role_to_assume', type=str, help='AWS IAM role to assume', required=True)
+  parser.add_argument('--region', type=str, help='AWS region', required=True)
+  parser.add_argument('--launch_template_id', type=str, help='AWS launch template id', required=True)
+  parser.add_argument('--launch_template_latest_version', type=str, help='AWS launch template version', required=True)
+  parser.add_argument('--autoscaling_group_name', type=str, help='AWS autoscaling group name', required=True)
+  parser.add_argument('--cluster', type=str, help='AWS ECS cluster name', required=True)
+  parser.add_argument('--environment', type=str, help='Environment we are dealing with', required=True)
+  parser.add_argument('--log_level', default='INFO', help='logging level', choices=['INFO', 'ERROR', 'WARN'])
+
+  return parser.parse_args()
+
+
+def apply_cli_options(args):
+  """
+    Apply CLI options
+    """
+  log.basicConfig(level=args.log_level, format='[%(asctime)s] %(levelname)s: %(message)s', datefmt='%Y-%m-%d %H:%M:%S')
+
+  return args
+
+
+def emit_cloudwatch_event(args):
+  """
+    Emit cloudwatch event
+    """
+
+  credentials = get_temporary_credentials(role_to_assume=args.role_to_assume,
+                                          region=args.region,
+                                          session_name=args.cluster + args.launch_template_id +
+                                          args.launch_template_latest_version)
+
+  client = boto3.client('events',
+                        region_name=args.region,
+                        aws_access_key_id=credentials["AccessKeyId"],
+                        aws_secret_access_key=credentials["SecretAccessKey"],
+                        aws_session_token=credentials["SessionToken"])
+
+  # AWS API resonses don't have consistent naming schema
+  # This event mimicks their response style
+  event = {
+      'Source':
+          'comtravo.terraform.{}'.format(args.environment),
+      'Resources': [args.launch_template_id, args.launch_template_latest_version],
+      'DetailType':
+          'ECS Launch Configuration Change',
+      'Detail':
+          json.dumps({
+              'autoscalingGroupName': args.autoscaling_group_name,
+              'clusterArn': args.cluster,
+              'agentConnected': False,
+              'status': 'ACTIVE'
+          })
+  }
+
+  try:
+    res = client.put_events(Entries=[event])
+    if res['FailedEntryCount'] != 0:
+      err('Error emitting cloudwatch event: {}. Got response: {}'.format(event, res))
+    else:
+      info('Event: {} emitted successfully!'.format(event))
+      info('Event emitted successfully! with response: {}'.format(res))
+  except Exception as _e:
+    err('Error emitting cloudwatch event {}. Got error {}'.format(event, _e))
+
+
+def main():
+  """
+    main
+    """
+  args = parse_cli()
+  args = apply_cli_options(args)
+  emit_cloudwatch_event(args)
+
+
+if __name__ == "__main__":
+  main()