terraform-bluegreen

Terraform module to setup blue / green deployments

##blue-green

Variables

See the blue-green/variables.tf file.

Outputs

• blue_asg_id: (Number) blue autoscaling group id
• green_asg_id: (Number) green autoscaling group id

Example

module "bluegreen" {
  source = "github.com/skyscrapers/terraform-bluegreen//blue-green"
  project = "example"
  name = "app"
  environment = "production"
  blue_ami = "ami-blabla"
  green_ami = "ami-blabla"
  instance_type = "t2.micro"
  loadbalancers = []
  blue_max_size = "5"
  blue_min_size = "2"
  blue_desired_capacity = "2"
  green_max_size = "0"
  green_min_size = "0"
  green_desired_capacity = "0"
  security_groups = []
}

scaling

Terraform module to setup alarms and autoscaling triggers for autoscaling

Variables

Name	Description	Type	Default	Required
adjustment_down	The number of instances to remove when the alarm is triggered (the value has to be negative)	string	"-1"	no
adjustment_type	What typ of adjustment needs to happen	string	"ChangeInCapacity"	no
adjustment_up	The number of instances to add when the alarm is triggered	string	"1"	no
autoscaling_group_name	The name of the AS group this config needs to be applied	list	n/a	yes
cooldown_down	The amount of time, in seconds, after a scaling activity completes and before the next scaling activity can start.	string	"600"	no
cooldown_up	The amount of time, in seconds, after a scaling activity completes and before the next scaling activity can start.	string	"300"	no
dimension_name		string	"AutoScalingGroupName"	no
dimension_value		string	"false"	no
environment	Environment to deploy on	string	n/a	yes
evaluation_periods	the number of samples to evaluate	string	"4"	no
metric_name	The metric the scaling is based upon	string	"CPUUtilization"	no
name	Name of the stack	string	n/a	yes
namespace	the namespace of the cloudwatch metric	string	"AWS/EC2"	no
num_asg	the number of autoscaling groups passed	string	"2"	no
period_down	he period in seconds over which the selected metric statistic is applied.	string	"120"	no
period_up	he period in seconds over which the selected metric statistic is applied.	string	"60"	no
policy_type	The policy type, either SimpleScaling or StepScaling	string	"SimpleScaling"	no
project	Project name to use	string	n/a	yes
statistic	The statistic to apply to the alarm's associated metric. Either of the following is supported:	string	"Average"	no
threshold_down	The metric value to scale down	string	"30"	no
threshold_up	The metric value to scale up	string	"80"	no

Outputs

/

Example

module "scaling" {
  source = "github.com/skyscrapers/terraform-bluegreen//scaling"
  project = "example"
  name = "app"
  environment = "production"
  autoscaling_group_name = ["my_asg_name1","my_asg_name2"]
}

Blue-green deployments

The bluegreen.py script performs a bluegreen deployment of the selected terraform stack. It only works with Python 2.7. The blue-green deployment script expects certain inputs and outputs in the Terraform project you want to deploy in a blue-green fashion.

Required outputs:

output "blue_asg_id" {
  value = "${module.<blue-green-module-name>.blue_asg_id}"
}

output "green_asg_id" {
  value = "${module.<blue-green-module-name>.green_asg_id}"
}

Required variables:

variable "blue_max_size" {
  description = "max instances blue"
}

variable "blue_min_size" {
  description = "min instances blue"
}

variable "blue_desired_capacity" {
  description = "desired instances blue"
}

variable "green_max_size" {
  description = "max instances green"
}

variable "green_min_size" {
  description = "min instances green"
}

variable "green_desired_capacity" {
  description = "desired instances green"
}

variable "blue_ami" {
  description = "blue ami"
}

variable "green_ami" {
  description = "green ami"
}

These input variables need to be assigned to your module. Make sure you do a terraform refresh to be sure that the terraform outputs are saved in the Terraform state file.

Usage

First you need to install the requirements:

pip install -r requirements.txt

Run ./bluegreen.py --help to see the available options.

Example:

./bluegreen.py -f stacks/test/application -a ami-xxxx -c apply -t 500