Merge pull request #6 from skyscrapers/bluegreen_deployscript

add deployment script and documentation

README.md

@@ -55,3 +55,55 @@ module "cpu-scaling" {
   autoscaling_group_name = ["my_asg_name1","my_asg_name2"]
 }
 ```
+
+## Blue-green deployments
+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 = "${module.<blue-green-module-name>.blue_asg_id}"
+}
+
+output "blue_asg_id" {
+  value =  "${module.<blue-green-module-name>.blue_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. After that you can execute the blue-green script.
+```
+./bluegreen.py -f stacks/test/application -a ami-xxxx -c apply -t 500
+```

bluegreen.py

@@ -0,0 +1,245 @@
+#!/usr/bin/env python
+
+import boto3
+import getopt
+import sys
+import subprocess
+import time
+
+def main(argv):
+    helptext = 'bluegreen.py -f <path to terraform project> -a <ami> -c <command> -t <timeout>'
+
+    try:
+        opts, args = getopt.getopt(argv,"hf:a:c:t:",["folder=","ami=","command=", "timeout="])
+    except getopt.GetoptError:
+        print helptext
+        sys.exit(2)
+
+    if opts:
+        for opt, arg in opts:
+            if opt == '-h':
+                print helptext
+                sys.exit(2)
+            elif opt in ("-f", "--folder"):
+                projectPath = arg
+            elif opt in ("-a", "--ami"):
+                ami = arg
+            elif opt in ("-c", "--command"):
+                command = arg
+            elif opt in ("-t", "--timeout"):
+                maxTimeout = int(arg)
+    else:
+        print helptext
+        sys.exit(2)
+
+    if 'command' not in locals():
+        command = 'plan'
+
+    if 'maxTimeout' not in locals():
+        maxTimeout = 200
+
+    if 'projectPath' not in locals():
+        print 'Please give your folder path of your Terraform project'
+        print helptext
+        sys.exit(2)
+
+    if 'ami' not in locals():
+        print 'Please give a new AMI as argument'
+        print helptext
+        sys.exit(2)
+
+    # Retrieve autoscaling group names
+    agBlue = getTerraformOutput(projectPath, 'blue_asg_id')
+    agGreen = getTerraformOutput(projectPath, 'green_asg_id')
+
+    # Retrieve autoscaling groups information
+    info = getAutoscalingInfo(agBlue, agGreen)
+
+    # Determine the active autoscaling group
+    active = getActive(info)
+
+    # Bring up the not active autoscaling group with the new AMI
+    desiredInstanceCount = newAutoscaling(info, active, ami, command, projectPath)
+
+    # Retieve all ELBs annd ALBs
+    elbs = getLoadbalancers(info, 'elb')
+    albs = getLoadbalancers(info, 'alb')
+
+    # Retrieve autoscaling groups information (we need to do this again because the launchconig has changed and we need this in a later phase)
+    info = getAutoscalingInfo(agBlue, agGreen)
+
+    if command == 'apply':
+        print 'Waiting for 30 seconds to get autoscaling status'
+        time.sleep(30)
+        timeout = 30
+        while checkScalingStatus(elbs, albs, desiredInstanceCount) != True:
+            if timeout > maxTimeout:
+                print 'Roling back'
+                rollbackAutoscaling(info, active, ami, command, projectPath)
+                sys.exit(2)
+
+            print 'Waiting for 10 seconds to get autoscaling status'
+            time.sleep(10)
+            timeout += 10
+
+        print 'We can stop the old autoscaling now'
+        oldAutoscaling(info, active, ami, command, projectPath)
+
+def getTerraformOutput (projectPath, output):
+    process = subprocess.Popen('terraform output ' + output, shell=True, cwd=projectPath, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    output = process.communicate()[0].rstrip()
+    return output
+
+def getAutoscalingInfo (blue, green):
+    client = boto3.client('autoscaling')
+    response = client.describe_auto_scaling_groups(
+        AutoScalingGroupNames=[
+            blue,
+            green,
+        ],
+        MaxRecords=2
+    )
+    return response
+
+def getLoadbalancers(info, type):
+    if type == 'alb':
+        return info['AutoScalingGroups'][0]['TargetGroupARNs']
+    else:
+        return info['AutoScalingGroups'][0]['LoadBalancerNames']
+
+def getAmi (launchconfig):
+    client = boto3.client('autoscaling')
+    response = client.describe_launch_configurations(
+        LaunchConfigurationNames=[
+            launchconfig,
+        ],
+        MaxRecords=1
+    )
+    return response['LaunchConfigurations'][0]['ImageId']
+
+def getActive (info):
+    if info['AutoScalingGroups'][0]['DesiredCapacity'] > 0 and info['AutoScalingGroups'][1]['DesiredCapacity'] == 0:
+        print 'Blue is active'
+        return 0
+    elif info['AutoScalingGroups'][0]['DesiredCapacity'] == 0 and info['AutoScalingGroups'][1]['DesiredCapacity'] > 0:
+        print 'Green is active'
+        return 1
+    else:
+        print 'Both are active'
+        sys.exit(1)
+
+def newAutoscaling (info, active, ami, command, projectPath):
+    blueMin = info['AutoScalingGroups'][active]['MinSize']
+    blueMax = info['AutoScalingGroups'][active]['MaxSize']
+    blueDesired = info['AutoScalingGroups'][active]['DesiredCapacity']
+
+    greenMin = info['AutoScalingGroups'][active]['MinSize']
+    greenMax = info['AutoScalingGroups'][active]['MaxSize']
+    greenDesired = info['AutoScalingGroups'][active]['DesiredCapacity']
+
+    if active == 0:
+        blueAMI = getAmi(info['AutoScalingGroups'][active]['LaunchConfigurationName'])
+        greenAMI = ami
+    elif active == 1:
+        blueAMI = ami
+        greenAMI = getAmi(info['AutoScalingGroups'][active]['LaunchConfigurationName'])
+    else:
+        print 'No acive AMI'
+        sys.exit(1)
+
+    updateAutoscaling (command, blueMax, blueMin, blueDesired, blueAMI, greenMax, greenMin, greenDesired, greenAMI, projectPath)
+
+    # Return the amount of instances we should see in ELBs and ALBs. This is * 2 because we need to think about both autoscaling groups.
+    return info['AutoScalingGroups'][active]['DesiredCapacity'] * 2
+
+def oldAutoscaling (info, active, ami, command, projectPath):
+    blueAMI = getAmi(info['AutoScalingGroups'][0]['LaunchConfigurationName'])
+    greenAMI = getAmi(info['AutoScalingGroups'][1]['LaunchConfigurationName'])
+    if active == 0:
+        blueMin = 0
+        blueMax = 0
+        blueDesired = 0
+
+        greenMin = info['AutoScalingGroups'][active]['MinSize']
+        greenMax = info['AutoScalingGroups'][active]['MaxSize']
+        greenDesired = info['AutoScalingGroups'][active]['DesiredCapacity']
+    elif active == 1:
+        blueMin = info['AutoScalingGroups'][active]['MinSize']
+        blueMax = info['AutoScalingGroups'][active]['MaxSize']
+        blueDesired = info['AutoScalingGroups'][active]['DesiredCapacity']
+
+        greenMin = 0
+        greenMax = 0
+        greenDesired = 0
+    else:
+        print 'No acive AMI'
+        sys.exit(1)
+
+    updateAutoscaling (command, blueMax, blueMin, blueDesired, blueAMI, greenMax, greenMin, greenDesired, greenAMI, projectPath)
+
+def rollbackAutoscaling (info, active, ami, command, projectPath):
+    blueAMI = getAmi(info['AutoScalingGroups'][0]['LaunchConfigurationName'])
+    greenAMI = getAmi(info['AutoScalingGroups'][1]['LaunchConfigurationName'])
+
+
+    if active == 0:
+        blueMin = info['AutoScalingGroups'][0]['MinSize']
+        blueMax = info['AutoScalingGroups'][0]['MaxSize']
+        blueDesired = info['AutoScalingGroups'][0]['DesiredCapacity']
+
+        greenMin = 0
+        greenMax = 0
+        greenDesired = 0
+    elif active == 1:
+        greenMin = info['AutoScalingGroups'][1]['MinSize']
+        greenMax = info['AutoScalingGroups'][1]['MaxSize']
+        greenDesired = info['AutoScalingGroups'][1]['DesiredCapacity']
+
+        blueMin = 0
+        blueMax = 0
+        blueDesired = 0
+    else:
+        print 'No acive AMI'
+        sys.exit(1)
+
+    updateAutoscaling (command, blueMax, blueMin, blueDesired, blueAMI, greenMax, greenMin, greenDesired, greenAMI, projectPath)
+
+def updateAutoscaling (command, blueMax, blueMin, blueDesired, blueAMI, greenMax, greenMin, greenDesired, greenAMI, projectPath):
+    command = 'terraform ' + command + ' -var \'blue_max_size=' + str(blueMax) + '\' -var \'blue_min_size=' + str(blueMin) + '\' -var \'blue_desired_capacity=' + str(blueDesired) + '\' -var \'green_max_size=' + str(greenMax) + '\' -var \'green_min_size=' + str(greenMin) + '\' -var \'green_desired_capacity=' + str(greenDesired) + '\' -var \'green_ami=' + greenAMI + '\' -var \'blue_ami=' + blueAMI + '\''
+    print command
+    process = subprocess.Popen(command, shell=True, cwd=projectPath, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    out, err = process.communicate()
+    print 'stdoutput'
+    print out
+    print 'stderror'
+    print err
+
+def checkScalingStatus (elbs, albs, desiredInstanceCount):
+    client = boto3.client('elb')
+    for elb in elbs:
+        response = client.describe_instance_health(
+            LoadBalancerName=elb
+        )
+        if desiredInstanceCount > len(response['InstanceStates']):
+            print 'Not enough instances inside ELB, we expect ' + str(desiredInstanceCount) + ' and got ' + str(len(response['InstanceStates']))
+            return False
+        for state in response['InstanceStates']:
+            print 'ELB: ' + state['State']
+            if state['State'] != 'InService' :
+                return False
+    client = boto3.client('elbv2')
+    for alb in albs:
+        response = client.describe_target_health(
+            TargetGroupArn=alb,
+        )
+        if desiredInstanceCount > len(response['TargetHealthDescriptions']):
+            print 'Not enough instances inside ALB, we expect ' + str(desiredInstanceCount) + ' and got ' + str(len(response['TargetHealthDescriptions']))
+            return False
+        for state in response['TargetHealthDescriptions']:
+            print 'ALB: ' + state['TargetHealth']['State']
+            if state['TargetHealth']['State'] != 'healthy' :
+                return False
+    return True
+
+if __name__ == "__main__":
+   main(sys.argv[1:])