Merged in dev/rich/modify-ec2-ebs-disk-size-2021.03.05 (pull request e…

…lastic#70)

Ability to increase the EBS disk size on terraform created stacks

* This commit is for https://engageli.atlassian.net/browse/MPC-1457,
and the JIRA has a confluence page linked that provides additional
information.

It adds the capability to increase the EBS disk size on
terraform created stacks for these instance roles:
* EMS
* Engageli
* Merger
* Recorder

Here is the required variables in the tfvars to enable this
feature, and the values are in Gb.  The value of `8` is the
default, so adding this section as is, will not make any
changes to the instances:

```
ebs_root_volume_size = {
  "engageli" = 8
  "ems" = 8
  "merger" = 8
  "recorder" = 8
}
```

For the variables it uses the new map format, since the existing
map has been deprecated:
  https://www.terraform.io/docs/language/functions/map.html
modified:   aws/ams-cluster-v1-tf/ems.tf
modified:   aws/ams-cluster-v1-tf/main.tf
modified:   aws/ams-cluster-v1-tf/variables.tf

Approved-by: Gideon Avida

aws/ams-cluster-v1-tf/ems.tf

@@ -89,6 +89,9 @@ resource "aws_instance" "ems" {
     aws_security_group.ems.id
   ]
   subnet_id = aws_subnet.subnets[0].id # FIXME for cluster v2
+  root_block_device {
+    volume_size = var.ebs_root_volume_size.ems
+  }
   tags = {
     Name      = "tf-${var.stack_name}-ems"
     Role      = "ems"

aws/ams-cluster-v1-tf/main.tf

@@ -469,6 +469,9 @@ resource "aws_instance" "engageli" {
     aws_security_group.redis_clients.id
   ]
   subnet_id = aws_subnet.subnets[0].id # FIXME for cluster v2
+  root_block_device {
+    volume_size = var.ebs_root_volume_size.engageli
+  }
   tags = {
     Name        = "tf-${var.stack_name}-engageli"
     Role        = "engageli-api"
@@ -509,6 +512,9 @@ resource "aws_instance" "merger" {
     aws_security_group.redis_clients.id
   ]
   subnet_id = aws_subnet.subnets[0].id # FIXME for cluster v2
+  root_block_device {
+    volume_size = var.ebs_root_volume_size.merger
+  }
   tags = {
     Name              = "tf-${var.stack_name}-merger"
     Role              = "merger"
@@ -532,6 +538,9 @@ resource "aws_instance" "recorder" {
     aws_security_group.redis_clients.id
   ]
   subnet_id = aws_subnet.subnets[0].id # FIXME for cluster v2
+  root_block_device {
+    volume_size = var.ebs_root_volume_size.recorder
+  }
   tags = {
     Name                = "tf-${var.stack_name}-recorder"
     Role                = "recorder"
@@ -640,21 +649,21 @@ resource "aws_lb_target_group_attachment" "engageli" {
 }
 
 resource "aws_lb_target_group" "ems" {
-  count                = var.num_ems
+  count       = var.num_ems
   name        = "tf-${var.stack_name}-ems-tg"
   port        = 443
   protocol    = "HTTPS"
   vpc_id      = aws_vpc.main.id
   target_type = "instance"
   health_check {
-    enabled = true # Required by AWS: "Health check enabled must be true for target groups with target type 'instance'"
+    enabled = true        # Required by AWS: "Health check enabled must be true for target groups with target type 'instance'"
     path    = "/ems/ping" # FIXME
     matcher = 200
   }
 }
 
 resource "aws_lb_target_group_attachment" "ems" {
-  count                = var.num_ems
+  count            = var.num_ems
   target_group_arn = aws_lb_target_group.ems[count.index].arn
   target_id        = aws_instance.ems[count.index].id
   port             = 443

aws/ams-cluster-v1-tf/variables.tf

@@ -167,6 +167,16 @@ variable "instance_types" {
   }
 }
 
+variable "ebs_root_volume_size" {
+  description = "Size of the root EBS volume in gibibytes (GiB)"
+  default = {
+    "ems"      = 8
+    "engageli" = 8
+    "recorder" = 8
+    "merger"   = 8
+  }
+}
+
 variable "concurrent_mergers" {
   description = "Number of concurrent merger workers in a dequeue node"
   type        = number