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05-Terraform-Loops-MetaArguments-SplatOperator/05-02-MetaArgument-for_each/README.md

@@ -37,13 +37,26 @@ resource "aws_instance" "myec2vm" {
   user_data = file("${path.module}/app1-install.sh")
   key_name = var.instance_keypair
   vpc_security_group_ids = [ aws_security_group.vpc-ssh.id, aws_security_group.vpc-web.id   ]
-  # Create EC2 Instance in all Availabilty Zones of a VPC  
+
+  # Create EC2 Instance in all Availabilty Zones of a VPC 
+
   for_each = toset(data.aws_availability_zones.my_azones.names)
-  availability_zone = each.key # You can also use each.value because for list items each.key == each.value
+
+  #toset: converts list into set, In set, removes duplicates,
+  #changes either string or int to highest number of arguments form ( if more strings are present in the list, 
+  #it will convert number as well to string; arranges in order.
+
+  availability_zone = each.key  # You can also use each.value because for list items each.key == each.value
+
   tags = {
     "Name" = "For-Each-Demo-${each.key}"
   }
 }
+
+## output: Will create instances in each availability zones and with name tag given and each.key,  for every instance it will have name as, For-Each-Demo-ap-south-1, For-Each-Demo-ap-south-2....
+## ** Note: Both meta-arguments cannot be used in one resource block,  if for_each is used then count or any other meta-argument cannot be used.**
+
+
 ```
 
 ## Step-04: c6-outputs.tf
@@ -122,4 +135,4 @@ rm -rf terraform.tfstate*
 - [Data Source: aws_availability_zones](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/availability_zones)
 - [for_each Meta-Argument](https://www.terraform.io/docs/language/meta-arguments/for_each.html)
 - [tomap Function](https://www.terraform.io/docs/language/functions/tomap.html)
-- [toset Function](https://www.terraform.io/docs/language/functions/toset.html)
+- [toset Function](https://www.terraform.io/docs/language/functions/toset.html)

05-Terraform-Loops-MetaArguments-SplatOperator/05-02-MetaArgument-for_each/terraform-manifests/c5-ec2instance.tf

@@ -17,6 +17,7 @@ resource "aws_instance" "myec2vm" {
   # Create EC2 Instance in all Availabilty Zones of a VPC  
   for_each = toset(data.aws_availability_zones.my_azones.names)
   availability_zone = each.key  # You can also use each.value because for list items each.key == each.value
+  # for map it should have value.
   tags = {
     "Name" = "for_each-Demo-${each.value}"
   }

05-Terraform-Loops-MetaArguments-SplatOperator/05-04-for_each-with-az-instancetype-check/terraform-manifests/c5-ec2instance.tf

@@ -6,11 +6,13 @@ resource "aws_instance" "myec2vm" {
   key_name = var.instance_keypair
   vpc_security_group_ids = [ aws_security_group.vpc-ssh.id, aws_security_group.vpc-web.id   ]
   # Create EC2 Instance in all Availabilty Zones of a VPC  
-  #for_each = toset(data.aws_availability_zones.my_azones.names)
+  # ** for_each = toset(data.aws_availability_zones.my_azones.names) **
   for_each = toset(keys({for az, details in data.aws_ec2_instance_type_offerings.my_ins_type: 
     az => details.instance_types if length(details.instance_types) != 0 }))
   availability_zone = each.key # You can also use each.value because for list items each.key == each.value
+  # But for Map, only vlaue should be given.
   tags = {
     "Name" = "For-Each-Demo-${each.key}"
   }
 }
+