for_each

https://www.terraform.io/language/meta-arguments/for_each

The for_each meta-argument accepts a map or a set of strings, and creates an instance for each item in that map or set.

Each instance has a distinct infrastructure object associated with it, and each is separately created, updated, or destroyed when the configuration is applied.

In blocks where for_each is set, an additional each object is available in expressions, so you can modify the configuration of each instance. This object has two attributes:

• each.key — The map key (or set member) corresponding to this instance.

• each.value — The map value corresponding to this instance. (If a set was provided, this is the same as each.key.)

resource "aws_vpc" "vpc2" {

  for_each = {
    private = "10.1.0.0/16"
    public  = "192.168.0.0/16"
  }
  cidr_block           = each.value
  enable_dns_hostnames = var.enable_dns_hostnames
  tags = {
    Name = "terraform-vpc-${each.key}"
  }

}

Terraform plan

$ terraform plan

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the
following symbols:
  + create

Terraform will perform the following actions:

  # aws_vpc.vpc2["private"] will be created
  + resource "aws_vpc" "vpc2" {
      + arn                                  = (known after apply)
      + cidr_block                           = "10.1.0.0/16"
      + default_network_acl_id               = (known after apply)
      + default_route_table_id               = (known after apply)
      + default_security_group_id            = (known after apply)
      + dhcp_options_id                      = (known after apply)
      + enable_classiclink                   = (known after apply)
      + enable_classiclink_dns_support       = (known after apply)
      + enable_dns_hostnames                 = true
      + enable_dns_support                   = true
      + id                                   = (known after apply)
      + instance_tenancy                     = "default"
      + ipv6_association_id                  = (known after apply)
      + ipv6_cidr_block                      = (known after apply)
      + ipv6_cidr_block_network_border_group = (known after apply)
      + main_route_table_id                  = (known after apply)
      + owner_id                             = (known after apply)
      + tags                                 = {
          + "Name" = "terraform-vpc-private"
        }
      + tags_all                             = {
          + "Name" = "terraform-vpc-private"
        }
    }

  # aws_vpc.vpc2["public"] will be created
  + resource "aws_vpc" "vpc2" {
      + arn                                  = (known after apply)
      + cidr_block                           = "192.168.0.0/16"
      + default_network_acl_id               = (known after apply)
      + default_route_table_id               = (known after apply)
      + default_security_group_id            = (known after apply)
      + dhcp_options_id                      = (known after apply)
      + enable_classiclink                   = (known after apply)
      + enable_classiclink_dns_support       = (known after apply)
      + enable_dns_hostnames                 = true
      + enable_dns_support                   = true
      + id                                   = (known after apply)
      + instance_tenancy                     = "default"
      + ipv6_association_id                  = (known after apply)
      + ipv6_cidr_block                      = (known after apply)
      + ipv6_cidr_block_network_border_group = (known after apply)
      + main_route_table_id                  = (known after apply)
      + owner_id                             = (known after apply)
      + tags                                 = {
          + "Name" = "terraform-vpc-public"
        }
      + tags_all                             = {
          + "Name" = "terraform-vpc-public"
        }
    }

Plan: 2 to add, 0 to change, 0 to destroy.

───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

Note: You didn't use the -out option to save this plan, so Terraform can't guarantee to take exactly these actions if you run
"terraform apply" now.