Playing with Terraform graphs

Let's play around with our VPC a bit to better understand how resource dependencies are handled. Instead of adding a subnet, let's destroy the complete infrastructure we have so far and then plan creation from scratch:

$> terraform destroy$> terraform plan      # ... + aws_subnet.public
        availability_zone:       "<computed>"
        cidr_block:              "10.0.1.0/24"    map_public_ip_on_launch: "false"
        vpc_id:                  "${aws_vpc.my_vpc.id}"
    # ...

Terraform doesn't know the VPC ID yet, so it doesn't show it to you in the plan. Let's apply the template and observe the order of resource creation:

$> terraform applyaws_vpc.my_vpc: Creating...  cidr_block:                "" => "10.0.0.0/16"  default_network_acl_id:    "" => "<computed>"  default_security_group_id: "" => "<computed>"  dhcp_options_id:           "" => "<computed>"  enable_classiclink:        "" => "<computed>"  enable_dns_hostnames...