OCI Resource Management: How to Handle Resource Dependencies in Terraform for Complex Architectures
I'm prototyping a solution and This might be a silly question, but I'm working on a personal project and I'm working on a complex infrastructure deployment on OCI using Terraform, specifically with version 1.3.6 of the OCI provider..... I am working with issues with resource dependencies that result in execution failures and unexpected behaviors during deployment. I have a setup that includes multiple networking components, compute instances, and databases. For instance, I'm trying to create a VCN, subnets, and then instances that rely on the subnet being created first. Here’s a snippet of my Terraform configuration: ```hcl resource "oci_core_virtual_network" "my_vcn" { compartment_id = var.compartment_id display_name = "my-vcn" cidr_block = "10.0.0.0/16" } resource "oci_core_subnet" "my_subnet" { compartment_id = var.compartment_id display_name = "my-subnet" vcn_id = oci_core_virtual_network.my_vcn.id cidr_block = "10.0.1.0/24" availability_domain = var.availability_domain } resource "oci_core_instance" "my_instance" { compartment_id = var.compartment_id display_name = "my-instance" availability_domain = var.availability_domain shape = "VM.Standard2.1" source_details { source_type = "image" source_id = var.image_id } create_vnic_details { subnet_id = oci_core_subnet.my_subnet.id } } ``` Despite explicitly referencing `oci_core_virtual_network.my_vcn.id` and `oci_core_subnet.my_subnet.id`, the Terraform apply command often throws the following behavior: ``` behavior: behavior creating instance: InvalidRequest: A VNIC must be associated with a valid subnet. ``` I've attempted adding explicit `depends_on` attributes, but that doesn't seem to help. Here’s an example: ```hcl resource "oci_core_instance" "my_instance" { depends_on = [oci_core_subnet.my_subnet] # other configurations... } ``` I’ve also checked that the subnet ID is being resolved correctly by outputting its value, and it appears to be correct. However, Terraform sometimes tries to create the instance before the subnet is fully created, leading to race conditions. I believe it might be related to how Terraform handles resource dependencies internally with its graph. Has anyone faced a similar situation and can suggest a reliable way to manage these resource dependencies in Terraform for OCI deployments? Any best practices or insights on resource graph handling would be greatly appreciated. My development environment is macOS. I'd really appreciate any guidance on this. I'm working on a web app that needs to handle this. For context: I'm using Hcl on Ubuntu 22.04. What would be the recommended way to handle this? I'm coming from a different tech stack and learning Hcl. Am I approaching this the right way? For context: I'm using Hcl on Windows 11. What's the best practice here?