How to add a new resource to an existing resource group in Terraform

Question

This would appear to be a fairly simple and basic scenario but I'm frankly at a loss on how to get around this using Terraform and would appreciate any suggestions.

The issue is this. In Azure, I have a number of resource groups, each containing a number of resources, including virtual networks, subnets, storage accounts, etc. What I would now like to do is add new resources to one or two of the resource groups. Typical example, I would like to provision a new virtual machine in each of the resource groups.

Now, so far all of the documentation and blogs I seem to come across only provide guidance on how to create resources whereby you also create a new resource group, vnet, subnet, from scratch. This is definitely not what I wish to do.

All I'm looking to do is get Terraform to add a single virtual machine to an existing resource group, going on to configure it to connect to existing networking resources such as a VNet, Subnet, etc. Any ideas?

Answer 1

If you just want to be able to reference your existing resources in your TF script, you normally would use date sources in TF to fetch their information.

So for resource group, you would use data source azurerm_resource_group , for vnet there is azurerm_virtual_network and so forth.

These data sources would allow you to only reference and get details of existing resources, not to manage them in your TF script. Thus if you would like to actually manage these resources using TF (modify, delete, etc), you would have to import them first to TF.

Answer 2

I tested for ECS by destroying the launch configuration.

terraform destroy -target module.ecs.module.ec2_alb.aws_launch_configuration.launchcfg

I recreated the launch configuration and it worked:

terraform plan -target=module.ecs.module.ec2_alb.aws_launch_configuration
terraform apply -target=module.ecs.module.ec2_alb.aws_launch_configuration

Also, you can go read more on Terraform target here: https://learn.hashicorp.com/tutorials/terraform/resource-targeting