Unable to propagate default_tags through asg/launch_template to instances/volumes

[tschaffer-smart]

I am unable to get default_tags to propagate into my ASG's instances and volumes.

An ASG can propagate, but it requires explicitly setting the tag and adding "propagate_at_launch = true". The alternative is defining it in the tag_specifications in the launch_template, but that one is not inheriting the values. I have tried the default of not defining tags_specifications blocks, and also defined a "simple" form, where I set only one dummy tag to see if it would still pull the default tags.

I would accept if all that was necessary was to define the stanza to force it through, but ideally this shouldn't be necessary - since we defined at the provider level that we want everything tagged.

example for minimal spec for launch_template.tf

tag_specifications {
resource_type = "instance"
}

[anGie44]

Hi @tschaffer-smart , thank you for raising this issue. For resources that support tags, default_tags are only propagated with the root-level tags configuration in mind. Since the tags in reference are nested within the tag_specifications block, support is not yet available; nevertheless, we'll take note of this use case as it relates to #19188

[ivankatliarchuk]

tags_specifications block does not inherit default_tags. Any plans to support this use case?

[villapx-path]

This doesn't solve the "missing" feature, but you can achieve the desired behavior by replacing the provider.aws.default_tags block with a (local) variable:

locals {
  default_tags = {
    SomeDefaultTag = "some value"
  }
}

provider "aws" {
  default_tags {
    tags = local.default_tags
  }
}

resource "aws_launch_template" "my_launch_template" {
  name = "mine"
  tag_specifications {
    resource_type = "instance"
    tags = merge(
      {
        LaunchTemplateSpecificTag = "Some tag to be applied to every instance"
      },
      local.default_tags
    )
  }
}