Allow a different set of tags on the instance spun up by Packer

[palladiumsai]

Description

A written overview of the feature.

Currently, the tags defined in run_tags are applied to the instance spun up by Packer. All the tags defined in run_tags are also inherited by the finished AMI. This is not always desirable, since one may want to have different set of tags on the instance for provisioning purposes. Attaching a relevant forum discussion: https://discuss.hashicorp.com/t/tags-and-run-tags/62748.

This feature addition might alleviate the pain caused in issue: #361, where the author of the issue requests for a feature to unset the run_tags on the finished AMI. This will not be a problem if the resulting AMI does not inherit them in the first place.

Potential configuration

I propose we add a new block, say run_instance_tags similar to run_volume_tags which specifies the tags to be applied to the EC2 instance spun up by Packer. This can be a template engine like other tags block.

• if run_tags and run_instance_tags are defined, only tags in run_instance_tags will be applied to the instance spun up by Packer
• if run_instance_tags is not defined, then the tags in run_tags will be applied to said EC2 instance.

Alternatively, one might decide to have another block -- say final_ami_tags which determines the set of tags on the final AMI. tags currently does this, but this does not unset the tags set using run_tags

Potential References