Ansible HostGroup Support

[proffalken]

At present there doesn't appear to be a way to output the data from terraform as Ansible Host Groups to allow for multiple hosts to be configured via a single play.

For example, a play that starts with "hosts: webservers" doesn't know that "aws_instance.webserver.0" should belong to the "webservers" ansible group.

It would be nice to have some way of mapping aws_instance.webserver.* to a group or similar.

[adammck]

Yes, this would be very useful, especially when multiple identical resources are created with Terraform's count parameter. They should all be returned as a single host group.

[kvz]

+1

[girvo]

+1

[afritzler]

+1

[zihaoyu]

+1

[jackspirou]

Working on a little patch with @jbehling that should help with this. You can find it here master...jackspirou:master

The idea is that metadata.groups would be string of comma separated groups that would be parsed upon the --list flag. So values like "metadata.groups": "mongosc,mongos,mongoc", might produce something like the following output:

{
  "mongoc":["10.10.10.101","10.10.10.102","10.10.10.103"],
  "mongos":["10.10.10.101","10.10.10.102","10.10.10.103"],
  "mongosc":["10.10.10.101","10.10.10.102","10.10.10.103"],
  "server.0":["10.10.10.101"],
  "server.1":["10.10.10.102"],
  "server.2":["10.10.10.103"]
}

[jackspirou]

@adammck Let me and @jbehling know what you think of PR #21 and if it helps solve this issue.

[vasiliyb]

+1

[adammck]

Please check out #22 for an implementation of this. Feedback would be very much appreciated.

[johnwards]

@adammck So glad I found this today :) I'm just doing some elasticsearch stuff with terraform and ansible so needed groups.

Works perfectly, however just an FYI from terraform that you'll need to come up with a different strategy for naming things.

Warnings:
  * aws_instance.eip-elasticsearch.2: eip-elasticsearch.2: resource name can only contain letters, numbers, dashes, and underscores.
This will be an error in Terraform 0.4
  * aws_instance.eip-elasticsearch.1: eip-elasticsearch.1: resource name can only contain letters, numbers, dashes, and underscores.
This will be an error in Terraform 0.4

[adammck]

Thanks for the heads up, @johnwards! I don't entirely understand the warning, since those resource names -- something.index -- were presumably generated by Terraform itself, via the count param. Or perhaps it's specific to your templates?

[johnwards]

Ah, so this might be my problem I guess. I directly named my ec2 instances:

resource "aws_instance" "eip-elasticsearch.1"

resource "aws_instance" "eip-elasticsearch.2"

So in this case this is my bad for not realising there is a count param and putting it in manually, but I do think that having instances of different settings (security groups, instance size etc) but in the same group is probably a valid use case and you could achieve it this way?