Terraform: Adding AWS security group forces new resource

[jmreicha]

Currently if you add a security group in AWS terraform reports the following and a new resource is forced.

security_groups.#:                         "1" => "2" (forces new resource)
security_groups.3297643359:                "sg-XXX" => "sg-XXX" (forces new resource)
security_groups.966748175:                 "" => "sg-XXX" (forces new resource)

It would be nice to be able to add a security group to a list of security groups (not changing any existing SG's) without having to recreate the server.

[arukaen]

If you are using ec2 classic then that is the only way to apply additional SGs. If you are on VPC then this is definitely a modification I would like to see to terraform since AWS VPC allows you to add/remove SGs on the fly.

[jmreicha]

Yes sorry, forgot to mention this was for a VPC.

[mitchellh]

This is another bug reported somewhere. We're close to finally fixingthis but please track that bug.

[calvn]

@mitchellh can that issue be referenced here? This bug seems to occur as of v0.6.8. I have an existing aws_instance resource with 1 security group under security_groups, and when I try to add a second one it tells be that the existing aws_instance resource will be deleted because the additional security group forces new resource.

[catsby]

Hello @cleung2010 – for instances in a VPC, use vpc_security_group_ids instead of regular security_groups. Using the vpc_ version will allow you to add/remove security groups without recreating the instance.

Thanks!

[n8gard]

Sorry for the noise, but just wanted to say thanks so much for this. I've been banging my head as all my instances have been being force-recreated. I missed it in the docs. Terraform rawks.

[harrocan]

Thanks! It helped a lot for beginner in terraform like me :)

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