terraform plan states no change yet terraform apply destoryed all instances after subnet id change.

[rodrickbrown]

I made a simple subnet-id change in my configuration

After running terraform plan I noticed the following -- "Not sure what forces new resource means"
subnet_id: "subnet-5632b421" => "subnet-38da1561" (forces new resource)

I wasn't too worried because terraform plan showed the following output --
Plan: 0 to add, 24 to change, 0 to destroy.

After running terraform apply -- TF destroyed all my EC2 instances in this resource.
aws_instance.prod-mesos-master.0: Destroying...
aws_instance.prod-mesos-slave.2: Destroying...
aws_instance.prod-mesos-master.1: Destroying...
aws_instance.prod-mesos-master.2: Destroying...
aws_instance.prod-mesos-slave.3: Destroying...
aws_instance.prod-mesos-slave.4: Destroying...
aws_instance.prod-mesos-slave.0: Destroying...
aws_instance.prod-mesos-slave.1: Destroying...

The output when it was completed was --
Apply complete! Resources: 8 added, 16 changed, 8 destroyed.

I'm using Terraform v0.6.1

[semarj]

"forces new resource" means that it is going to have to delete the resource that had this attribute change and recreate it. I agree that it is confusing that the Plan: line doesn't match up to the Resources: line.

[apparentlymart]

Yeah, it looks like the bug is that the plan summary doesn't correctly handle the "forces new resource" items.

From looking at the code it seems like this is being done intentionally, by adding together the count that will be modified and the count that will be replaced. It looks like this would be a pretty easy change to make it behave more like the apply summary, assuming there isn't a good reason why it's the way it is now.

[ghost]

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