Terraform: What are the different `terraform plan` symbol meanings?

[davidvuong]

I've been using Terraform for over 7 months and I still don't fully understand the meaning behind some of the symbols in the output of terraform plan. Parts of the documentation reference some symbols, but not all.

• + means to add
• - means to destroy
• -/+ destroy and then recreate with new changes
• ~ means to change without destroying
• <= (I'm not sure here)

Are there any others that I missed?

[apparentlymart]

Good questions all, @davidvuong! Thanks for pointing out that this isn't documented well.

For now, here they are, until we get it included in the docs better:

• + create
• - destroy
• -/+ replace (destroy and then create, or vice-versa if create-before-destroy is used)
• ~ update in-place
• <= read

The last one applies only to data resources. You won't see this one often, because whenever possible Terraform does reads during the refresh phase. You will see it, though, if you have a data resource whose configuration depends on something that we don't know yet, such as an attribute of a resource that isn't yet created. In that case, it's necessary to wait until apply time to find out the final configuration before doing the read.

[JDiPierro]

Came here searching for the meaning of <= as well. I was getting it on a template_file which seemed really strange since I hadn't edited the file. I did, however, remove a variable from the vars section that wasn't actually used in the template. I re-added it an the <= went away.

[apparentlymart]

In #15884 a symbol key was included directly into the terraform plan output, for more direct reference.

[rberlind]

Hi @apparentlymart : could we add the content about the meaning of the different symbols in plan to our official docs somewhere? Maybe under https://www.terraform.io/docs/commands/plan.html ?

[apparentlymart]

Hi @rberlind,

After we added it to the actual terraform plan output it felt redundant to also add it to the docs, since I think there's never a situation where the symbols are used in the UI without a definition alongside. Do you have a specific situation where it's important to refer to the symbols outside of the context of running terraform plan itself?

[rberlind]

I think +, -, and -/+ are clear in the plan output, but I saw <= and did not really understand it. I think adding to the docs would be useful.

[apparentlymart]

Ahh @rberlind, I think you're saying that the terse descriptions in the terraform plan output are not sufficient to fully explain what these mean, and you'd like to see a _more detailed_ description in the docs. Is that right?

[rberlind]

Yes. That is right. I would like to see the docs include all the possible output symbols and their meanings. The meanings you gave above, although terse, were basically enough, although one would probably add a few more words in official docs.

As soon as I saw "read", I then knew what the <= had meant for the resource in question.

[rberlind]

Hi @apparentlymart

Apologies. I now see that the definitions of the symbols like + and <= are at the top of the plan. I don't think I had ever noticed them before. I think I had only seen them in front of actual resources.

Since the definitions are given, I supposed they don't absolutely have to be in our docs. But if someone had time to add it there too, it would be nice.

Roger

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