Terraform: docs: Add example S3 locking config with DynamoDb table

[catsby]

The S3 Backend docs mention that locking can be done with a DynamoDB table, but we don't provide any example of how to do so:

• https://www.terraform.io/docs/backends/types/s3.html

If possible we should add the full example config, right above configuration:

• https://github.com/hashicorp/terraform/blame/master/website/source/docs/backends/types/s3.html.md#L74

[kl-cheng]

I am creating table terraform_states in DynamoDB, stumbled on "primary key". Anyone can provide an example on how to create dynamoDB table???

[podwhitehawk]

@kl-cheng, check this comment:
https://github.com/hashicorp/terraform/issues/12877#issuecomment-289920798

[davidkern]

It is a year and a half later, and nothing has been added to the documentation. When you create a DynamoDB table, you are required to specify the hash key, and the only documentation of this is in a comment in a ticket in github.

In the documentation for the S3 backend, there is a statement: "... which can be enabled by setting the dynamodb_table field to an existing DynamoDB table name." Is it really so difficult not to add just a few more words there to specify the requirements of this table so the documentation is actually useful?

Did this fall through the cracks? Documentation for terraform is generally top-notch, but omissions like this are paper-cuts that waste time trying to use the tool.

[rpoitras]

In the Configuration Variables section there is this:

_dynamodb_table - (Optional) The name of a DynamoDB table to use for state locking and consistency. The table must have a primary key named LockID. If not present, locking will be disabled._

I didn't notice it at first ... but seems clear enough???

[davidkern]

Yup, at the time lock_table was the configuration option and the requirements for that table were not documented. However, now that is deprecated in favor of dynamodb_table, and appears documentation has been added to clarify. Also seems clear to me how to use it, so this issue is probably resolvable?

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