Terraform: Difference between revisions

There are two ways to provide your OpenStack credentials in a command-line environment: via environment variables or in a configuration file.  We'll need to use one of these methods with Terraform, described in the [[#Defining_OpenStack_provider|next section]].  Regardless of your preferred method, the OpenStack web interface offers a simple way to download credentials: once logged in, click on ''API Access'' in the navigation bar, and on that page is a drop-down menu entitled “Download OpenStack RC File”. From here you may download a <code>clouds.yaml</code> file or an RC file which can be sourced from your shell session.

First, describe the ''provider'': this is where you tell Terraform to use OpenStack, and how. On initialization the most recent version of the OpenStack provider plugin will be installed in the working directory and on subsequent Terraform operations, the included credentials will be used to connect to the specified cloud.

<blockquote>'''Important''': It is good practice to '''always''' specify flavours and images using their IDs even when Terraform supports using the name. Although the name is more readable, the ID is what actually defines the state of the resource and the ID of a given image or flavour '''will never change'''. It is possible, however, for the '''name''' to change. If a flavour or image is retired, for example, and replaced with another of the same name, the next time you run Terraform, the updated ID will be detected and Terraform will determine that you want to '''rebuild or resize the associated resource'''. This is a destructive (and reconstructive) operation.

<blockquote>'''Note''': If you’re following along (please do!), use your own values for <code>image_id</code>, <code>flavor_id</code>, and <code>key_pair</code>, or this will probably fail!