Automatic Registration of Clients Created by Terraform

New clients created by Terraform can be automatically registered to Uyuni. Registration can be achieved in two ways:

  • cloud-init based registration

  • remote execution provisioner based registration

1. cloud-init Based Client Registration

Registering by leveraging cloud-init is the preferred way of automatic registering of the newly created virtual machines. This solution avoids configuring an SSH connection to the host. It can also be used regardless of the tool used for client creation.

User can pass the set of user data when deploying the image with Terraform, to automatically register the machine to Uyuni. user_data is run only once at bootstrap, and only the first time the machine is started.

Before using cloud-init to register clients, the user must configure:

The following command will download the bootstrap script and register the new machine when it is created. It should be added to the cloud-init configuration:

curl -s http://hub-server.tf.local/pub/bootstrap/bootstrap-default.sh | bash -s

Any time user_data is updated to change the provisioning, Terraform will destroy and then recreate the machines with a new IP, etc.

For more information about cloud-init on AWS, see https://registry.terraform.io/providers/hashicorp/template/latest/docs/data-sources/cloudinit_config.

For a cloud-init example, see https://registry.terraform.io/providers/hashicorp/cloudinit/latest/docs/data-sources/cloudinit_config#example-usage.

2. remote-exec Provisioner Based Registration

The second solution for automatic registering of the newly created virtual machines uses Terraform’s remote-exec provisioner.

remote-exec provisioner interacts with the newly created machines. It opens an SSH connection and can run commands on that machine.

When using remote-exec provisioner to register clients, the user must ensure that the machine running Terraform will have access to the new virtual machine after its creation.

The remaining requirements are the same as when using cloud-init Based Client Registration:

The following command will download the bootstrap script and register the new machine when it is created. It should be defined as the remote command to run:

curl -s http://hub-server.tf.local/pub/bootstrap/bootstrap-default.sh | bash -s

For more information about remote-exec provisioner, see https://www.terraform.io/docs/provisioners/remote-exec.html.