How to migrate from Chef provisioner now that it's removed

Terraform
1

Hi Team, How to use Chef cookbook here with 0.15 version? please share the steps to download cookbooks from chef-server and install them on AWS instance. I am using provisioner “chef” in resource “aws_instance” " " { }, but failing with “chef” removed in this version. Then how i can download my cookbook from chef-server and how I can run my receipt with terraform 0.15

2

Hi @gurrambalakrushna,

There are a few different ways to get this done. If you are using a Linux image which runs cloud-init at boot (most “official” Linux distribution images do) then I would suggest trying cloud-init’s chef module, which can install and run Chef in a similar way than Terraform’s old provisioner would’ve, but without any need for Terraform to SSH into the system to run it.

You can pass a configuration to cloud-init using the user_data argument for aws_instance. For example:

resource "aws_instance" "example" {
  # ...

  user_data = <<-EOT
    #cloud-config
    ${yamlencode({
      chef = {
        server_url = "https://chef.example.com:4000"
        directories = [
          "/etc/chef",
          "/var/log/chef",
        ]
        validation_cert = "system"
        install_type    = "omnibus"
        run_list = [
          "recipe[apache2]",
          "role[db]",
        ]
        exec = true
        # ...
      }
    })}
  EOT
}

My example above is using Terraform’s yamlencode option to produce YAML configuration for cloud-config from a Terraform data structure. The arguments I used above are just examples I took from the example in the cloud-init Chef module documentation; you can see what they all mean and what other options are available in the cloud-init documentation.

Cloud-init is piece of software that typically runs early in the boot process for an EC2 instance whose AMI includes it. Cloud-init will use the EC2 metadata API to retrieve your user_data string, parse it, and then take the actions you’ve described while the system is booting. This means that the cloud-init actions will happen far sooner in the boot process than a Terraform provisioner could, because they can run before an SSH server is even running. That’s one of the reasons why provisioners are a last resort.