Explain the 'userData' property in hcloudServer

Question

Pulumi · Accepted Answer

The `userData` property that you can set in an 'hcloudServer' resource is a string containing 'cloud-init' data to initialize the server.

Cloud-init is a way to provide custom configuration to a cloud instance immediately upon boot. It's a versatile tool that supports a wide range of formats for providing user data, like as YAML or as shell scripts to execute at boot.

Here is an example of initializing an 'hcloudServer' with user data:

```python
import pulumi
import pulumi_hcloud as hcloud

# Initialize a server
my_server = hcloud.Server("myServer",
    image="debian-11",
    name="myServer",
    server_type="cx11",
    user_data="""
#cloud-config
package_upgrade: true
package_reboot_if_required: true
packages:
  - screen
  - git
  - vim
runcmd:
  - echo "Hello, Pulumi!" > /root/hello-pulumi.txt
"""
)
```

In the provided example, the user data is a cloud-init configuration that:
- Automatically upgrades all system packages (`package_upgrade: true`)
- Reboots the server if the package upgrade requires it (`package_reboot_if_required: true`)
- Installs additional software packages - 'screen', 'git' and 'vim' (under `packages`)
- Executes a shell command upon start-up that creates a new file (`/root/hello-pulumi.txt`) containing the text "Hello, Pulumi!" (under `runcmd`)

You can find more details about the hcloudServer in the ['hcloudServer' resource documentation](https://www.pulumi.com/registry/packages/hcloud/api-docs/hcloud/server/).