Learn what cloud-init is and how to use it.
What do you need to complete this tutorial?
To test your cloud-init script, you can use any of the big cloud providers (Azure, AWS, Hetzner…).
What is cloud-init?
Cloud-init is a tool to prepare your cloud Linux VMs before using. For example, you could install necessary software to create a CI/CD pipeline like Docker, Nomad by installing the corresponding packages or harden your VM by configuring intrusion detection software, disabling root login and setting a non-standard SSH port. You can also read metadata about the cloud environment and configure your VM based on that.
It is available on all major Linux distributions and cloud platforms.
A simple cloud-init script
Here is a very simple and self-explanatory cloud-configuration which creates a user and installs some packages. You can test it by creating a VM on the cloud platform of your choice which should give you an option to provide it for initialization.
Log in to the new VM with the configured user and password and browse the cloud-init logs, which can be found under