Pre-configure your dev environment with Gcore VM init scripts

Provisioning new cloud instances can be repetitive and time-consuming if you’re doing everything manually: installing packages, configuring environments, copying SSH keys, and more. With cloud-init, you can automate these tasks and launch development-ready instances from the start.

Gcore Edge Cloud VMs support cloud-init out of the box. With a simple YAML script, you can automatically set up a development-ready instance at boot, whether you’re launching a single machine or spinning up a fleet.

In this guide, we’ll walk through how to use cloud-init on Gcore Edge Cloud to:

• Set a password
• Install packages and system updates
• Add users and SSH keys
• Mount disks and write files
• Register services or install tooling like Docker or Node.js

Let’s get started.

What is cloud-init?

cloud-init is a widely used tool for customizing cloud instances during the first boot. It reads user-provided configuration data—usually YAML—and uses it to run commands, install packages, and configure the system. In this article, we will focus on Linux-based virtual machines.

How to use cloud-init on Gcore

For Gcore Cloud VMs, cloud-init scripts are added during instance creation using the User data field in the UI or API.

Step 1: Create a basic script

Start with a simple YAML script. Here’s one that updates packages and installs htop:

#cloud-config
package_update: true
packages:
  - htop

Step 2: Launch a new VM with your script

Go to the Gcore Customer Portal, navigate to VMs, and start creating a new instance (or just click here). When you reach the Additional options section, enable the User data option. Then, paste in your YAML cloud-init script.

Once the VM boots, it will automatically run the script. This works the same way for all supported Linux distributions available through Gcore.

3 real-world examples

Let’s look at three examples of how you can use this.

Example 1: Add a password for a specific user

The below script sets the for the default user of the selected operating system:

#cloud-config
password: <password>
chpasswd: {expire: False}
ssh_pwauth: True

Example 2: Dev environment with Docker and Git

The following script does the following:

• Installs Docker and Git
• Adds a new user devuser with sudo privileges
• Authorizes an SSH key
• Starts Docker at boot

#cloud-config
package_update: true
packages:
  - docker.io
  - git
users:
  - default
  - name: devuser
    sudo: ALL=(ALL) NOPASSWD:ALL
    groups: docker
    shell: /bin/bash
    ssh-authorized-keys:
  - ssh-rsa AAAAB3Nza...your-key-here
runcmd:
  - systemctl enable docker
  - systemctl start docker

Example 3: Install Node.js and clone a repo

This script installs Node.js and clones a GitHub repo to your Gcore VM at launch:

#cloud-config
packages:
  - curl
runcmd:
  - curl -fsSL https://deb.nodesource.com/setup_18.x | bash -
  - apt-get install -y nodejs
  - git clone https://github.com/example-user/dev-project.git


/home/devuser/project

Reusing and versioning your scripts

To avoid reinventing the wheel, keep your cloud-init scripts:

• In version control (e.g., Git)
• Templated for different environments (e.g., dev vs staging)
• Modular so you can reuse base blocks across projects

You can also use tools like Ansible or Terraform with cloud-init blocks to standardize provisioning across your team or multiple Gcore VM environments.

Debugging cloud-init

If your script doesn’t behave as expected, SSH into the instance and check the cloud-init logs:

sudo cat /var/log/cloud-init-output.log

This file shows each command as it ran and any errors that occurred.

Other helpful logs:

/var/log/cloud-init.log
/var/lib/cloud/instance/user-data.txt

Pro tip: Echo commands or write log files in your script to help debug tricky setups—especially useful if you’re automating multi-node workflows across Gcore Cloud.

Tips and best practices

• Indentation matters! YAML is picky. Use spaces, not tabs.
• Always start the file with #cloud-config.
• runcmd is for commands that run at the end of boot.
• Use write_files to write configs, env variables, or secrets.
• Cloud-init scripts only run on the first boot. To re-run, you’ll need to manually trigger cloud-init or re-create the VM.

Automate it all with Gcore

If you're provisioning manually, you're doing it wrong. Cloud-init lets you treat your VM setup as code: portable, repeatable, and testable. Whether you’re spinning up ephemeral dev boxes or preparing staging environments, Gcore’s support for cloud-init means you can automate it all.

For more on managing virtual machines with Gcore, check out our product documentation.

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