Cloud-Init - Compute Desk

Overview

Pass a cloud_init script when procuring an offer to configure the instance automatically on first boot. Two formats are supported:

Cloud-config YAML

Use #cloud-config for declarative configuration — package installation, file creation, and commands:

{
  "offer_id": "abc-123",
  "ssh_public_key": "ssh-ed25519 AAAA...",
  "cloud_init": "#cloud-config\npackages:\n  - htop\n  - jq\n  - python3-pip\nwrite_files:\n  - path: /opt/config.yml\n    content: |\n      model: llama-3\n      batch_size: 32\nruncmd:\n  - pip3 install numpy torch\n  - echo 'Setup complete' > /tmp/ready.txt"
}

Supported directives:

packages — apt packages to install
write_files — files to create (with optional permissions)
runcmd — shell commands to run after boot

Shell script

Use #!/bin/bash for full shell scripting control:

{
  "offer_id": "abc-123",
  "ssh_public_key": "ssh-ed25519 AAAA...",
  "cloud_init": "#!/bin/bash\nset -e\napt-get update && apt-get install -y htop jq\npip3 install torch\necho 'Setup complete' > /tmp/ready.txt"
}

How it works

The cloud-init script is injected into the instance’s startup script. Some vendors support native cloud-init (Lambda Labs, Nebius), while others convert the script to bash commands automatically. The conversion is transparent — you always pass the same #cloud-config YAML or #!/bin/bash script regardless of vendor.

Scripts run as root and with set -e — any command failure will stop execution of remaining commands. For pip installs that may fail on older systems, use fallback patterns:

pip3 install --break-system-packages numpy 2>/dev/null || pip3 install numpy

Verifying cloud-init ran

SSH into the instance and check your expected outputs:

# Check if packages are installed
which htop jq

# Check if files were created
cat /opt/config.yml

# Check runcmd output
cat /tmp/ready.txt

Limitations

Cloud-init runs once on first boot only
Maximum script size varies by vendor (generally 16KB-64KB)
#cloud-config packages directive requires apt (Ubuntu/Debian images)
Some vendors may have delays between instance readiness and cloud-init completion

​Overview

​Cloud-config YAML

​Shell script

​How it works

​Verifying cloud-init ran