Cloud-Init Generator

Cigen is a small bash script that will populate a templated Cloud-Init user-data file using envsubst. It is integrated with Scrap-Metal as the primary tool for boot-strapping user-data files for cloud-image based virtual-machines.

A small selection of templates for use with Cigen + Scrap-Metal are maintained here: cigen-community-templates.

Options

Available options:

-h, --help              Print this help and exit

-v, --verbose           Print script debug info

-upd, --update          Update apt packages during provisioning
                        Defaults to False

-upg, --upg             Upgrade packages during provisioning
                        Defaults to False

-t, --template          The template to use as the base for clopud-init.
                        Templates are located in the templates directory.
                        Defaults to 'slim.yaml' if no value specified.

-p, --password          Password to set up for the VM Users. 
                        Defaults to 'password' if no value is specified

-u, --username          Username for non-system account
                        Defaults to the current shell user

-gh, --github-username  (Optional) Github username from which to pull public keys

-n, --vm-name           Hostname/name for the Virtual Machine. Influences the 
                        name of the syste account - no special chars plz.

-e, --extra-vars        Some templates will require extra values.
                        Use this option to supply these values as 
                        Key-Value-Pairs separated via commas.
                        Example: -e "VAR0='some string'","VAR1=$(pwd)"

Basic Usage

# Downloading a template from the community repo
wget -O slim.yaml https://raw.githubusercontent.com/cloudymax/cigen-community-templates/main/slim.yaml

PASSWD="SomeP@ssw0rd!"
GITHUB_USER="some-gh-user"
USER="some-user"
VM_NAME="testmv"

docker build -t cigen . && \
docker run -it -v $(pwd)/slim.yaml:/cloud-init-template.yaml \
    -v $(pwd):/output cigen \
    ./cigen.sh --update --upgrade \
    --password "${PASSWD}" \
    --github-username "${GITHUB_USER}" \
    --username "${USER}" \
    --vm-name "${VM_NAME}" \
    --template "/cloud-init-template.yaml"

Advanced Usage with Extra Vars

Some templates will require additional variabels aside from those specified in the --help. To supply extra variables used the -e or --extra-vars flag and provide the extra values as a comma-separated list of Key-Value-Pairs represented as strings without linebreaks or spaces between them.

Example:

docker run -it -v "/path/to/template.yaml":/cloud-init-template.yaml \
    -v $(pwd):/output cigen \
    ./cigen.sh --update --upgrade \
    --password "${PASSWD}" \
    --github-username "${GITHUB_USER}" \
    --username "${USER}" \
    --vm-name "${VM_NAME}" \
    --extra-vars "INTERFACE=enp4s0","IP_ADDRESS=192.168.50.100","GATEWAY_IP=192.168.50.1","DNS_SERVER_IP=192.168.50.50","ROOT_USER=max"

Why Cloud-Init?

Cloud-Init officially supports 8 OSs - Ubuntu, Arch Linux, CentOS, Red Hat, FreeBSD, Fedora, Gentoo Linux, and openSUSE. These examples have been developed and tested for use with Ubuntu.

Use on bare-metal:

• PXEless

On self-hosted VMs:

• Scrap-Metal
• Multipass

Or via Terraform on most major clouds:

• Equinix Metal
• AWS EC2
• Azure Compute
• Digital Ocean Droplets
• Google Compute Engine (as metadata field)
• Terraform templating module for cloud-init

Cloud-Init Docs:

• Cloud-Init Official Docs
• Extra examples from Canonical

Debugging

Docs link: https://cloudinit.readthedocs.io/en/latest/topics/debugging.html

cloud-init logs are located in:

• /run/cloud-init/result.json
• /var/log/cloud-init.log
• /var/log/cloud-init-output.log

If you want to debug the user-data in cloud-init, try the following steps:

• Reset and re-run

  sudo rm -rf /var/lib/cloud/*
  sudo cloud-init init
  sudo cloud-init modules -m final

• Analyze logs

  sudo cloud-init analyze show -i /var/log/cloud-init.log
  sudo cloud-init analyze dump -i /var/log/cloud-init.log
  sudo cloud-init analyze blame -i /var/log/cloud-init.log

• Run single module sudo cloud-init single --name cc_ssh --frequency always