Capabilities

  • Setting a default locale
  • Setting an instance hostname
  • Generating instance SSH private keys
  • Adding SSH keys to a user’s .ssh/authorized_keys so they can log in
  • Setting up ephemeral mount points
  • Configuring network devices

User configurability

Cloud-init ‘s behavior can be configured via user-data.

User-data can be given by the user at instance launch time.

This is done via the --user-data or --user-data-file argument to ec2-run-instances for example.

  • Check your local clients documentation for how to provide a user-data string or user-data file for usage by cloud-init on instance creation.

Feature detection

Newer versions of cloud-init may have a list of additional features that they support. This allows other applications to detect what features the installed cloud-init supports without having to parse its version number. If present, this list of features will be located at cloudinit.version.FEATURES.

When checking if cloud-init supports a feature, in order to not break the detection script on older versions of cloud-init without the features list, a script similar to the following should be used. Note that this will exit 0 if the feature is supported and 1 otherwise:

import sys
from cloudinit import version
sys.exit('<FEATURE_NAME>' not in getattr(version, 'FEATURES', []))

Currently defined feature names include:

  • NETWORK_CONFIG_V1 support for v1 networking configuration, see curtin documentation for examples.