Feature flags

Feature flags are used as a way to easily toggle configuration at build time. They are provided to accommodate feature deprecation and downstream configuration changes.

Currently used upstream values for feature flags are set in cloudinit/features.py. Overrides to these values should be patched directly (e.g., via quilt patch) by downstreams.

Each flag should include a short comment regarding the reason for the flag and intended lifetime.

Tests are required for new feature flags, and tests must verify all valid states of a flag, not just the default state.

cloudinit.features.ALLOW_EC2_MIRRORS_ON_NON_AWS_INSTANCE_TYPES = False

When configuring apt mirrors, if ALLOW_EC2_MIRRORS_ON_NON_AWS_INSTANCE_TYPES is True cloud-init will detect that a datasource’s availability_zone property looks like an EC2 availability zone and set the ec2_region variable when generating mirror URLs; this can lead to incorrect mirrors being configured in clouds whose AZs follow EC2’s naming pattern.

As of 20.3, ALLOW_EC2_MIRRORS_ON_NON_AWS_INSTANCE_TYPES is False so we no longer include ec2_region in mirror determination on non-AWS cloud platforms.

If the old behavior is desired, users can provide the appropriate mirrors via apt: directives in cloud-config.

cloudinit.features.APT_DEB822_SOURCE_LIST_FILE = True

On Debian and Ubuntu systems, cc_apt_configure will write a deb822 compatible /etc/apt/sources.list.d/(debian|ubuntu).sources file. When set False, continue to write /etc/apt/sources.list directly.

cloudinit.features.DEPRECATION_INFO_BOUNDARY = 'devel'

DEPRECATION_INFO_BOUNDARY is used by distros to configure at which upstream version to start logging deprecations at a level higher than INFO.

The default value “devel” tells cloud-init to log all deprecations higher than INFO. This value may be overriden by downstreams in order to maintain stable behavior across releases.

Jsonschema key deprecations and inline logger deprecations include a deprecated_version key. When the variable below is set to a version, cloud-init will use that version as a demarcation point. Deprecations which are added after this version will be logged as at an INFO level. Deprecations which predate this version will be logged at the higher DEPRECATED level. Downstreams that want stable log behavior may set the variable below to the first version released in their stable distro. By doing this, they can expect that newly added deprecations will be logged at INFO level. The implication of the different log levels is that logs at DEPRECATED level result in a return code of 2 from cloud-init status.

This may may also be used in some limited cases where new error messages may be logged which increase the risk of regression in stable downstreams where the error was previously unreported yet downstream users expected stable behavior across new cloud-init releases.

format:

<value> :: = <default> | <version> <default> ::= “devel” <version> ::= <major> “.” <minor> [“.” <patch>]

where <major>, <minor>, and <patch> are positive integers

cloudinit.features.ERROR_ON_USER_DATA_FAILURE = True

If there is a failure in obtaining user data (i.e., #include or decompress fails) and ERROR_ON_USER_DATA_FAILURE is False, cloud-init will log a warning and proceed. If it is True, cloud-init will instead raise an exception.

As of 20.3, ERROR_ON_USER_DATA_FAILURE is True.

(This flag can be removed after Focal is no longer supported.)

cloudinit.features.EXPIRE_APPLIES_TO_HASHED_USERS = True

If EXPIRE_APPLIES_TO_HASHED_USERS is True, then when expire is set true in cc_set_passwords, hashed passwords will be expired. Previous to 22.3, only non-hashed passwords were expired.

(This flag can be removed after Jammy is no longer supported.)

cloudinit.features.NETPLAN_CONFIG_ROOT_READ_ONLY = True

If NETPLAN_CONFIG_ROOT_READ_ONLY is True, then netplan configuration will be written as a single root read-only file /etc/netplan/50-cloud-init.yaml. This prevents wifi passwords in network v2 configuration from being world-readable. Prior to 23.1, netplan configuration is world-readable.

(This flag can be removed after Jammy is no longer supported.)

cloudinit.features.NOCLOUD_SEED_URL_APPEND_FORWARD_SLASH = True

Append a forward slash ‘/’ if NoCloud seedurl does not end with either a querystring or forward slash. Prior to 23.1, nocloud seedurl would be used unaltered, appending meta-data, user-data and vendor-data to without URL path separators.

(This flag can be removed when Jammy is no longer supported.)

cloudinit.features.get_features() → Dict[str, bool]

Return a dict of applicable features/overrides and their values.