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
.
Currently defined feature names include:
NETWORK_CONFIG_V1
support for v1 networking configuration, see Networking Config Version 1 documentation for examples.NETWORK_CONFIG_V2
support for v2 networking configuration, see Networking Config Version 2 documentation for examples.
CLI Interface¶
The command line documentation is accessible on any cloud-init installed system:
% cloud-init --help
usage: cloud-init [-h] [--version] [--file FILES]
[--debug] [--force]
{init,modules,single,dhclient-hook,features,analyze,devel,collect-logs,clean,status}
...
optional arguments:
-h, --help show this help message and exit
--version, -v show program's version number and exit
--file FILES, -f FILES
additional yaml configuration files to use
--debug, -d show additional pre-action logging (default: False)
--force force running even if no datasource is found (use at
your own risk)
Subcommands:
{init,modules,single,dhclient-hook,features,analyze,devel,collect-logs,clean,status}
init initializes cloud-init and performs initial modules
modules activates modules using a given configuration key
single run a single module
dhclient-hook run the dhclient hookto record network info
features list defined features
analyze Devel tool: Analyze cloud-init logs and data
devel Run development tools
collect-logs Collect and tar all cloud-init debug info
clean Remove logs and artifacts so cloud-init can re-run.
status Report cloud-init status or wait on completion.
CLI Subcommand details¶
cloud-init features¶
Print out each feature supported. If cloud-init does not have the features subcommand, it also does not support any features described in this document.
% cloud-init features
NETWORK_CONFIG_V1
NETWORK_CONFIG_V2
cloud-init status¶
Report whether cloud-init is running, done, disabled or errored. Exits non-zero if an error is detected in cloud-init.
- –long: Detailed status information.
- –wait: Block until cloud-init completes.
% cloud-init status --long
status: done
time: Wed, 17 Jan 2018 20:41:59 +0000
detail:
DataSourceNoCloud [seed=/var/lib/cloud/seed/nocloud-net][dsmode=net]
# Cloud-init running still short versus long options
% cloud-init status
status: running
% cloud-init status --long
status: running
time: Fri, 26 Jan 2018 21:39:43 +0000
detail:
Running in stage: init-local
cloud-init collect-logs¶
Collect and tar cloud-init generated logs, data files and system information for triage. This subcommand is integrated with apport.
Note: Ubuntu users can file bugs with ubuntu-bug cloud-init to automaticaly attach these logs to a bug report.
Logs collected are:
- /var/log/cloud-init*log
- /run/cloud-init
- cloud-init package version
- dmesg output
- journalctl output
- /var/lib/cloud/instance/user-data.txt
cloud-init analyze¶
Get detailed reports of where cloud-init spends most of its time. See Boot Time Analysis - cloud-init analyze for more info.
- blame Report ordered by most costly operations.
- dump Machine-readable JSON dump of all cloud-init tracked events.
- show show time-ordered report of the cost of operations during each boot stage.
cloud-init devel¶
Collection of development tools under active development. These tools will likely be promoted to top-level subcommands when stable.
cloud-init devel schema
: A #cloud-config format and schema validator. It accepts a cloud-config yaml file and annotates potential schema errors locally without the need for deployment. Schema validation is work in progress and supports a subset of cloud-config modules.
cloud-init clean¶
Remove cloud-init artifacts from /var/lib/cloud and optionally reboot the machine to so cloud-init re-runs all stages as it did on first boot.
- –logs: Optionally remove /var/log/cloud-init*log files.
- –reboot: Reboot the system after removing artifacts.
cloud-init init¶
Generally run by OS init systems to execute cloud-init’s stages init and init-local. See Boot Stages for more info. Can be run on the commandline, but is generally gated to run only once due to semaphores in /var/lib/cloud/instance/sem/ and /var/lib/cloud/sem.
- –local: Run init-local stage instead of init.
cloud-init modules¶
Generally run by OS init systems to execute modules:config and
modules:final boot stages. This executes cloud config Modules
configured to run in the init, config and final stages. The modules are
declared to run in various boot stages in the file
/etc/cloud/cloud.cfg under keys cloud_init_modules,
cloud_init_modules and cloud_init_modules. Can be run on the
commandline, but each module is gated to run only once due to semaphores
in /var/lib/cloud/
.
- –mode (init|config|final): Run modules:init, modules:config or modules:final cloud-init stages. See Boot Stages for more info.
cloud-init single¶
Attempt to run a single named cloud config module. The following example re-runs the cc_set_hostname module ignoring the module default frequency of once-per-instance:
- –name: The cloud-config module name to run
- –frequency: Optionally override the declared module frequency with one of (always|once-per-instance|once)
% cloud-init single --name set_hostname --frequency always
Note: Mileage may vary trying to re-run each cloud-config module, as some are not idempotent.