How to find files#

Cloud-init log files#

Cloud-init uses two files to log to:

  • /var/log/cloud-init-output.log: Captures the output from each stage of cloud-init when it runs.

  • /var/log/cloud-init.log: Very detailed log with debugging output, describing each action taken.

  • /run/cloud-init: Contains logs about how cloud-init enabled or disabled itself, as well as what platforms/datasources were detected. These logs are most useful when trying to determine what cloud-init did or did not run.

Be aware that each time a system boots, new logs are appended to the files in /var/log. Therefore, the files may contain information from more than one boot.

When reviewing these logs, look for errors or Python tracebacks.

Configuration files#

Cloud-init configuration files are provided in two places:

  • /etc/cloud/cloud.cfg

  • /etc/cloud/cloud.cfg.d/*.cfg

These files can define the modules that run during instance initialisation, the datasources to evaluate on boot, as well as other settings.

See the configuration sources explanation and configuration reference pages for more details.

Data files#

Inside the /var/lib/cloud/ directory there are two important subdirectories:


The /var/lib/cloud/instance directory is a symbolic link that points to the most recently used instance-id directory. This folder contains the information cloud-init received from datasources, including vendor and user data. This can help to determine that the correct data was passed.

It also contains the datasource file that contains the full information about which datasource was identified and used to set up the system.

Finally, the boot-finished file is the last thing that cloud-init creates.


The /var/lib/cloud/data directory contain information related to the previous boot:

  • instance-id: ID of the instance as discovered by cloud-init. Changing this file has no effect.

  • result.json: JSON file showing both the datasource used to set up the instance, and whether any errors occurred.

  • status.json: JSON file showing the datasource used, a breakdown of all four modules, whether any errors occurred, and the start and stop times.