kitchen diagnose

Prints the fully computed configuration for one or more instances as YAML — every default applied, every ERB expression evaluated, every layer of configuration merged. When kitchen.yml does not behave the way you expect, this is the command that shows you why.

kitchen diagnose [INSTANCE|REGEXP|all]

Examples

kitchen diagnose                          # instance config for every instance
kitchen diagnose default-ubuntu-2204      # one instance
kitchen diagnose --all                    # everything, including loader and plugins
kitchen diagnose --loader                 # how the config files were merged
kitchen diagnose --plugins                # which plugin versions are loaded
kitchen diagnose --no-instances --plugins # plugins only, no instance dump

Flags

Debugging configuration precedence

Test Kitchen merges up to three YAML files, and configuration can be set at the top level, per suite, and per platform. Working out what actually won by reading the files is error-prone. --loader shows the merge itself:

kitchen diagnose --loader --no-instances

The output reports each config file, whether it was found, and the raw data it contributed:

loader:
  global_config:
    filename: "/home/user/.kitchen/config.yml"
    raw_data:
      ...
  project_config:
    filename: "/path/to/project/kitchen.yml"
    raw_data:
      ...
  local_config:
    filename: "/path/to/project/kitchen.local.yml"
    raw_data:
      ...

If a setting you expected is missing, compare raw_data against the merged instance output to see which layer overrode it.

Checking plugin versions

kitchen diagnose --plugins --no-instances

This reports the driver, provisioner, transport, and verifier plugins Test Kitchen resolved, along with their versions. It answers “which kitchen-ec2 am I actually running?” — which matters when several Ruby environments are installed and a gem install landed somewhere unexpected.

Verifying ERB and dynamic configuration

kitchen.yml supports ERB, so a config file can contain logic:

driver:
  name: ec2
  region: <%= ENV['AWS_REGION'] || 'us-west-2' %>

kitchen diagnose shows the result after evaluation, so you can confirm what the expression produced instead of guessing:

kitchen diagnose default-ubuntu-2204 | grep region

kitchen diagnose --all > before.yml
# edit kitchen.yml
kitchen diagnose --all > after.yml
diff before.yml after.yml

Reporting bugs

When filing an issue against Test Kitchen or a plugin, kitchen diagnose --all output is the single most useful thing you can include. It captures your configuration, plugin versions, and Ruby environment in one place.