Why does installing from an existing configuration fail?

Question

I am struggling to install a drupal site from an existing configuration. Here the two approaches I tried:

OPTION 1: Import the config by changing the UID:

• drush cex on existing site
• drush site:install to install new site
• drush cset system.site uuid 478e7e74-fea3...... to set UUID on new site equal to exisiting site
• drush cim on new site

RESULT:

  The import failed due to the following reasons:

  Unexpected error during import with operation delete for taxonomy.vocabulary.tags: Attempt to create a field body that does not exist on entity type node.
  Unexpected error during import with operation delete for shortcut.set.default: Attempt to create a field body that does not exist on entity type node.
  Unexpected error during import with operation delete for contact.form.personal: Attempt to create a field body that does not exist on entity type node.

.... (There are many more of these errors, but I stripped them here for better readability)

OPTION 2: Provide existing config during installation already

drush site:install --existing-config with config from existing site being avilable in config directory of new site.

RESULT:

The selected profile has a hook_install() implementation and therefore can
not be installed from configuration.

Answer 1

I think option 1 is more of a hacky workaround than a recommended approach. I would avoid it in favor of option 2.

Re: option 2 failing, the error message is pretty clear - you can't use the --existing-config option with a profile that implements an install hook.

From the change record introducing the ability to install from existing configuration:

If the profile implements hook_install() configuration install is not supported. This might be addressed in #2982052: Allow an install hook in profiles installing from configuration. Possible workarounds for now are to either change the install profile to minimal or follow option 2 and create a new profile that does not implement the hook.

Drupal 8: Install Site From Existing Configuration walks through how to change your installation to use the minimal profile instead of your current profile. Spoiler: you just need to make two updates to the core.extension.yml file in your config directory:

1. Change the profile key's value to minimal
2. Under the modules key, replace your existing profile's key with minimal. (Profiles will typically be near the bottom of the list.)