Migration Part I : Drupal to Drupal migration

Drupal 8 core provides support for Drupal-to-Drupal migrations. it will allow you to migrate your content from previous versions to Drupal 8.

Core:

• Migrate
• Migrate Drupal

Contributed:

• Migrate Upgrade (drupal.org/project/migrate_upgrade)
• Migrate Tools (drupal.org/project/migrate_tools)
• Migrate Plus (drupal.org/project/migrate_plus)

Step 1 - goto your drupal 8 site setting.php and add the drupal 7 db setting in this file,

so default drupal 8 db settings comes with 

$database['default']['default']  copy this and make new key named as 

$database['upgrade']['default'] like below

$databases['upgrade']['default'] = array (
  'database' => 'dbname',
  'username' => 'dbuser',
  'password' => 'dbpass',
  'prefix' => '',
  'host' => 'localhost',
  'port' => '3306',
  'namespace' => 'Drupal\\Core\\Database\\Driver\\mysql',
  'driver' => 'mysql',
);

Make sure to have enable config properly the config folder in
$config_directories['staging'] // for drupal 7 config files
$config_directories['sync'] // for drupal 8 config files
Step-2  : Run the migration command from drupal 8  root

drush migrate-upgrade --configure-only

This command will generate migration configuration entities in the drupal 8 site, All the drupal 7 configuration would be availbale to the drupal 8 , next we will export these configuration in a directory in d8
Let suppose we are exporting these drupal 7 config in drupal8_root/tmp/migrate folder

drush config-export --destination=/tmp/migrate

Now You have two config in drupal 8 site, one is /tmp/migrate it has all the drupal 7 config and another is drupal8 /sites/default/config drupal 8 config files,,,,




So if we start migration then we have to copy the config files from /tmp/migrate   -> /sites/default/config folder.....

Lets Suppose we want to migrate only users then we would copy only two files as below,and paste it into the /sites/default/config

migrate_plus.migration_group.migrate_drupal7.yml

migrate_plus.migration_upgrade_d7_user.yml

We have to define one more db settting in d8 site with the key of drupal_7

it is defined in the (migrate_plus.migration_group.migrate_drupal7.yml) file

$databases['drupal_7']['default'] = array (
  'database' => 'dbname',
  'username' => 'dbuser',
  'password' => 'dbpass',
  'prefix' => '',
  'host' => 'localhost',
  'port' => '3306',
  'namespace' => 'Drupal\\Core\\Database\\Driver\\mysql',
  'driver' => 'mysql',
);

Now run
Drush config-import staging

Drush ms (will show you the status of migration)

Drush mi upgrade_d7_user

All Done.  That is the process of drupal to drupal migration

A Guide for Upgrading a Drupal 7 Website to Drupal 8

Drupal 8 core comes bundled with the following migration modules:

• Migrate: This is the core upgrade API module.
• Migrate Drupal: This module consists of all the classes that are required for migration/upgrade from Drupal 7 to Drupal 8.
• Migrate Upgrade: This is the module that provides the user with a simple and easy to use UI for performing the migration from Drupal 7 to Drupal 8.

• Upgrade Drupal

  Make sure that you have checked off all the items on the pre-upgrade checklist. It is time to start the actual migration process. The following steps make up the upgrade process.
1. Make a local copy of your original website
2. Download the latest Drupal 8 version
3. Make a local Drupal 8 website
4. Verify that you have the migrate upgrade module
5. Enable the required modules
6. Navigate to the Upgrade Path
7. Enter the details
8. Start the migration
• ref https://www.cloudways.com/blog/upgrade-drupal-7-to-drupal-8/

Ref: https://www.youtube.com/watch?v=_z2FH0efd_g
https://drupalize.me/blog/201604/custom-drupal-drupal-migrations-migrate-tools