Migrating a website script version is one of the most complicated task a webmaster has to deal with when managing a website. Migrating to Drupal 8? Here is a small guide with various details. Let’s start with general info : How to log into your site in maintenance mode. If you put your site into maintenance mode (using the configuration page of the admin section of your site), it will not be accessible to internet users who are not logged into the site. This is handy to keep it hidden while you’re still developing it. If you go ahead and log out of the site, however, it will not be accessible to you either. Ooops! The solution is to go to www.nameofyoursite.com/user/login. Then you can log back in.
Note: Earlier, there used to be a migrate_plus module in Drupal 8 core which contained all the pieces of migrate functionality that wasn’t able to make it in the Drupal 7 core. It contained all the plugins for the support of XML, CSV and JSON data sources along with the support for databases like MS SQL or Oracle. This module has now been split into different modules, namely migrate_plus, migrate_tools and migrate_source_csv. After proceeding, you will be brought to the Migrate UI where you can check all the potential issues and errors that you might encounter as well as all the available and the missing paths. Go through this screen and when satisfied, start the migration.
The upgrade process, and underlying Migration API, are still evolving. We don’t anticipate them changing dramatically even though they are still marked experimental. Beware of any resources that were written before Drupal 8.1.x was released (April 19, 2016) as the system changed considerably in ways that invalidate many of the older articles.
Download the latest release of the distribution. Download and extract the latest release and copy your existing site’s Drupal 7 version settings.php file and files directory to the sites/default directory in the distribution install. This will point the new site to your existing site database.
The steps above outline how to get a distribution minimally installed on an existing site. But you’ll still have a lot of work to do to reconcile your existing site content and structure with what has been created by the distribution. Here are a few tips to get you started–but you should begin with the assumption that there will be lots more you’ll discover and need to fix. Most distributions are built using the Features module, which allows exporting configuration from a Drupal site – content types, fields, views, and so on – into code, so that it can be enabled on multiple sites. For components like content types and fields to be exportable, they need to have a “machine name”–a unique name that will be the same on every site they’re enabled on. For example, a date-type field used to store the date of an event might have the machine name field_date. Read extra info on Upgrading from Drupal 7 to Drupal 8.