Support for Drupal 7 is ending on 5 January 2025—it’s time to migrate to Drupal 10! Learn about the many benefits of Drupal 10 and find migration tools in our resource center.I am working on resolving some issues in a Drupal 7 to 8 migration. The Drupal 8 site was handed to me after the site migration had been run and much of the site configuration (e.g. views, blocks, etc.) added. None of the site configuration is in code. In order to troubleshoot/resolve the migration issues without losing the rest of the site configuration already in place, I was thinking of rolling back the migration and then re-migrating.
One thing I have noticed in most tutorials about Drupal 7 to 8 migration, is that they say you need to start with an empty site (The upgrade migration process generates the relevant Drupal 8 structures/configuration during the migration/upgrade process). Given that my site already has migrated content, all of the content types, etc. normally generated by the migration/upgrade process is already in place. Is it possible to run a standard Drupal 7 to Drupal 8 migration on a site with these existing content structures (e.g. content types, etc.) already in place or is it essential to start with an empty site as directed by most tutorials on the topic?
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Comment #2
cilefen CreditAttribution: cilefen commentedComment #3
quietone CreditAttribution: quietone as a volunteer commentedadd tag.
Comment #4
BenStallings CreditAttribution: BenStallings commentedHi, Begun. I hope you haven't been waiting all this time for an answer! I just gave a presentation at a camp yesterday that may be applicable: https://tinyurl.com/drupalcorn-migrating and I'm now at a contrib day trying to help improve the documentation on this topic, which as you've seen is badly lacking.
In brief, you can use the functionality of drupal_migrate module without using its /upgrade feature that blows away your whole site. Each of the core modules comes with a migrations directory containing YML files that you can use as templates, and also a src/plugins/migrate directory containing plugin classes that you can extend or substitute with your own classes. You will have to write some code to make this happen, at the very least YML, but it's pretty straightforward compared to how we did it in Drupal 7.
For example... if you wanted to import just Blog nodes from your D7 site, you would copy the core/modules/node/migrations/d7_node.yml file to your ../config/sync/migrate_plus.migration.blog.yml and edit it to set
id: blog, and just under the sourceplugin: d7_nodespecifynode_type: blog. Under process, follow the instructions to remove the nid and vid fields. Then add in the fields you do want to import. Finally, remove the dependencies so thatrequired: { }andoptional: { }. Then import the configuration and try importing blogs!Good luck!
Comment #5
BenStallings CreditAttribution: BenStallings as a volunteer commentedsetting to Needs Review
Comment #6
maxocub CreditAttribution: maxocub commentedLet's leave this on Active as there is no patch to review.
Comment #7
quietone CreditAttribution: quietone as a volunteer commented@Begun, has this been resolved?
If one upgrades from the UI at /upgrade the source IDs, for example nids, are not changed on the destination site. So, any new content on the destination that has the same nid as a node on the source will be over-written and the newly added content will be lost.
To migrate to a Drupal 8/Drupal 9 site that has existing content then some migration yml need to be modified. For example, take a look at th d6_node.yml file.
Comment #10
quietone CreditAttribution: quietone as a volunteer commentedIs this issue still a problem?
There has been no activity here for 7 months.
Since we need more information to move forward with this issue, I am keeping the status at Postponed (maintainer needs more info). If we don't receive additional information to help with the issue, it may be closed after three months.
Comment #11
benjifisher