Enabling Solr on Drupal 8

Detailed information on using Apache Solr with Drupal 8.

Contributors: Peter Sawczynec

Apache Solr is a system for indexing and searching site content.

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Before You Begin

Be sure that you:

  • Enable Solr in the Pantheon Site Dashboard: Settings > Add Ons > Apache Solr Index Server: Add.
  • Install Composer
  • Create a Composer managed site on Pantheon following the Build Tools guide


Solr on Drupal 8 requires a Composer managed workflow, as described in our Build Tools guide. Since one module relies on Solarium, an external library, in addition to Composer's autoloader, we cannot support non-Composer workflows for Solr on Drupal 8. For details, see this Drupal.org issue.

Install Solr on Drupal 8

Install the Search API Pantheon Module

  1. Navigate to the project's root directory on your local computer, then checkout a new branch from master:

    git checkout -b solr master
  2. Add the Search API Pantheon module as a required dependency:

    composer require "drupal/search_api_pantheon ~1.0" --prefer-dist
  3. You should now have the Search API Pantheon module installed along with it's dependencies. Run git status to make sure you see the expected result (only two files modified). Commit the changes to composer.json and composer.lock and push to GitHub:

    git commit -am "Require drupal/search_api_pantheon ~1.0"
    git push origin solr

    Require search API output

  4. Return to GitHub and compare your feature branch against master. The remaining sections should be completed on the Multidev environment created as part of the PR's build process. Once configured, export the code and deploy as described in Build Tools.

Configure Solr

To configure the connection with Pantheon, set the connection mode to SFTP and complete the following on the Multidev environment:

Enable Modules

Enable the Search API Pantheon module via the Drupal interface. When prompted, click Continue to enable the Search API and Search API Solr modules:

Disable Drupal Core's Search Module (Optional)

If you are using Search API, then you probably will not be using Drupal Core's Search module. Uninstall the Search core module from /admin/modules/uninstall to avoid confusion in further configuration steps.

Add The Search Server

Navigate to /admin/config/search/search-api/add-server and configure the following, then click Save:

  • Server name: Pantheon
  • Backend: Solr
  • Solr Connector: Pantheon
  • Schema file: modules/search_api_solr/solr-conf/4.x/schema.xml (recommended)

You can name the server anything you want but using something like "Pantheon" is a good way to remember where the connection goes. The Search API module provides schema files for each version of Solr (4, 5, and 6). You can customize schema files by copying these examples to your own custom module and editing them. If you are just getting started, we recommend selecting the file for Solr 4.

Add Search Index

Navigate to admin/config/search/search-api/add-index and name your index, then choose a data source. If this is your first time using Search API, start by selecting Content as a data source. This option will index articles, basic pages, and other node types you have configured.

Select Pantheon as the server, then click Save and add fields. Add fields to be included in the index and click Done.

After adding fields the configuration, make sure the index is full by clicking Index now or by running cron.

Export Configuration

It is a best practice in Drupal 8 to export your changes to yml files. You can quickly export configuration changes via Terminus:

terminus drush <site>.solr -- config-export -y

Search the Index

To actually search your index you will need a module like Search API Pages, which allows for the configuration of search forms on their own pages.

Solr Versions and Schemas

Currently, the version of Solr on Pantheon is Apache Solr v3.6. Officially, the lowest supported version of Solr in Search API Solr is Solr 4. Pantheon will soon offer a higher version of Solr. Until then, you can use the schema for Solr 4 that Search API Pantheon provides.

Force Reposting of Schema File on Pantheon Environments

Each Pantheon environment (Dev, Test, Live, and Multidevs) has its own Solr server. So indexing and searching in one environment does not impact any other environment. Currently, the schema file must be reposted to each environment's Solr server. To do so, re-save the search server (e.g. /admin/config/search/search-api/server/pantheon/edit).

Before this module is released as a Beta, reposting the schema file will be done automatically. For details, see https://www.drupal.org/node/2775549.

See Also