diff --git a/.docker/solr.dockerfile b/.docker/solr.dockerfile
index 6bc701b625..c16c36b5e0 100644
--- a/.docker/solr.dockerfile
+++ b/.docker/solr.dockerfile
@@ -18,13 +18,18 @@ COPY .docker/config/solr/config-set /solr-conf/conf/
 USER root
 
 # Apply custom modifications for Lagoon environment compatibility.
+# The index is moved out of the core directory, which is recreated on every
+# start, so the build fails if the dataDir replacement does not apply.
 RUN sed -i -e "s#<dataDir>\${solr.data.dir:}#<dataDir>/var/solr/\${solr.core.name}#g" /solr-conf/conf/solrconfig.xml && \
+    grep -q "<dataDir>/var/solr/\${solr.core.name}</dataDir>" /solr-conf/conf/solrconfig.xml && \
     sed -i -e "s#solr.lock.type:native#solr.lock.type:none#g" /solr-conf/conf/solrconfig.xml && \
     sed -i -e "s#solr.autoSoftCommit.MaxTime=5000#solr.autoSoftCommit.MaxTime=-1#g" /solr-conf/conf/solrcore.properties
 
 # hadolint ignore=DL3066 # named account provided by the base image
 USER solr
 
-# solr-precreate is provided by the base Solr container image.
-# It pre-creates the core and then starts Solr in the foreground.
-CMD ["solr-precreate", "drupal", "/solr-conf"]
+# solr-recreate and solr-foreground are provided by the base Solr container
+# image. solr-recreate replaces the core config on the persistent volume with
+# the config-set from this image on every start, so config-set changes reach
+# existing cores. exec makes Solr the direct child of tini to receive SIGTERM.
+CMD ["sh", "-c", "solr-recreate drupal /solr-conf && exec solr-foreground"]
diff --git a/.vortex/docs/content/development/environment/docker.mdx b/.vortex/docs/content/development/environment/docker.mdx
index d556af4af8..dc8f9d55e5 100644
--- a/.vortex/docs/content/development/environment/docker.mdx
+++ b/.vortex/docs/content/development/environment/docker.mdx
@@ -351,6 +351,16 @@ there only when you enable the matching feature in the installer:
   and keep it under version control. You reach Solr from the host on a
   random port, which `docker compose port solr 8983` prints. The Solr admin
   interface is at `http://localhost:<port>/solr/`.
+
+  The container recreates the `drupal` core from the image's config-set on
+  every start. A config-set change reaches an existing core on the next
+  deployment, even when `/var/solr` is a persistent volume. The index lives
+  in `/var/solr/drupal`, outside the core directory, so it survives each
+  restart. The build fails when the config-set's `dataDir` line differs from
+  `<dataDir>${solr.data.dir:}</dataDir>`, because the index would otherwise
+  sit inside the recreated core. After a config-set change that alters the
+  schema, reindex the content with `ahoy drush search-api:rebuild-tracker`
+  and `ahoy drush search-api:index`.
 - `clamav` - an optional container that runs a ClamAV antivirus server,
   which Drupal uses to scan uploaded files for viruses.
 - `chrome` - runs Chromium, the open source browser that Chrome is built
diff --git a/.vortex/installer/tests/Fixtures/handler_process/_baseline/.docker/solr.dockerfile b/.vortex/installer/tests/Fixtures/handler_process/_baseline/.docker/solr.dockerfile
index 0ebae6b908..afccfc4b9e 100644
--- a/.vortex/installer/tests/Fixtures/handler_process/_baseline/.docker/solr.dockerfile
+++ b/.vortex/installer/tests/Fixtures/handler_process/_baseline/.docker/solr.dockerfile
@@ -18,13 +18,18 @@ COPY .docker/config/solr/config-set /solr-conf/conf/
 USER root
 
 # Apply custom modifications for Lagoon environment compatibility.
+# The index is moved out of the core directory, which is recreated on every
+# start, so the build fails if the dataDir replacement does not apply.
 RUN sed -i -e "s#<dataDir>\${solr.data.dir:}#<dataDir>/var/solr/\${solr.core.name}#g" /solr-conf/conf/solrconfig.xml && \
+    grep -q "<dataDir>/var/solr/\${solr.core.name}</dataDir>" /solr-conf/conf/solrconfig.xml && \
     sed -i -e "s#solr.lock.type:native#solr.lock.type:none#g" /solr-conf/conf/solrconfig.xml && \
     sed -i -e "s#solr.autoSoftCommit.MaxTime=5000#solr.autoSoftCommit.MaxTime=-1#g" /solr-conf/conf/solrcore.properties
 
 # hadolint ignore=DL3066 # named account provided by the base image
 USER solr
 
-# solr-precreate is provided by the base Solr container image.
-# It pre-creates the core and then starts Solr in the foreground.
-CMD ["solr-precreate", "drupal", "/solr-conf"]
+# solr-recreate and solr-foreground are provided by the base Solr container
+# image. solr-recreate replaces the core config on the persistent volume with
+# the config-set from this image on every start, so config-set changes reach
+# existing cores. exec makes Solr the direct child of tini to receive SIGTERM.
+CMD ["sh", "-c", "solr-recreate drupal /solr-conf && exec solr-foreground"]
diff --git a/.vortex/tests/phpunit/Functional/DockerComposeSolrTest.php b/.vortex/tests/phpunit/Functional/DockerComposeSolrTest.php
new file mode 100644
index 0000000000..4d16009076
--- /dev/null
+++ b/.vortex/tests/phpunit/Functional/DockerComposeSolrTest.php
@@ -0,0 +1,144 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DrevOps\Vortex\Tests\Functional;
+
+use AlexSkrypnyk\File\File;
+use PHPUnit\Framework\Attributes\Group;
+
+/**
+ * Tests the Solr core lifecycle on a persistent volume.
+ */
+class DockerComposeSolrTest extends FunctionalTestCase {
+
+  const SOLR_URL = 'http://localhost:8983/solr';
+
+  const SOLR_DOC_ID = 'vortex-test-doc';
+
+  protected function setUp(): void {
+    parent::setUp();
+
+    static::$sutInstallerEnv = [];
+    static::$sutInstallerPrompts = [];
+
+    $this->forceVolumesUnmounted();
+
+    $this->dockerCleanup();
+  }
+
+  #[Group('p5')]
+  public function testSolrCoreConfigUpdate(): void {
+    $this->prepareSut();
+    $this->solrStart();
+
+    $this->logSubstep('Asserting the initial core config');
+    $this->assertSame('2000', $this->solrMltTimeAllowed(), 'Core should load the config-set shipped in the image');
+
+    $this->solrIndexDocument();
+
+    $this->logSubstep('Changing the config-set and rolling out a new image on the same volume');
+    File::replaceContentInFile('.docker/config/solr/config-set/solrcore.properties', 'solr.mlt.timeAllowed=2000', 'solr.mlt.timeAllowed=2345');
+    $this->assertFileContainsString('.docker/config/solr/config-set/solrcore.properties', 'solr.mlt.timeAllowed=2345');
+    $this->solrStart(recreate: TRUE);
+
+    $this->logSubstep('Asserting the existing core uses the changed config-set');
+    $this->assertSame('2345', $this->solrMltTimeAllowed(), 'Existing core should load the changed config-set');
+    $this->assertSame(1, $this->solrDocumentCount(), 'Index should survive the core config refresh');
+
+    $this->logSubstep('Asserting Solr is a direct child of the init process');
+    $process = $this->cmd('docker compose exec -T solr ps -o ppid= -C java', txt: 'Find the parent of the Java process');
+    $this->assertSame('1', trim($process->getOutput()), 'Java should be a direct child of tini to receive SIGTERM');
+  }
+
+  #[Group('p5')]
+  public function testSolrCoreIncompatibleConfigReplaced(): void {
+    $this->prepareSut();
+    $this->solrStart();
+    $this->solrIndexDocument();
+
+    $this->logSubstep('Writing a Solr 8 response writer into the core config on the volume');
+    $this->cmd('docker compose exec -T solr sed -i', txt: 'Inject Solr 8 config into the core on the volume', arg: ['s#</config>#<queryResponseWriter name="xslt" class="solr.XSLTResponseWriter"/></config>#', '/var/solr/data/drupal/conf/solrconfig.xml']);
+    $this->cmd('docker compose exec -T solr grep -q solr.XSLTResponseWriter /var/solr/data/drupal/conf/solrconfig.xml', txt: 'Core config on the volume should contain the Solr 8 response writer');
+
+    $this->logSubstep('Rolling out the same image on the same volume');
+    $this->solrStart(recreate: TRUE);
+
+    $this->logSubstep('Asserting the core loads with the config-set from the image');
+    $this->assertSame(1, $this->solrDocumentCount(), 'Index should survive the core config refresh');
+  }
+
+  #[Group('p5')]
+  public function testSolrBuildFailsWhenDataDirUnmatched(): void {
+    $this->prepareSut();
+
+    $this->logSubstep('Changing the dataDir in the config-set so the build no longer matches it');
+    File::replaceContentInFile('.docker/config/solr/config-set/solrconfig.xml', '<dataDir>${solr.data.dir:}</dataDir>', '<dataDir>${solr.data.dir:/var/solr/data}</dataDir>');
+    $this->assertFileContainsString('.docker/config/solr/config-set/solrconfig.xml', '<dataDir>${solr.data.dir:/var/solr/data}</dataDir>');
+
+    $this->cmdFail('docker compose build solr', txt: 'Build should fail when the index location cannot be moved out of the core directory', tio: 600);
+  }
+
+  /**
+   * Start the Solr service and wait for the 'drupal' core to load.
+   *
+   * @param bool $recreate
+   *   Replace the running container, keeping the volume.
+   */
+  protected function solrStart(bool $recreate = FALSE): void {
+    $this->logSubstep($recreate ? 'Recreating the Solr container' : 'Starting the Solr container');
+    // The image tag is shared across SUTs, so build to avoid a stale image.
+    $this->cmd('docker compose up -d --build solr' . ($recreate ? ' --force-recreate' : ''), txt: 'Start Solr container', tio: 600);
+
+    $failures = [];
+    $core = [];
+    for ($i = 0; $i < 60; $i++) {
+      $process = $this->processRun('docker compose exec -T solr curl -sf', [static::SOLR_URL . '/admin/cores?action=STATUS&core=drupal&wt=json']);
+      $decoded = json_decode($process->getOutput(), TRUE);
+
+      if ($process->isSuccessful() && is_array($decoded)) {
+        $failures = is_array($decoded['initFailures'] ?? NULL) ? $decoded['initFailures'] : [];
+        $statuses = is_array($decoded['status'] ?? NULL) ? $decoded['status'] : [];
+        $core = is_array($statuses['drupal'] ?? NULL) ? $statuses['drupal'] : [];
+
+        // A core that is still loading is listed without its 'index' details.
+        if (isset($failures['drupal']) || isset($core['index'])) {
+          break;
+        }
+      }
+
+      sleep(2);
+    }
+
+    $this->assertArrayNotHasKey('drupal', $failures, 'Core should not fail to load: ' . json_encode($failures));
+    $this->assertArrayHasKey('index', $core, 'Solr should finish loading the core');
+    $this->assertSame('drupal', $core['name'] ?? NULL, 'Core should be loaded');
+  }
+
+  protected function solrIndexDocument(): void {
+    $this->logSubstep('Indexing a document');
+    $this->cmd('docker compose exec -T solr curl -sf -H Content-Type:application/json --data-binary', txt: 'Index a document', arg: ['[{"id":"' . static::SOLR_DOC_ID . '"}]', static::SOLR_URL . '/drupal/update?commit=true']);
+    $this->assertSame(1, $this->solrDocumentCount(), 'Indexed document should be searchable');
+  }
+
+  protected function solrDocumentCount(): int {
+    $response = $this->solrGetJson('/drupal/select?q=id:' . static::SOLR_DOC_ID . '&rows=0&wt=json');
+
+    return (int) ($response['response']['numFound'] ?? -1);
+  }
+
+  protected function solrMltTimeAllowed(): ?string {
+    $response = $this->solrGetJson('/drupal/config/requestHandler?componentName=/mlt&wt=json');
+
+    return $response['config']['requestHandler']['/mlt']['defaults']['timeAllowed'] ?? NULL;
+  }
+
+  protected function solrGetJson(string $path): array {
+    $process = $this->cmd('docker compose exec -T solr curl -sf', arg: [static::SOLR_URL . $path]);
+    $decoded = json_decode($process->getOutput(), TRUE);
+    $this->assertIsArray($decoded, 'Solr should return JSON for ' . $path);
+
+    return $decoded;
+  }
+
+}