feat(scrubber): post scan_metadata results to storage controller (#8502)

Part of #8128, followup to #8480. closes #8421. 

Enable scrubber to optionally post metadata scan health results to
storage controller.

Signed-off-by: Yuchen Liang <yuchen@neon.tech>

test_runner/fixtures/neon_fixtures.py

@@ -4401,10 +4401,11 @@ class StorageScrubber:
         assert stdout is not None
         return stdout
 
-    def scan_metadata(self) -> Any:
-        stdout = self.scrubber_cli(
-            ["scan-metadata", "--node-kind", "pageserver", "--json"], timeout=30
-        )
+    def scan_metadata(self, post_to_storage_controller: bool = False) -> Any:
+        args = ["scan-metadata", "--node-kind", "pageserver", "--json"]
+        if post_to_storage_controller:
+            args.append("--post")
+        stdout = self.scrubber_cli(args, timeout=30)
 
         try:
             return json.loads(stdout)

test_runner/regress/test_storage_scrubber.py

@@ -440,10 +440,12 @@ def test_scrubber_scan_pageserver_metadata(
     assert len(index.layer_metadata) > 0
     it = iter(index.layer_metadata.items())
 
-    scan_summary = env.storage_scrubber.scan_metadata()
+    scan_summary = env.storage_scrubber.scan_metadata(post_to_storage_controller=True)
     assert not scan_summary["with_warnings"]
     assert not scan_summary["with_errors"]
 
+    assert env.storage_controller.metadata_health_is_healthy()
+
     # Delete a layer file that is listed in the index.
     layer, metadata = next(it)
     log.info(f"Deleting {timeline_path}/{layer.to_str()}")
@@ -453,7 +455,17 @@ def test_scrubber_scan_pageserver_metadata(
     )
     log.info(f"delete response: {delete_response}")
 
-    # Check scan summary. Expect it to be a L0 layer so only emit warnings.
+    # Check scan summary without posting to storage controller. Expect it to be a L0 layer so only emit warnings.
     scan_summary = env.storage_scrubber.scan_metadata()
     log.info(f"{pprint.pformat(scan_summary)}")
     assert len(scan_summary["with_warnings"]) > 0
+
+    assert env.storage_controller.metadata_health_is_healthy()
+
+    # Now post to storage controller, expect seeing one unhealthy health record
+    scan_summary = env.storage_scrubber.scan_metadata(post_to_storage_controller=True)
+    log.info(f"{pprint.pformat(scan_summary)}")
+    assert len(scan_summary["with_warnings"]) > 0
+
+    unhealthy = env.storage_controller.metadata_health_list_unhealthy()["unhealthy_tenant_shards"]
+    assert len(unhealthy) == 1 and unhealthy[0] == str(tenant_shard_id)