Log host name (#11776)

Summary:
... in info_log. Becoming more important with disaggregated storage.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11776

Test Plan: manual

Reviewed By: jaykorean

Differential Revision: D48849471

Pulled By: pdillinger

fbshipit-source-id: 9a8fd8b2564a4f133526ecd7c1414cb667e4ba54

db/db_info_dumper.cc

@@ -34,6 +34,12 @@ void DumpDBFileSummary(const ImmutableDBOptions& options,
   std::string file_info, wal_info;
 
   Header(options.info_log, "DB SUMMARY\n");
+  {
+    std::string hostname;
+    if (env->GetHostNameString(&hostname).ok()) {
+      Header(options.info_log, "Host name (Env):  %s\n", hostname.c_str());
+    }
+  }
   Header(options.info_log, "DB Session ID:  %s\n", session_id.c_str());
 
   Status s;