From 9bcef7ffdaf1abdec025ada7802976fc4b58b6a5 Mon Sep 17 00:00:00 2001
From: Allison Easton <allison.easton@mongodb.com>
Date: Thu, 2 Apr 2026 16:44:59 +0200
Subject: [PATCH] SERVER-104223 Failures in preWarmConnectionPool() will cause
 mongos to fail startup (#35363) (#51032)

GitOrigin-RevId: 9a09afa25ef7b5846afcd1f9224ab8921b5acc8b
---
 src/mongo/s/mongos_main.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/mongo/s/mongos_main.cpp b/src/mongo/s/mongos_main.cpp
index ff21c300eb7..8329561afff 100644
--- a/src/mongo/s/mongos_main.cpp
+++ b/src/mongo/s/mongos_main.cpp
@@ -716,6 +716,8 @@ Status initializeSharding(
         LOGV2_WARNING(6203601, "Failed to warmup routing information", "error"_attr = redact(ex));
     }
 
+    // Pre-warm the connection pool may fail. Since this is just an optimization, any failure must
+    // not prevent mongos from starting.
     {
         auto scopedTimer =
             createTimeElapsedBuilderScopedTimer(opCtx->getServiceContext()->getFastClockSource(),
@@ -723,7 +725,8 @@ Status initializeSharding(
                                                 startupTimeElapsedBuilder);
         Status status = preWarmConnectionPool(opCtx);
         if (!status.isOK()) {
-            return status;
+            LOGV2_WARNING(
+                104223, "Failed to warmup the collection pool", "error"_attr = status.reason());
         }
     }