From 28fbb67d7782a5fbe76459e9b3b422b9ef0a30cb Mon Sep 17 00:00:00 2001
From: ian fogelman <ian.fogelman@mongodb.com>
Date: Thu, 28 Oct 2021 14:55:40 -0400
Subject: [PATCH]  DOCS-14644-assert CWWC is set on server start | DOCS-14643
 on sh.addShard

---
 .../fact-5.1-fassert-shard-restart-add-CWWC.rst      | 12 ++++++++++++
 source/reference/mongodb-defaults.txt                |  2 ++
 source/release-notes/5.1-compatibility.txt           |  5 +++++
 source/release-notes/5.1.txt                         |  5 +++++
 source/sharding.txt                                  |  2 ++
 5 files changed, 26 insertions(+)
 create mode 100644 source/includes/fact-5.1-fassert-shard-restart-add-CWWC.rst

diff --git a/source/includes/fact-5.1-fassert-shard-restart-add-CWWC.rst b/source/includes/fact-5.1-fassert-shard-restart-add-CWWC.rst
new file mode 100644
index 00000000000..ecc93fcf3dd
--- /dev/null
+++ b/source/includes/fact-5.1-fassert-shard-restart-add-CWWC.rst
@@ -0,0 +1,12 @@
+Starting in MongoDB 5.1, when starting, restarting or adding a
+:doc:`shard server</sharding>` with :method:`sh.addShard()` the
+:ref:`Cluster Wide Write Concern (CWWC) <set_global_default_write_concern>` 
+must be set.
+
+If the ``CWWC`` is not set and the shard is configured
+such that the :ref:`default write concern <write-concern>` is 
+``{ w : 1 }`` the shard server will fail to start or be added 
+and returns an error.
+
+See :ref:`default write concern calculations <default-wc-formula>` for 
+details on how the default write concern is calculated.
diff --git a/source/reference/mongodb-defaults.txt b/source/reference/mongodb-defaults.txt
index a0b7f91ac00..699a6501125 100644
--- a/source/reference/mongodb-defaults.txt
+++ b/source/reference/mongodb-defaults.txt
@@ -215,6 +215,8 @@ Write Concern
    :alt: Read/Write Concern Inheritance
    :figwidth: 500px
 
+.. _default-wc-formula:
+
 Default Write Concern
 ~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/source/release-notes/5.1-compatibility.txt b/source/release-notes/5.1-compatibility.txt
index c3ce44fdd2f..bc3f368c3b5 100644
--- a/source/release-notes/5.1-compatibility.txt
+++ b/source/release-notes/5.1-compatibility.txt
@@ -52,6 +52,11 @@ Shell Changes
 Replica Sets
 ------------
 
+Assert Cluster Wide Write Concern is Set When Starting or Adding Shard
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. include:: /includes/fact-5.1-fassert-shard-restart-add-CWWC.rst
+
 ``rs.reconfig`` Cluster Wide Write Concern Validation
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/source/release-notes/5.1.txt b/source/release-notes/5.1.txt
index b293432c72e..b9e18e1ed68 100644
--- a/source/release-notes/5.1.txt
+++ b/source/release-notes/5.1.txt
@@ -137,6 +137,11 @@ For an example, see :ref:`validation-description-example`.
 Replica Sets
 ------------
 
+Assert Cluster Wide Write Concern is Set When Starting or Adding Shard
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. include:: /includes/fact-5.1-fassert-shard-restart-add-CWWC.rst
+
 ``rs.reconfig`` Cluster Wide Write Concern Validation
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/source/sharding.txt b/source/sharding.txt
index 5d5afe70515..06f42c054fc 100644
--- a/source/sharding.txt
+++ b/source/sharding.txt
@@ -237,6 +237,8 @@ a :ref:`broadcast operation <sharding-mongos-broadcast>`, querying
 *all* shards in the sharded cluster. These scatter/gather queries can
 be long running operations.
 
+.. include:: /includes/fact-5.1-fassert-shard-restart-add-CWWC.rst
+
 .. note::
 
    If you have an active support contract with MongoDB, consider contacting