diff --git a/src/main/resources/Documentation/about.md b/src/main/resources/Documentation/about.md
index c7196c6..1d1a02b 100644
--- a/src/main/resources/Documentation/about.md
+++ b/src/main/resources/Documentation/about.md
@@ -57,9 +57,10 @@
 
 For the masters:
 
-* Configure database section in gerrit.config to use the shared database
+* Configure the database section in gerrit.config to use the shared database
 * Configure gerrit.basePath in gerrit.config to the shared repositories location
-* Install and configure @PLUGIN@ plugin
+* Configure gerrit.serverId in gerrit.config based on [config](config.md)'s introduction
+* Install and configure this @PLUGIN@ plugin [further](config.md) or based on below.
 
 Here is an example of the minimal @PLUGIN@.config:
 
diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index e79cbdd..377626d 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md
@@ -2,8 +2,14 @@
 @PLUGIN@ Configuration
 =========================
 
-The @PLUGIN@ plugin must be installed on all the instances and the following fields
-should be specified in `$site_path/etc/@PLUGIN@.config` file:
+The @PLUGIN@ plugin must be installed on all the instances. Each instance should
+be configured with the same [gerrit.serverId](https://gerrit-documentation.storage.googleapis.com/Documentation/3.2.0/config-gerrit.html#gerrit.serverId).
+If there are existing changes in [NoteDb](https://gerrit-documentation.storage.googleapis.com/Documentation/3.2.0/note-db.html)
+made with another `serverId`, then this plugin might not be able to access them.
+Likewise, if the HA gerrit.serverIds differ, then changes conveyed by one
+instance will not be accessible by the other.
+
+The following fields should be specified in `$site_path/etc/@PLUGIN@.config` files:
 
 File '@PLUGIN@.config'
 --------------------
diff --git a/src/test/docker/etc/gerrit.config b/src/test/docker/etc/gerrit.config
index a4728b6..90a4057 100644
--- a/src/test/docker/etc/gerrit.config
+++ b/src/test/docker/etc/gerrit.config
@@ -1,6 +1,7 @@
 [gerrit]
 	basePath = git
 	canonicalWebUrl = http://gerrit:8080/
+	serverId = f7696647-8efd-41b1-bd60-d321bc071ea9
 [index]
 	type = LUCENE
 [auth]