diff --git a/manual/docker/cluster/seafile-server.yml b/manual/docker/cluster/seafile-server.yml
index a8111979..14fa45d2 100644
--- a/manual/docker/cluster/seafile-server.yml
+++ b/manual/docker/cluster/seafile-server.yml
@@ -32,6 +32,7 @@ services:
       - INIT_S3_HOST=${INIT_S3_HOST:-us-east-1:-}
       - INIT_S3_USE_HTTPS=${INIT_S3_USE_HTTPS:-true}
       - JWT_PRIVATE_KEY=${JWT_PRIVATE_KEY:?Variable is not set or empty}
+      - SITE_ROOT=${SITE_ROOT:-/}
       - ENABLE_SEADOC=${ENABLE_SEADOC:-false}
       - SEADOC_SERVER_URL=${SEADOC_SERVER_URL:-http://example.example.com/sdoc-server}