diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index cfaad7ca..e6a69879 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -6,6 +6,14 @@ on:
   pull_request:
     branches: [ master ]
 
+# One deploy at a time. Two merges seconds apart raced here: both runs did
+# docker rm -f then docker run, the second removed the container the first had
+# just created, and the first's docker run then failed on a name conflict -
+# leaving the demo on the older image with a red deploy.
+concurrency:
+  group: deploy-${{ github.ref }}
+  cancel-in-progress: false
+
 env:
   IMAGE_NAME: registry.ap-northeast-1.aliyuncs.com/go-admin/go-admin-api # 镜像名称
   TAG: ${{ github.sha }}