diff --git a/.github/workflows/build_push.yml b/.github/workflows/build_push.yml
index 92b03a6f..399280a2 100644
--- a/.github/workflows/build_push.yml
+++ b/.github/workflows/build_push.yml
@@ -23,7 +23,7 @@ jobs:
     name: Prepare job
     runs-on: docker
     container: 
-      image: ubuntu-latest
+      env: CI_CHUNK_NUM: 10
     outputs:
       individualMatrix: ${{ steps.generate-matrices.outputs.individualMatrix }}
     steps: