diff --git a/.github/workflows/spack_cpu_build.yaml b/.github/workflows/spack_cpu_build.yaml
index 287944fa..1be4ea40 100644
--- a/.github/workflows/spack_cpu_build.yaml
+++ b/.github/workflows/spack_cpu_build.yaml
@@ -8,7 +8,7 @@ jobs:
     # 20.04 is a version shared by E4S cache and Spack binaries for x86_64
     runs-on: ubuntu-20.04
     # This seems redundant if we use a spack submodule?
-    # container: spack/ubuntu-focal:latest
+    container: spack/ubuntu-focal:latest
     strategy:
       matrix:
         spack_spec: