Merge pull request #3835 from puerco/serial-build

Temporarily Run Builds Serially

Author: k8s-ci-robot

gcb/stage/cloudbuild.yaml

@@ -78,6 +78,7 @@ steps:
   - "K8S_REPO=${_K8S_REPO}"
   - "K8S_REF=${_K8S_REF}"
   - GOOGLE_SERVICE_ACCOUNT_NAME=krel-staging@k8s-releng-prod.iam.gserviceaccount.com
+  - "KUBE_PARALLEL_BUILD_MEMORY=64"
   secretEnv:
   - GITHUB_TOKEN
   - DOCKERHUB_TOKEN