App engine not spliting traffic to new version

[Rahul Goti]

I have deployed one service on App Engine Flex with manual scaling configuration. If I deploy a new version with below command then it expected to stop the previous version and split all traffic to the newer version. But It can't do that and all traffic still serving by existing version only.

gcloud app deploy src/main/appengine/app.yaml --image-url gcr.io/$PROJECT_ID/my-services-xxx:187 --promote --stop-previous-version --version=187

app.yaml file (to verify it is manual scaling service) : 

runtime: java
env: flex

service: my-service-xxx

runtime_config:  # Optional
  jdk: openjdk8

handlers:
- url: /.*
  script: this field is required, but ignored

manual_scaling:
  instances: 1

resources:
  cpu: 1
  memory_gb: 2
  disk_size_gb: 10

[Julie (cloud platform support)]

Thanks for reporting this. This is likely related to a reported issue tracker[1] regarding App Engine Flex where the cause is likely due to connection issues or some other change interrupts the run of gcloud which causes the previous versions will be left in their existing state. As a workaround, you can split traffic to the new version to migrate traffic as detailed by the below gcloud command[2] or though the Cloud Console (please note that the information in the document[2] is incorrect, you will need to use traffic splitting for App Engine Flex in the Console[3]). 

[1] https://issuetracker.google.com/63711899

[2] https://cloud.google.com/appengine/docs/flexible/java/migrating-traffic

[3] https://cloud.google.com/appengine/docs/flexible/python/splitting-traffic#splitting_traffic_across_multiple_versions