I want to add more worker nodes and scale up one of my stack services. I would expect my stack to keep working while scaling up workers.
When swarm-worker-vmss virtual machine scale starts resizing I loose connectivity to all the stack endpoints.
Steps to reproduce the behavior
1- Login into cloud.docker.com
2- Using Azure as a provider create a 1 Manager (VM DS4) and 4 Worker (VM DS3) swarm.
3- Once it is provisioned deploy a simple stack that exposes an HTTP endpoint.
4- Create a HTTP client that loops over calling one of the HTTP services. Leave it running forever.
5- Login into Portal Azure, navigate to the Swarm Resource Group, select the swarm-worker-vmss and scale to 10 workers.
6- The HTTP client in 4 dies with connections errors.
7- Retrying makes the client fail for a couple of minutes until the swarm services recover.
I have also reported this issue here: