on mac os docker service stuck on “preparing” state in swarm cluster

ocker@myvm1:~$ docker version
Client:
Version: 17.06.0-ce
API version: 1.30
Go version: go1.8.3
Git commit: 02c1d87
Built: Fri Jun 23 21:15:15 2017
OS/Arch: linux/amd64

Server:
Version: 17.06.0-ce
API version: 1.30 (minimum version 1.12)
Go version: go1.8.3
Git commit: 02c1d87
Built: Fri Jun 23 21:51:55 2017
OS/Arch: linux/amd64
Experimental: false

docker@myvm1:~$ docker stack services getstartedlab
ID NAME MODE REPLICAS IMAGE PORTS
27dlqighq0gf getstartedlab_web replicated 0/2 danielyuan2017/awesomeimages:part1 *:8090->80/tcp

ocker@myvm1:~$ docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
hc5xgmmaqdma2k7d3xetuv6wu myvm2 Ready Active
jhflr5686vfcx5wo3gx3zmhlh * myvm1 Ready Active Leader

docker stack ps getstartedlab
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
mpunjv611812 getstartedlab_web.2 danielyuan2017/awesomeimages:part1 myvm2 Running Preparing about an hour ago
lvqqpzqlndsh getstartedlab_web.5 danielyuan2017/awesomeimages:part1 myvm1 Running Preparing 38 minutes ago

docker stack file:

version: "3"
services:
web:
image: danielyuan2017/awesomeimages:part1
deploy:
replicas: 2
resources:
limits:
cpus: "0.1"
memory: 50M
restart_policy:
condition: on-failure
ports:
- "8090:80"
networks:
- webnet
networks:
webnet:

Start with the reported docker stack services, docker node ls, and docker stack ps output, focusing on tasks remaining in Preparing on both nodes. Reproduce the deployment with the supplied stack file and image, then use the task state and daemon information to identify the cause and verify that the services reach the expected replica state.