anchor.diff:  ....
   
   In the above example, the kubernetes-node-1 node with ID 18yrb7m650umx738rtevojpqy has a user defined label of *master* added to it.  The master service
  -specifies *master* as a constraint when created, this tells Swarm
  +specifies *master* as a constraint when created; this tells Swarm
   to place the service on that specific node.  The replica specifies
   a constraint of *node.labels.type != master* to have the replica
   always placed on a node that is not hosting the master service.
  
positive.code: ....
  
  We want to have the master database always placed on
  a specific node, we accomplish this using node constraints
  as follows:
  ....
  docker node inspect kubernetes-node-1 | grep ID
  
negative.code: container runs as the postgres user, so adjust the
  file permissions of /run/docker.sock accordingly.
  
  Run the example as follows (depends on master-replica example
  being run prior):
  ....
  cd examples/docker/watch
  