anchor.diff:  container on a Docker Swarm (v.1.12) cluster.
   
   First, set up a cluster, the Kubernetes libvirt coreos cluster
  -example works well, see link:http://kubernetes.io/docs/getting-started-guides/libvirt-coreos/[coreos-libvirt-cluster]
  +example works well, see link:http://kubernetes.io/docs/getting-started-guides/libvirt-coreos/[coreos-libvirt-cluster.]
   
   Next, on each node, create the Swarm using these
  -link:https://docs.docker.com/engine/swarm/swarm-tutorial/create-swarm/[Swarm Install]
  +link:https://docs.docker.com/engine/swarm/swarm-tutorial/create-swarm/[Swarm Install instructions.]
   
   Includes the command on the manager node:
   ....
  
positive.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
  
negative.code: 
  Look at the watch container logs to see it perform the failover.
  
  === Tips - Send a signal to postgres
  
  First, find the PID of the postmaster:
  
  ....
  docker exec -it master cat /pgdata/master/postmaster.pid
  ....
  
  Then, send it the signal to kill it or other signal depending on what you want to do:
  
  ....
  docker exec -it master kill -SIGTERM 22
  