title: The container from the worker node can't join the swarm's attachable network
body: <p>I encounter a problem when using the 'docker run' on the worker node,
  the scenario is as follows:</p>
  
  <p>I have following three VMs in my environment,
  and they are already in the Swarn mode.</p>
  
  <pre><code>VM.1 -&gt; Master node in the Swarm
  VM.2 -&gt; Worker node in the Swarm
  VM.3 -&gt; Worker node in the Swarm
  </code></pre>
  
  <p>and I've also created the overlay network in this environment via:</p>
  
  <pre><code>docker network create --attachable --driver overlay --subnet 10.10.0.0/16 --gateway 10.10.0.1 test-net
  </code></pre>
  
  <p>and the overlay network is created successfully</p>
  
  <pre><code># docker network ls
  NETWORK ID          NAME                DRIVER              SCOPE
  fc1b70304011        bridge              bridge              local
  f9ca924c1a4d        docker_gwbridge     bridge              local
  ea8fc696d6f1        host                host                local
  r311gaq7iobo        ingress             overlay             swarm
  bd08afac574d        none                null                local
  wb7vfpxzdkyt        test-net            overlay             swarm
  </code></pre>
  
  <p>but, once I use 'docker run' to run a container and let it join the "test-net" from the worker node(VM.2 and VM.3), then I will encounter the following problem:</p>
  
  <pre><code>    # docker run -itd --name=test --net=test-net kafka:latest
      c0324e6c3a8720b291cfc3aa7980846348f7a4450381036927924c52d343f622
      docker: Error response from daemon: error creating external 
      connectivity network: 
      cannot create network 
      246bb018a15a6641a9cb26afec30c62eb4714816cfc0a307786c8a209a2418e6 
      (docker_gwbridge): 
       conflicts with network 
       0093ca50dcbcf729aeeae537f424727b674843312ef63ea647db48c7b0077e45 
       (docker_gwbridge): networks have same bridge name.
  </code></pre>
  
  <p>but, it will be worked if I use the same 'docker run' command on the Master node, I've google this problem for serval times but still not understand what is happening on the worker node...</p>
  
  <p>Thanks for your reading and help! </p>