title: docker-compose network creation kicks me out of ssh
body: <p>I need help understanding my networking logs due to <code>docker-compose</code> networking.</p>
  <p>I'm ssh'd into a <strong>VM</strong>, and I have two projects with docker-compose. The first is launched simply with <code>docker-compose up</code>. When I try to launch the second, my ssh session freezes, and I can no longer ssh into the VM. After lots of trial and error, and after reading <a href="https://docs.docker.com/compose/networking/#/using-a-pre-existing-network" rel="nofollow noreferrer">this</a> I tried to append to my 2nd project's <code>docker-compose.yml</code> file the following:</p>
  <pre><code>networks:
    default:
      external:
        name: abcdef_default
  </code></pre>
  <p>where <code>abcdef_default</code> is the name of the network created by <code>docker-compose up</code> of the 1st project. With this, the <code>docker-compose up</code> on the 2nd project doesn't kick me out of the ssh session.</p>
  <p>I tailed the logs in <code>/var/log/*.log</code>, and here's the output <em>with</em> the networks section in the <code>docker-compose.yml</code> file (without the timestamp prefix: <code>Jan 19 09:13:42 hostname kernel: [420096.305357]</code>):</p>
  <pre><code>aufs au_opts_verify:1597:dockerd[13813]: dirperm1 breaks the protection by the permission bits on the lower branch
  device veth6a84537 entered promiscuous mode
  IPv6: ADDRCONF(NETDEV_UP): veth6a84537: link is not ready
  eth0: renamed from veth2480623
  IPv6: ADDRCONF(NETDEV_CHANGE): veth6a84537: link becomes ready
  br-fe0deb0149df: port 18(veth6a84537) entered forwarding state
  br-fe0deb0149df: port 18(veth6a84537) entered forwarding state
  aufs au_opts_verify:1597:dockerd[25317]: dirperm1 breaks the protection by the permission bits on the lower branch
  device veth1a3c1e3 entered promiscuous mode
  IPv6: ADDRCONF(NETDEV_UP): veth1a3c1e3: link is not ready
  br-fe0deb0149df: port 22(veth1a3c1e3) entered forwarding state
  br-fe0deb0149df: port 22(veth1a3c1e3) entered forwarding state
  eth0: renamed from veth54e576d
  IPv6: ADDRCONF(NETDEV_CHANGE): veth1a3c1e3: link becomes ready
  br-fe0deb0149df: port 22(veth1a3c1e3) entered disabled state
  veth54e576d: renamed from eth0
  br-fe0deb0149df: port 22(veth1a3c1e3) entered disabled state
  device veth1a3c1e3 left promiscuous mode
  br-fe0deb0149df: port 22(veth1a3c1e3) entered disabled state
  br-fe0deb0149df: port 18(veth6a84537) entered forwarding state
  </code></pre>
  <p>and here's the output <em>without</em> the <code>networks</code> section (i.e. when I get kicked out of the ssh session):</p>
  <pre><code>IPv6: ADDRCONF(NETDEV_UP): br-55349b03453a: link is not ready
  aufs au_opts_verify:1597:dockerd[26982]: dirperm1 breaks the protection by the permission bits on the lower branch
  aufs au_opts_verify:1597:dockerd[26982]: dirperm1 breaks the protection by the permission bits on the lower branch
  aufs au_opts_verify:1597:dockerd[3051]: dirperm1 breaks the protection by the permission bits on the lower branch
  device veth7a1bcde entered promiscuous mode
  IPv6: ADDRCONF(NETDEV_UP): veth7a1bcde: link is not ready
  br-55349b03453a: port 1(veth7a1bcde) entered forwarding state
  br-55349b03453a: port 1(veth7a1bcde) entered forwarding state
  br-55349b03453a: port 1(veth7a1bcde) entered disabled state
  eth0: renamed from veth5d8a2ea
  IPv6: ADDRCONF(NETDEV_CHANGE): veth7a1bcde: link becomes ready
  br-55349b03453a: port 1(veth7a1bcde) entered forwarding state
  br-55349b03453a: port 1(veth7a1bcde) entered forwarding state
  IPv6: ADDRCONF(NETDEV_CHANGE): br-55349b03453a: link becomes ready
  aufs au_opts_verify:1597:dockerd[13814]: dirperm1 breaks the protection by the permission bits on the lower branch
  aufs au_opts_verify:1597:dockerd[13814]: dirperm1 breaks the protection by the permission bits on the lower branch
  aufs au_opts_verify:1597:dockerd[13922]: dirperm1 breaks the protection by the permission bits on the lower branch
  device veth3253bd4 entered promiscuous mode
  IPv6: ADDRCONF(NETDEV_UP): veth3253bd4: link is not ready
  br-55349b03453a: port 2(veth3253bd4) entered forwarding state
  br-55349b03453a: port 2(veth3253bd4) entered forwarding state
  br-55349b03453a: port 2(veth3253bd4) entered disabled state
  eth0: renamed from veth9c8aaa3
  IPv6: ADDRCONF(NETDEV_CHANGE): veth3253bd4: link becomes ready
  br-55349b03453a: port 2(veth3253bd4) entered forwarding state
  br-55349b03453a: port 2(veth3253bd4) entered forwarding state
  br-55349b03453a: port 2(veth3253bd4) entered disabled state
  veth9c8aaa3: renamed from eth0
  br-55349b03453a: port 2(veth3253bd4) entered disabled state
  device veth3253bd4 left promiscuous mode
  br-55349b03453a: port 2(veth3253bd4) entered disabled state
  br-55349b03453a: port 1(veth7a1bcde) entered forwarding state
  br-55349b03453a: port 1(veth7a1bcde) entered disabled state
  veth5d8a2ea: renamed from eth0
  br-55349b03453a: port 1(veth7a1bcde) entered disabled state
  device veth7a1bcde left promiscuous mode
  br-55349b03453a: port 1(veth7a1bcde) entered disabled state
  </code></pre>
  <p>I don't really understand how to read these logs.
  <a href="http://paste.ubuntu.com/23826643/" rel="nofollow noreferrer">Here</a> is my <code>ifconfig</code> also.
  Can someone help me read the logs and figure out what the problem is?</p>