title: Kubernetes pods can't connect between machines
body: <p>I used the node.yaml and master.yaml files here: <a href="http://kubernetes.io/v1.1/docs/getting-started-guides/coreos/coreos_multinode_cluster.html" rel="nofollow">http://kubernetes.io/v1.1/docs/getting-started-guides/coreos/coreos_multinode_cluster.html</a> to create a multi-node cluster on 3 bare-metal machines running CoreOS. However, pods on different nodes can’t communicate with each other. I’d appreciate any pointers or suggestions. I’m at a loss.</p>
  
  <p>I have three pods running rabbitmq:</p>
  
  <pre><code>thuey:~ thuey$ kbg pods | grep rabbitmq
  rabbitmq-bootstrap     1/1       Running   0          3h
  rabbitmq-jz2q7         1/1       Running   0          3h
  rabbitmq-mrnfc         1/1       Running   0          3h
  </code></pre>
  
  <p>Two of the pods are on one machine:</p>
  
  <pre><code>kbd node jolt-server-3 | grep rabbitmq
  thuey               rabbitmq-bootstrap      0 (0%)      0 (0%)      0 (0%)      0 (0%)
  thuey               rabbitmq-jz2q7          0 (0%)      0 (0%)      0 (0%)      0 (0%)
  </code></pre>
  
  <p>And the other pod is on another machine:</p>
  
  <pre><code>thuey:~ thuey$ kbd node jolt-server-4 | grep rabbitmq
  thuey               rabbitmq-mrnfc          0 (0%)      0 (0%)      0 (0%)      0 (0%)
  </code></pre>
  
  <p>I can successfully ping from rabbitmq-bootstrap to rabbitmq-jz2q7:</p>
  
  <pre><code>root@rabbitmq-bootstrap:/# ping 172.17.0.5
  PING 172.17.0.5 (172.17.0.5) 56(84) bytes of data.
  64 bytes from 172.17.0.5: icmp_seq=1 ttl=64 time=0.058 ms
  64 bytes from 172.17.0.5: icmp_seq=2 ttl=64 time=0.035 ms
  64 bytes from 172.17.0.5: icmp_seq=3 ttl=64 time=0.064 ms
  64 bytes from 172.17.0.5: icmp_seq=4 ttl=64 time=0.055 ms
  ^C
  --- 172.17.0.5 ping statistics ---
  4 packets transmitted, 4 received, 0% packet loss, time 3000ms
  rtt min/avg/max/mdev = 0.035/0.053/0.064/0.010 ms
  </code></pre>
  
  <p>But I can't ping rabbitmq-mrnfc:</p>
  
  <pre><code>root@rabbitmq-bootstrap:/# ping 172.17.0.8
  PING 172.17.0.8 (172.17.0.8) 56(84) bytes of data.
  From 172.17.0.2 icmp_seq=1 Destination Host Unreachable
  From 172.17.0.2 icmp_seq=2 Destination Host Unreachable
  From 172.17.0.2 icmp_seq=3 Destination Host Unreachable
  From 172.17.0.2 icmp_seq=4 Destination Host Unreachable
  ^C
  --- 172.17.0.8 ping statistics ---
  5 packets transmitted, 0 received, +4 errors, 100% packet loss, time 4000ms
  pipe 4
  </code></pre>