title: configuring flannel to use a non default interface in kubernetes
body: <p>Is there a way to define in which interface Flannel should be listening? According to <a href="https://github.com/coreos/flannel/blob/master/Documentation/troubleshooting.md#vagrant" rel="noreferrer">his documentation</a> adding FLANNEL_OPTIONS="--iface=enp0s8" in /etc/sysconfig/flanneld should work, but it isn't. </p>
  
  <p>My master node configuration is running in a xenial(ubuntu 16.04) vagrant:</p>
  
  <pre><code>$ sudo kubeadm init --pod-network-cidr 10.244.0.0/16 --apiserver-advertise-address 10.0.0.10 
  
  $ kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
  clusterrole "flannel" created                                                                    
  clusterrolebinding "flannel" created                                                                   
  serviceaccount "flannel" created                                                                 
  configmap "kube-flannel-cfg" created                                                                                                                                                       
  daemonset "kube-flannel-ds" created   
  
  
  ubuntu@master:~$ kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/k8s-manifests/kube-flannel-rbac.yml
  clusterrole "flannel" configured                                                          
  clusterrolebinding "flannel" configured         
  </code></pre>
  
  <p>Host ip addresses:</p>
  
  <pre><code>$ ip addr                      
  1: lo: &lt;LOOPBACK,UP,LOWER_UP&gt; mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1     
      link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00                                    
      inet 127.0.0.1/8 scope host lo            
         valid_lft forever preferred_lft forever                                               
      inet6 ::1/128 scope host                  
         valid_lft forever preferred_lft forever                                               
  2: enp0s3: &lt;BROADCAST,MULTICAST,UP,LOWER_UP&gt; mtu 1500 qdisc pfifo_fast state UP group default qlen 1000                                                                                    
      link/ether 02:63:8e:2c:ef:cd brd ff:ff:ff:ff:ff:ff                                       
      inet 10.0.2.15/24 brd 10.0.2.255 scope global enp0s3                                     
         valid_lft forever preferred_lft forever                                               
      inet6 fe80::63:8eff:fe2c:efcd/64 scope link                                              
         valid_lft forever preferred_lft forever                                               
  3: enp0s8: &lt;BROADCAST,MULTICAST,UP,LOWER_UP&gt; mtu 1500 qdisc pfifo_fast state UP group default qlen 1000                                                                                    
      link/ether 08:00:27:fb:ad:bb brd ff:ff:ff:ff:ff:ff                                       
      inet 10.0.0.10/24 brd 10.0.0.255 scope global enp0s8                                     
         valid_lft forever preferred_lft forever                                               
  4: docker0: &lt;NO-CARRIER,BROADCAST,MULTICAST,UP&gt; mtu 1500 qdisc noqueue state DOWN group default                                                                                            
      link/ether 02:42:da:aa:6e:13 brd ff:ff:ff:ff:ff:ff                                       
      inet 172.17.0.1/16 scope global docker0   
         valid_lft forever preferred_lft forever                                               
  5: flannel.1: &lt;BROADCAST,MULTICAST,UP,LOWER_UP&gt; mtu 1450 qdisc noqueue state UNKNOWN group default                                                                                         
      link/ether 5e:07:a1:7f:97:53 brd ff:ff:ff:ff:ff:ff                                       
      inet 10.244.0.0/32 scope global flannel.1 
         valid_lft forever preferred_lft forever                                               
      inet6 fe80::5c07:a1ff:fe7f:9753/64 scope link                                            
         valid_lft forever preferred_lft forever                                               
  6: cni0: &lt;NO-CARRIER,BROADCAST,MULTICAST,UP&gt; mtu 1500 qdisc noqueue state DOWN group default qlen 1000                                                                                     
      link/ether 0a:58:0a:f4:00:01 brd ff:ff:ff:ff:ff:ff                                       
      inet 10.244.0.1/24 scope global cni0      
         valid_lft forever preferred_lft forever                                               
      inet6 fe80::7037:fcff:fe41:b1fb/64 scope link                                            
         valid_lft forever preferred_lft forever                  
  </code></pre>
  
  <p>Pods names:</p>
  
  <pre><code>$ kubectl get pods --all-namespaces                                                                                                                                         
  NAMESPACE     NAME                             READY     STATUS              RESTARTS   AGE  
  kube-system   etcd-master                      1/1       Running             0          2m   
  kube-system   kube-apiserver-master            1/1       Running             0          2m   
  kube-system   kube-controller-manager-master   1/1       Running             0          2m   
  kube-system   kube-dns-545bc4bfd4-gjjth        0/3       ContainerCreating   0          3m   
  kube-system   kube-flannel-ds-gdz8f            1/1       Running             0          1m   
  kube-system   kube-flannel-ds-h4fd2            1/1       Running             0          33s  
  kube-system   kube-flannel-ds-rnlsz            1/1       Running             1          33s  
  kube-system   kube-proxy-d4wv9                 1/1       Running             0          33s  
  kube-system   kube-proxy-fdkqn                 1/1       Running             0          3m   
  kube-system   kube-proxy-kj7tn                 1/1       Running             0          33s  
  kube-system   kube-scheduler-master            1/1       Running             0          2m   
  </code></pre>
  
  <p>Flannel Logs:</p>
  
  <pre><code>$ kubectl logs -n kube-system kube-flannel-ds-gdz8f -c kube-flannel
  I1216 12:00:35.817207       1 main.go:474] Determining IP address of default interface
  I1216 12:00:35.822082       1 main.go:487] Using interface with name enp0s3 and address 10.0.2.15
  I1216 12:00:35.822335       1 main.go:504] Defaulting external address to interface address (10.0.2.15)
  I1216 12:00:35.909906       1 kube.go:130] Waiting 10m0s for node controller to sync
  I1216 12:00:35.909950       1 kube.go:283] Starting kube subnet manager
  I1216 12:00:36.987719       1 kube.go:137] Node controller sync successful
  I1216 12:00:37.087300       1 main.go:234] Created subnet manager: Kubernetes Subnet Manager - master
  I1216 12:00:37.087433       1 main.go:237] Installing signal handlers
  I1216 12:00:37.088836       1 main.go:352] Found network config - Backend type: vxlan
  I1216 12:00:37.089018       1 vxlan.go:119] VXLAN config: VNI=1 Port=0 GBP=false DirectRouting=false
  I1216 12:00:37.295988       1 main.go:299] Wrote subnet file to /run/flannel/subnet.env
  I1216 12:00:37.296025       1 main.go:303] Running backend.
  I1216 12:00:37.296048       1 main.go:321] Waiting for all goroutines to exit
  I1216 12:00:37.296084       1 vxlan_network.go:56] watching for new subnet leases
  </code></pre>
  
  <p>How do I do to configure flannel in kubernetes <strong>to listen in enp0s8 instead of enp0s3</strong>?</p>