From 57242f790ef88f6dd9a804d56e0089fd7ac8dbed Mon Sep 17 00:00:00 2001
From: Matthias Radestock <matthias.radestock@gmail.com>
Date: Fri, 28 Nov 2014 11:06:36 +0000
Subject: [PATCH] check that weave container has an eth0 since w/o that we get
 an obscure error.

The most likely cause for not having an eth0 is that the docker daemon
has been configured to disable container networking.
---
 weave | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/weave b/weave
index 7eb5164c..97cf936a 100755
--- a/weave
+++ b/weave
@@ -216,6 +216,10 @@ connect_container_to_bridge() {
 }
 
 launch() {
+    if ! ip netns exec $NETNS ip link show eth0 >/dev/null 2>&1 ; then
+        echo "No eth0 interface inside $CONTAINER_NAME container; perhaps you are running the docker daemon with container networking disabled (-b=none)." >&2
+        return 1
+    fi
     connect_container_to_bridge &&
         check_command_and_run_anything ethtool ip netns exec $NETNS ethtool -K eth0 tx off >/dev/null &&
         ip netns exec $NETNS ip link set $CONTAINER_IFNAME up