[lxc-devel] [lxc/lxc] e54864: Clone bridge interface MTU setting

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/lxc/lxc
  Commit: e54864d3632e3959bed6dd6b7e6d2cbd7eb8eec0
      https://github.com/lxc/lxc/commit/e54864d3632e3959bed6dd6b7e6d2cbd7eb8eec0
  Author: Natanael Copa <ncopa at alpinelinux.org>
  Date:   2015-08-27 (Thu, 27 Aug 2015)

  Changed paths:
    M src/lxc/conf.c

  Log Message:
  -----------
  Clone bridge interface MTU setting

Instead of require static mtu setting in config we simply clone the
existing MTU setting of the bridge interface.

This fixes issue when bridge interface has bigger MTU (like 9000 for
jumbo frame support) than the default 1500. When veth interface is
created it has by default MTU set to 1500 and when this is added to the
bridge, the kernel wee reduce the MTU for the bridge to 1500. We solve
this by cloning the MTU value from bridge interface.

This simplifies managing containers with bridge interface who supports
jumbo frames (mtu 9000) and makes it easier to move containers between
hosts with different MTU settings.

Signed-off-by: Natanael Copa <ncopa at alpinelinux.org>
Acked-by: Stéphane Graber <stgraber at ubuntu.com>