nova docker config file /etc/default/docker can't work for contianer mtu

[linwei,wu]

1.check /etc/default/docker file
DOCKER_OPTS='--graph=/openstack/docker --storage-driver=devicemapper --dns=8.8.8.8 --iptables=false'

2.add mtu to 1400 in this file
DOCKER_OPTS='--graph=/openstack/docker --storage-driver=devicemapper --dns=8.8.8.8 --iptables=false --mtu=1400'

3. service docker restart

4.boot an instance on this host
root@dev-mon-host-03:~# nova boot --flavor 100 --image leo_ubuntu --availability-zone docker:dev-mon-host-03 --nic net-id=1b047142-19a1-4e89-9de9-e21c3b47b29b linwwu_test

5.login docker container and check instance inteface mtu. it's still 1500
root@instance-000019ce:/# ifconfig
lo Link encap:Local Loopback
          inet addr:127.0.0.1 Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING MTU:65536 Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

nsd66d4d61-09 Link encap:Ethernet HWaddr fa:16:3e:7c:51:a8
          inet addr:100.64.14.223 Bcast:0.0.0.0 Mask:255.255.255.0
          inet6 addr: fe80::f816:3eff:fe7c:51a8/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
          RX packets:69 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:4192 (4.1 KB) TX bytes:648 (648.0 B)

6. if we create a docker instance directly, we will see that container interface can be changed.

so this is a bug in nova docker.

[Date Huang (tjjh89017)]

Docker daemon's option "mtu" work on docker bridge rather than which nova-docker uses.
You need to patch vifs.py some part to get the result you want.