Public bug reported: Apparently lxdbr0 gets set up with the standard MTU of 1500 by default. However, in our data center interfaces have a lower one: Scalingstack instances have eth0 with MTU 1400, and on my local laptop the OpenVPN tun0 even has 1194 only.
This leads to the network in lxd containers being broken by default; while ping and mtr work, apt-get update is hanging forever. The main issue with this is that very few people are even aware of an MTU impedance mismatch, so debugging this always takes ages. It took me a while until I added this to my own autopkgtest stuff (https://git.launchpad.net/~ubuntu-release/+git/autopkgtest- cloud/tree/tools/armf-lxd-slave.userdata#n98): lxc profile device remove default eth0 lxc profile device add default eth0 nic nictype=bridged parent=lxdbr0 mtu=1400 and Michael just ran into it again with juju tests in bug 1571082. Can we be more clever here and configure a default MTU on lxdbr0 which matches the one from the host's default route? ** Affects: lxd (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1572026 Title: be more clever about MTU of lxdbr0 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lxd/+bug/1572026/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
