lxc-create fails on IPv6 address

[Tim Spriggs]

root@cps3:~/lxc# cat horizon-cps3.net.conf
lxc.network.type = veth
lxc.network.flags = up
lxc.network.link = br18
lxc.network.name = eth0
lxc.network.hwaddr = 00:16:3e:00:02:70
lxc.network.ipv6 = 2607:f088:0:12::39
lxc.network.mtu = 9000

root@cps3:~/lxc# lxc-create -n horizon-cps3 -f horizon-cps3.net.conf -t ubuntu -B none
lxc-create: Failed to create backing store type none

lxc-create: Error creating backing store type none for horizon-cps3
lxc-create: Error creating container horizon-cps3

root@cps3:~/lxc# lxc-create -n horizon-cps3 -f horizon-cps3.net.conf -t ubuntu
lxc-create: No such file or directory - invalid ipv6 address: 38.7.240.136
lxc-create: Error creating container horizon-cps3

The same template (different IP/mac) worked on raring.

root@cps3:~/lxc# dpkg -l lxc | awk '/lxc/ {print $3}'
1.0.0~alpha1-0ubuntu14

[Stéphane Graber (stgraber)]

Can you start your container with "-l debug -o debug" and attach the debug file generated?

[Tim Spriggs (tims-t)]

Sure thing, by "start" I assume you mean "create" since there is nothing created yet. There are only three lines in the debug output, I'll just paste it here:

root@cps3:~/lxc# lxc-create -n horizon-cps3 -f horizon-cps3.net.conf -t ubuntu -l debug -o debug
lxc-create: No such file or directory - invalid ipv6 address: 38.7.240.136
lxc-create: Error creating container horizon-cps3

root@cps3:~/lxc# cat debug
     lxc-create 1386289012.783 WARN lxc_log - lxc_log_init called with log already initialized
     lxc-create 1386289012.784 ERROR lxc_confile - No such file or directory - invalid ipv6 address: 38.7.240.136
     lxc-create 1386289012.785 ERROR lxc_create - Error creating container horizon-cps3

[Tim Spriggs (tims-t)]

Not sure if this is clear to everyone else so as a hint (I haven't looked at the code for lxc) the "IPv6" address shown gives a pretty good indication that something is parsing an IPv6 address and then representing the first 32 bits as an IPv4 address.

The specified ip address is 2607:f088:...
which we then split up into bytes: 26 07 f0 88
and then represent as base 10:

root@cps3:~/lxc# printf "%d.%d.%d.%d\n" 0x26 0x07 0xf0 0x88
38.7.240.136

anything that looks like address=ip is probably suspect.

[Stéphane Graber (stgraber)]

Yeah, I figured as much but looking at the code there's nothing obviously wrong...

I even managed to get LXC to say:
lxc_container: Failed to parse config: lxc.network.ipv6 = 38.7.240.136

Which is supposed to be a verbatim copy of the line it just read from the file... so I'm not sure what's somehow altering that value but it's perplexing... I'm doing some test builds with added debugging now to try and track down what's going on.

[Stéphane Graber (stgraber)]

Fix pushed upstream (rather obvious once I started looking at the right place...).
https://github.com/lxc/lxc/commit/64994c030ccf3980a34bc93072155b2810b8f691