Trusty update is missing IPv6 addresses (no ::1 on localhost)

[tiran]

The latest image is missing IPv6 addresses. The Kernel seems to have IPv6 enabled by no IPv6 addresses are configured. This breaks FreeIPA's test suite as we require IPv6 for some services. group: deprecated-2017Q4 fixes the problem.

In freeipa/freeipa#1391 and freeipa/freeipa#1392 we tried to set up IPv6. But the service does not have permission to modify the network stack. See https://travis-ci.org/freeipa/freeipa/jobs/315525816

$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1460 qdisc mq state UP group default qlen 1000
    link/ether 42:01:0a:14:00:6b brd ff:ff:ff:ff:ff:ff
    inet 10.20.0.107/32 brd 10.20.0.107 scope global eth0
       valid_lft forever preferred_lft forever
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:5d:b5:df:61 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 scope global docker0
       valid_lft forever preferred_lft forever

$ ip addr show lo | grep -q inet6 || sudo ip addr add ::1/128 dev lo
RTNETLINK answers: Permission denied


The command "ip addr show lo | grep -q inet6 || sudo ip addr add ::1/128 dev lo" failed and exited with 2 during .

[tiran]

The workaround group: deprecated-2017Q4 is no longer working for us. Even images from the deprecated group are lacking IPv6 support, e.g. https://travis-ci.org/freeipa/freeipa/jobs/315776280

[aidanhs]

Looking at that build config you're using sudo-disabled builds, apparently you need to enable sudo - https://blog.travis-ci.com/2017-12-12-new-trusty-images-q4-launch

[tiran]

I tried

sudo: required
dist: trusty
group: deprecated-2017Q4

but it doesn't make a difference. Loopback is still missing IPv6 address ::1. The Kernel has IPv6 support enabled, /proc/net/if_inet6 is present but empty.

[aidanhs]

Do you have a log for where you tried that (the one pasted doesn't have sudo enabled)? I'm just wondering because this did seem to fix it for the rust project.

[tiran]

@aidanhs thanks!

The job https://travis-ci.org/freeipa/freeipa/jobs/316348680 is running with sudo enabled and group: deprecated-2017Q4. As you can see in the before_install steps, IPv6 is enabled in the kernel (if_inet6 is present) but there is no IPv6 addressed assigned to any interface. You are running with language: shell, we are using language: python. I'll try that next.

[tiran]

@aidanhs With

language: shell
sudo: required
dist: trusty
group: deprecated-2017Q4

I'm still not getting ::1 or any other IPv6 address.

[zuercher]

@tiran for comparison, I added your before install commands to our build (https://travis-ci.org/envoyproxy/envoy/builds/316643185). The output matches -- seemingly showing no ipv6 network. However, our ipv6-based tests definitely pass with group: deprecated-2017Q4 set where they do not without it. We only use the loopback address for ipv6 testing, but perhaps that works inside the docker container, but not on the worker that launches the container?

@BanzaiMan all that aside, can we expect a fix for this anytime soon?

[GiedriusM]

You can try the following solution: #8361 (comment)

[BanzaiMan]

Sorry for the delay. We are removing localhost from ::1 aliases. See travis-ci/travis-build#1253 (and #8780).

[zuercher]

It's not a problem with localhost resolving to ::1. The problem is that ipv6 is disabled completely and we are running tests to explicitly test ipv6-related code.

[cotsog]

If you are running your tests in a Docker container, the following will enable back IPv6 support for Docker on Travis CI:

before_install:
  - echo '{"ipv6":true,"fixed-cidr-v6":"2001:db8:1::/64"}' | sudo tee /etc/docker/daemon.json
  - sudo service docker restart

Could you try this out and report back the result?

Thanks!

[kennytm]

Thanks @cotsog, this does work.